the seller who rebuilt it, forgot to fully install the wrist pin retaining clip, the wrist pin worked its way out, got caught on the bottom of the cylinder bending the connecting rod and cracking the piston. that is why only half of the piston is cracked off
Sorry I didn't see your comment at the time I posted my comment I've seen this before most likely failure to install wrist pin clip or it could have had spiral clips and wasn't installed correctly
As a former longtime MC tech, I NEVER EVER trust an amateur’s work. It’s always a good idea to revisit any work a previous owner did to avoid issues like this.
Before I looked at the comments I had come to the exact same conclusion that the wrist pin clip had not been installed on the one side. I'll wager that you won't find any evidence of the second clip in the motor. Thanks for your content, I love it
After watching this entirely, I'm willing to bet that one of the wrist pin clips wasn't fully seated. Whoever rebuilt this engine forgot to listen for the snap.
You can see on the bottom right side of cylinder wall where the Piston pin scraped and caused piston to break. Like others have said it looks like the wrist pin clip wasn't installed all the way and fell off causing pin to slide out catching cylinder wall and or just caused piston pin journal to break.
Had bent rod situation about a year ago, could find parts, European junk. Heated rod a bit, used the press and got it back straight as an arrow. Ran fine after, still running today!! Crazy, was a hail Mary but it frkn worked. Setting up to straighten was the pain.
The crank is from Hot rods. I rebuild a yz250f and the rod had the same id system. If you search for hot rods connecting rod 616 you’ll find visibly identical cranks for the crf250r.
It's nice to read these comments, which seem to be 100% accurate on the reason the engine failed. It's unfortunate when a newly rebuilt engine fails in such a short amount of time. But, knowing why it happened is priceless knowledge. Love and appreciate your content.
Here's why I always double-check customer work. Admittedly, finding a misplaced wrist pin clip would've been impossible to see without a complete teardown, which I likely wouldn't have done, so I would've had the same result as Joe. I always hated dealing with other people's lack of mechanical knowledge.
@@craigdalzell2908 Not at all. If I were him I wouldn't bother with this engine and I'd just buy a replacement one instead. I'm sure it would be much cheaper and he wouldn't have to spend who knows how many hours tearing it down completely. He'd have to so he could get all of those loose metal fragments out of the engine entirely. I would never take the chance of just fishing out what I could see and cross my fingers for the rest.
If I had to guess the E clip came off and let the pin slide over to the wall and break one ear. Or maybe there was only one E clip. I am 67 years old and have been working on motorcycles for 55 years.And I still learn stuff from you all the time. Keep up the good work. And I wish when I was young I would have had the job you do.👍
I've seen this before. They either forgot one or both of the wrist pin 35:45 clips. Or did not get the clip properly into the groove. When the wrist pin slides over it puts all the stress on one eyelet of the bottom of the piston and that's why it broke.
wrist pin clip wasnt snapped in !!! YOU GOT LUCKY !!! engine immediately stopped instead of metal chunks taking out the cases and everything else!! 😃👍👍👍👍👍👍👍👍
People saying the previous owner didn't install the retaining clip, he did, if he can rebuild it himself he knows about a retaining clip...but he probably put it in vertically or it accidentally spun enough which allowed it to expand and pop out while under pressure... turn it the opposite way and it'll only get tighter while under pressure. I've seen many clips pop off because of improper install. It doesn't help when the bike is idling to the absolute moon before ever giving it throttle, on a brand new engine with no heat cycles. It's far better for no idle at all and just leave the throttle open enough to keep it from stalling, than it is idling like that... turn it to where it doesn't idle, then turn the screw just enough until its just on this side of stalling, you do not need a high idle. It sounded terrible before it ever grenaded. He revs the piss out of everything, doesn't matter if it's new or not, cold start or hot, just wide open continous blips or idling super high while also giving it wide open blips. I've yet to hear a properly tuned crisp 2 stroke on the channel, yet every time, "it sounds perfect" noooo... I either hear it being way too rich or detonating. Like this he said sounded great, no it didn't. He's a great mechanic and good at diagnosing issues, without a doubt, but jetting and knowing what a properly tuned bike sounds like is not it.. jetting from a piece of paper will get you in the ball park, the fine tuning is done by ear.
@@Odder-BeingPerhaps you guys can post a video with a good audio and explain your process. Not revving a freshly started engine, absolutely. Having a high idle so it doesn't stall also normal. Once it hits operating temp tapping throttle (not redlining) can help seat rings and identify if carb is working as intended. So Joe has plenty of room for improvement, but in his defense I can't hear these noises people speak of unless my phones audio just isn't up to task. So if it sounds normal, doesn't bog, spit, pop, etc., and a fresh plug turns tan after riding an hour isn't his tuning darn close? I would agree with his usual starting procedure and how he breaks in fresh engines would get him talked to if he worked for me. But I get to watch him make mistakes, for free, and get these old machines running and I learn what not to do as well.
FYI, Something I'm sure you know. Top end rebuilds only you need to pull the engine out flush out down inside the crank area with diesel fuel. Work the crank by hand really well (for a few minutes) Turn engine upside down, continue working the crank (round and round) Both directions too. Blow out wit air well Repeat Repeat Repeat Get all metal chunks, spers, flakes out This is a must Good work
WOW! What a blow up! Joe, you should do you next video on this bike on how fast you can rebuilt a motor. No talking, just getting at it. That would be fun to watch.
When someone says they "rebuilt" an engine but it won't start you can bet it was done wrong! So, when you hear rebuilt you should tear the whole thing down to make sure it was done right or ....learn the hard way that it wasn't.
I must say, if this happened to my bike (and I have one of that vintage), I think I'd be inclined to just scrap it and save all the bother. However, it's great to see someone with more patience and enthusiasm at work.
Props to you for putting Humpty Dumpty back together again. Ditto, like many other commenters I would also run away from someone else's rebuild, now you are depending on their level of skills. "I have all these unnecessary parts leftover"
first i am studying to be a mechanic I live in greece so sorry for the bad English so what probably happened was piston bend the valve and then probably because of the high rpm piston gave in and broke that's a nightmare it was a fresh rebuild so something was wrong from the first place from the rebuild re last owner did its only a guess. nice video tho its nice watching video with clean explanations keep up from me I love you videos
Could have been the casting on that side of the piston failed. Once that part of the piston had broken away it would have allowed the wrist pin clip to fall away. It may have simply been an inclusion or void in the casting.
Well said. I think the lesson here is if someone disassembles something and reassembles and it doesn't work you need to completely start over. Take apart everything they touched, clean and inspect. Reassemble adding whatever new parts are needed. I learned the hard way as a major engine and transmission repair tech at dealership that when you skip steps to save time, many times you get a catastrophic failure. I like Joe's content, someday he will learn this lesson including buying an ultrasonic parts cleaner, pressure washer, solvent tank, etc. His rebuilt engines will run, but not last. I hope Joe reads these comments and takes them to heart. @gags730
@@jimw6991 ... we all learned the hard way! If we can get just 1 person to learn the easy way! LOL BTW Great Comment... I have left many posts in the past asking why he does not buy the right equipment. For the life of me I have no idea why this guy does not have an ultrasonic cleaner either.. a large one at that. I have two, and they were not expensive. Heck buy it direct from China if ya have to. I have a pressure washer, and about 6 or 7 years ago I installed a Mini 20 Gallon Electric Water heater for the power washer... You can't beat hot water power washing. The heater was like $250 and I installed it myself.
He needs a proper Bike Lift too! Where he can even sit on a stool and work like a gentleman. With the volume of bikes this man works on, it makes no sense the things he is missing. He is more worried about a spark plug tester. You nailed it with rebuilding. You have to make everything spotless. You could put all the best parts in, spend top dollar but if anything contaminates that engine it will not last. Too many people put engines back together in a dirty environment. It should be like surgery in a hospital when you put it back together and everything needs to be clean. Everything! How many times you see someone all crazy with the assembly lube and oiling everything and yet everything is dirty and contaminated? It's crazy!
Great tear down. I’d love to see the research you do to find good replacement parts. Might make a good filler video for those looking to do their own repair.
It didn't "let go 2 seconds into the ride" it was already letting go before you even swung a leg over it. Im still amazed that you got on the bike and then thrased it when the knock was so clear to hear it was ridiculous. Had you had an once of mechanical sympathy you could maybe have saved it.
If you are rebuilding it. Make sure you put a proper length vent hose on the vent on the back of the valve cover. The older Hondas (not sure if it’s still on newer Hondas) that vent uses the motors pulse to vaporize oil to help lubricant the top end. If it’s to short or not on there at all it will pull dirt in through that vent and ruin the top end.
It's a 4-stroke.....part it out and take your losses. If it was a 2-stroke it would be worth rebuilding and saving. Eventually the manufacturers and everybody will get the memo dirt bikes are meant to be 2-stroke NOT 4-stroke. You can see first hand how unnecessarily complicated this junk turd is after he starts tearing it down. More parts, more complicated....less reliable and more to go wrong and way more money to fix.
@@JohnDoeEagle1 This happend because it wasn't assembled correctly, not because it is a four stroke. A ripped off piston would have caused damage in a two stroke all the same.
@@mementomori4972 You clearly missed the point. Nobody wants a 4-stroke dirt bike. They are overly complicated, junk and throwaway bikes. The EPA pushed them for years however people are starting to get wise the 2-stroke bikes we all had before are superior in every single way.
On one hand its insane how much damage can that little circlip do. I have never heard about this happening in a 4 stroke. On the other hand thats why you should not ride with the engine sounding like a coffee grinder.
Hey Joe I want to say I’ve been watching your videos since you were at 100k subs you’ve come a very long way but very worth it you deserve everything you’ve achieved I learn something from almost every video keep it up! 500k on the way!
Last summer I bought a YFZ450 from a guy. Had the same exact thing happen to him. Web around the wrist pin let go. I don't know why but I got it cheap lol. Sourced OEM crank, cylinder and a Wossner piston with anodizing - actually starting the rebuild this weekend. It should be good to go after I'm done with it. I have nothing against Wiesco, I just decided Wossner - took a while to come in. Still going to split the cases and clean, replace all the bearings so long as I'm in there - be new when done.
You s*ck , i have used vertex in 5 dirt bikes and no problems runs f*king good man no smoke, here in the video it was a mistake of the guy who rebuilt the engine and didn't install the pin from the piston bolt correctly
I had a wrist pin come out on a 1965 BMW R-27. Didn't bend the connecting rod but the wrist pin cut two 68mm long transfer ports (not good in a four stroke). Anyway, I got away with a cylinder, wrist pin, two clips and a piston pin. Funny thing is that it ran me home (150 miles) and just kept getting slower and smokier. This happened in 1970, so parts were readily available at the Sacramento BMW dealer..
I can tell you what happened with 100% certainty as I have seen this before what happened was whoever rebuilt it either forgot to put one of the wrist pin clips in or it wasn't put in correctly the pin walked its way out of the one pin bore and then once that happens there's so much stress on the one side of the pin bore it will break and bend the rod at the same time as the load is only on one side of the rod bending it with 100% certainty that is absolutely what happened there clearly someone put it together that did not know what they were doing
Exactly I soon as he said the seller rebuilt the top & bottom half and couldn't get it to start I was like oh shit someone who didn't know what they were doing rebuilt it that's never good.
I agree with everyone else someone was in a big hurry putting that engine back together.. & failed to do it correctly.! wow too bad.! looked like a nice bike.!
Liquid cooling is wonderful, but after seeing this if I ever got another bike it would need to be air cooled and possibly just two valve. Yeah, I'm an old luddite. I like simplicity in most things. Different kinds of technology has always been my work, but there is something therapeutic about simple as I get older. Feels more like fine art in its own sort of elegance. 😊
WOW!! Quite a mess there, Joe! I think I'd agree with jeredalmedia 1880-the wrist pin clip didn't seat on that one side. You have to pay attention to the small details, which will save your attention from being distracted by the disaster to follow, if you don't.
My guess is a missing circlip to hold the gudgeon pin in place. This allowed the piston to float free and lots of other fun and games within the engine!!
I knew right away from the first video that the thingamabob next ro the whatchacallit broke rightaway buuutttt i didn't say anything because i didn't want to be a know-it-all.Love your videos Joe!!
Great stuff and I’d agree re the gudgen pin (as we Brits call it ) came loose after the circlip came loose . I have seen a piston loose like this when riding Enfield in the Himalayas . On one that was running rough the crown of the piston had broken away from the body of the piston !! It ran badly but was fixed by putting a new piston in . Those bikes are tough , which is what you need in those remote areas . Love your stuff
From the last video, there were 50 professional small engine builders that declared "but the timing chain is slapping the case", "Im deaf in both eyes, and blind in my left ear, and my hearing eye dog told me the timing chain was on upside down!"
Yes, you guess like I did, but until you take it apart you won't know. I'm not engine builder, but I've rebuilt a few and also snapped a cam chain. Sounded just like that. Lucky I was kicking the motor slow It started and then popped. It snapped and wadded up. We pushed it to a road and my buddy used his foot on my muffler to push me back to the truck.
A very wise technician once told me you always have to find the reason for failure or else its likely to happen again. Pistons generally don't "let loose". Its kinda obvious a wrist pin circlip either was installed incorrectly or not at all.
I have watched your videos for a long time and enjoy them. Thank you. I've never seen a piston give away like that. So like the other grease monkeys I say it has to be the wrist pin clip was not installed. Good job again my friend.
Man, you're a cool cucumber, Joe! It has to be frustrating when, while all if not most of your repairs are fruitful and work, to have to trust someone else's. I mean, If I were you, I'd be like, "If anyone other than the Japanese factory worker who assembled this bike has touched it (besides ME of course), I'm OUT!
@@aidanlyons1155 That's where I'd say we have a difference of opinion. 'Shadetree mechanics' usually just work on their own bikes which might number 2 or 3 and only when they require service. Joe has worked on hundreds of bikes over the course of his channel. Gaining a skill requires repetition and trial and error in different situations. Check. Technician just means a person, who has acquired skills in a certain field, is proficient in that field. Check. In conclusion, the last time I checked skilled technicians can screw engines up too. Just not very often. Check and mate. 😁👍
What a video! You have a great attitude as well towards seeing something that can be devastating. I hope you had the funds to rebuild it because at this point you would have a new engine that would last many years. I sure hope I can find a video of you putting it back together
"What the hell happened here" I tell you Joe, you revved it to the moon when the engine made knocking sounds so loud you could hear it wearing ear mufflers.
If the Piston pin retaining clip came loose, the Piston pin would have slid against the cylinder and scored it! The pin would not have come out. I believe the piston had a manufacturing fracture.
Good teardown, I suspect failure was HYDROLOCK your evidence was there you picked up on it but didn't see that as your issue. Coolant got into the cylinder, bad gasket ? Looking forward to the rebuild. Keep up the good work.
I didn’t hear anywhere that said he was the one that rebuilt it, just said it was rebuilt. Could have had it done, other than the 1 failure it seemed to be put together correctly.
The side of the wrist pin bore that is still there had its circlip missing or come out and wrist pin slid over and came out of its opposite bore and thats why that side got ripped out from under the piston. On the bright side you dont have to split the case just because of debris removal. You have to replace the crank so the cases have to be split. Now is the time to upgrade the clutch, crank, rod, piston and rings and cylinder.
He wasn’t lied to lol he simply left a part out and had no idea. He never had it running with that carb like that. You could hear it eating itself apart on the first startup should have stopped there.
at 18:00 i figured it was a broken connecting rod... i was almost right lmao sounded almost identical. i have also never seen it break like this, youre lucky that rod didnt go straight thru the case... although i guess that mainly happens when you snap the rod so its able to tilt completely sideways and punch thru the case, not just yank it out of the piston lol its too long to jam sideways
Could be a wrist pin clip. Or an improperly sized piston. In order to pull that piston apart at the wrist pin it failed on a downstroke. Once the piston is loose all bets are off.
I think the casting on the piston where it attaches to the rod failed because it didn't let loose until you tried to ride it so when it had a load on it is when that part failed. You can tell Joe has rebuilt so many motors he can take them apart and know where every gear goes. When this bike is rebuilt its going to be a good one. Hope he can get 3k for it when he sells it to make some money for all that work.
Joe I’ve been watching you a good while and I still can’t understand how you couldn’t hear in the last video that the timing chain was slapping the case ? Then in this video you’re messing around pulling the side cases when you know and so does anyone with any mechanical background knows full well that the piston had slammed the valves and the top end would be destroyed.it feels like you’re just dragging it out acting like you didn’t know what the problem was just to get more content! It’s pretty sad tbh as I like your videos but this crf series just sucks
That's a shame, gotta really look at the head, those guides and the surrounding casting have taken a hit, you probably won't know for sure until you start the lap the new valves if the head is still good, that sucks Joe, good luck with it, looking forward to seeing how this plays out
I thought that sound when it locked up was familiar. 1985 Sears Point Raceway. AFM Formula Singles class race. just finished turn 8A and flopped the bike over for 8B at the same time up shifted and that same sound happened. The connecting rod let go and engine locked up tight in a fraction of a second. The rest of the seconds was the sound of me sanding down my leathers sliding down the track. You'll never forget that sound Joe. Sorry for the crappy luck.
the seller who rebuilt it, forgot to fully install the wrist pin retaining clip, the wrist pin worked its way out, got caught on the bottom of the cylinder bending the connecting rod and cracking the piston. that is why only half of the piston is cracked off
Absolutely Agree
That's what I think, seller installed one retaining clip and forgot to install the other one.
I agree. I've seen it before. You wouldn't think a little clip would do so much damage, but it will tear a motor to pieces.
Yep, explains the damage to piston and cylinder on one side.
Sorry I didn't see your comment at the time I posted my comment I've seen this before most likely failure to install wrist pin clip or it could have had spiral clips and wasn't installed correctly
As a former longtime MC tech, I NEVER EVER trust an amateur’s work. It’s always a good idea to revisit any work a previous owner did to avoid issues like this.
I do the same :) Trust but verify!
Before I looked at the comments I had come to the exact same conclusion that the wrist pin clip had not been installed on the one side. I'll wager that you won't find any evidence of the second clip in the motor. Thanks for your content, I love it
I bet the other retaining clip is still in the piston
After watching this entirely, I'm willing to bet that one of the wrist pin clips wasn't fully seated. Whoever rebuilt this engine forgot to listen for the snap.
or properly seated .. see my comment below..
i totally Agree w/ you . Wrist Pin FAILURE !!! ''''''''''
Or was never installed.
Ring debris should still be in the case.
Yeah your theory lines up with the evidence. Thinking the same thing at this point
I agree
That result is every motor enthusiast's worst nightmare. Good diagnosis and video! Looking forward to watching the rebuild.
Its amazing how you can laugh after your bike blows up, Id be swearing like a sailor! I envy you man, keep up the hard work! Love the vids! 👍
You can see on the bottom right side of cylinder wall where the Piston pin scraped and caused piston to break. Like others have said it looks like the wrist pin clip wasn't installed all the way and fell off causing pin to slide out catching cylinder wall and or just caused piston pin journal to break.
Had bent rod situation about a year ago, could find parts, European junk. Heated rod a bit, used the press and got it back straight as an arrow. Ran fine after, still running today!! Crazy, was a hail Mary but it frkn worked. Setting up to straighten was the pain.
Nice. Did you Hail Mary the crank without a truing stand?
The crank is from Hot rods. I rebuild a yz250f and the rod had the same id system. If you search for hot rods connecting rod 616 you’ll find visibly identical cranks for the crf250r.
It's nice to read these comments, which seem to be 100% accurate on the reason the engine failed. It's unfortunate when a newly rebuilt engine fails in such a short amount of time. But, knowing why it happened is priceless knowledge. Love and appreciate your content.
I agree with other commenters the wrist pin was likely floating in there before you even got the bike started. Enjoy the videos, great work.
Here's why I always double-check customer work. Admittedly, finding a misplaced wrist pin clip would've been impossible to see without a complete teardown, which I likely wouldn't have done, so I would've had the same result as Joe. I always hated dealing with other people's lack of mechanical knowledge.
He makes his money on other people's lack of ability , but he didn't win on this one !!
Thanks Joe for taking one for the team!
@@craigdalzell2908 Not at all. If I were him I wouldn't bother with this engine and I'd just buy a replacement one instead. I'm sure it would be much cheaper and he wouldn't have to spend who knows how many hours tearing it down completely. He'd have to so he could get all of those loose metal fragments out of the engine entirely. I would never take the chance of just fishing out what I could see and cross my fingers for the rest.
@@stkyfngrszmooth And in the end the customer would blame you.
@@mementomori4972 Every time.
If I had to guess the E clip came off and let the pin slide over to the wall and break one ear. Or maybe there was only one E clip. I am 67 years old and have been working on motorcycles for 55 years.And I still learn stuff from you all the time. Keep up the good work. And I wish when I was young I would have had the job you do.👍
I've owned motorcycles all my life and I have never seen that happen before !!!!!! Just because it's new doesn't name that is a good part !!
How to say a lot without saying nothing at all😅
I've seen this before. They either forgot one or both of the wrist pin 35:45 clips. Or did not get the clip properly into the groove. When the wrist pin slides over it puts all the stress on one eyelet of the bottom of the piston and that's why it broke.
Im 49 this is why i prefer simple two stroke engines no timing chains or camshafts. 👍🇺🇸
@@lesoram6236 were talking about motor cycles 👍
@@lesoram6236 I did for 15 years
I'm 55 and and won't buy a new 4 stroke. 2 strokes are cheaper(especially pre nikasil).
@@lesoram6236do you drive a 4 stroke car?? O ok 😂
Same you can’t beat them. So simple and much faster plus they sound amazing
wrist pin clip wasnt snapped in !!! YOU GOT LUCKY !!! engine immediately stopped instead of metal chunks taking out the cases and everything else!! 😃👍👍👍👍👍👍👍👍
Great video, with lots of learning moments. 😭No riding today. Keep working on the problem, your patience and skills are amazing.
People saying the previous owner didn't install the retaining clip, he did, if he can rebuild it himself he knows about a retaining clip...but he probably put it in vertically or it accidentally spun enough which allowed it to expand and pop out while under pressure... turn it the opposite way and it'll only get tighter while under pressure. I've seen many clips pop off because of improper install.
It doesn't help when the bike is idling to the absolute moon before ever giving it throttle, on a brand new engine with no heat cycles. It's far better for no idle at all and just leave the throttle open enough to keep it from stalling, than it is idling like that... turn it to where it doesn't idle, then turn the screw just enough until its just on this side of stalling, you do not need a high idle. It sounded terrible before it ever grenaded. He revs the piss out of everything, doesn't matter if it's new or not, cold start or hot, just wide open continous blips or idling super high while also giving it wide open blips. I've yet to hear a properly tuned crisp 2 stroke on the channel, yet every time, "it sounds perfect" noooo... I either hear it being way too rich or detonating. Like this he said sounded great, no it didn't.
He's a great mechanic and good at diagnosing issues, without a doubt, but jetting and knowing what a properly tuned bike sounds like is not it.. jetting from a piece of paper will get you in the ball park, the fine tuning is done by ear.
This comment is ace 💯 Exactly how i see Joe. A couple times i thought to my self, this dude must be deaf for real.
@@Odder-BeingPerhaps you guys can post a video with a good audio and explain your process. Not revving a freshly started engine, absolutely. Having a high idle so it doesn't stall also normal. Once it hits operating temp tapping throttle (not redlining) can help seat rings and identify if carb is working as intended. So Joe has plenty of room for improvement, but in his defense I can't hear these noises people speak of unless my phones audio just isn't up to task. So if it sounds normal, doesn't bog, spit, pop, etc., and a fresh plug turns tan after riding an hour isn't his tuning darn close?
I would agree with his usual starting procedure and how he breaks in fresh engines would get him talked to if he worked for me.
But I get to watch him make mistakes, for free, and get these old machines running and I learn what not to do as well.
FYI,
Something I'm sure you know.
Top end rebuilds only you need to pull the engine out flush out down inside the crank area with diesel fuel. Work the crank by hand really well
(for a few minutes)
Turn engine upside down, continue working the crank
(round and round)
Both directions too.
Blow out wit air well
Repeat Repeat Repeat
Get all metal chunks, spers, flakes out
This is a must
Good work
If there are metal chunks or flakes, you need to split the cases and clean everything properly. Not just “flush it out with diesel fuel”
Only if it's a 2-stroke.
If it's a 4-stroke - they have oil and coolant passages that might be clogged and/or screen filters clogged too.
Wrist pin clip fell out is my first thought
Soon as you started it in the field I could hear it knocking like a madman. It was letting go but you rode it & finished it off
WOW! What a blow up! Joe, you should do you next video on this bike on how fast you can rebuilt a motor. No talking, just getting at it. That would be fun to watch.
Never happen. Must talk and do it the hard way. Watch Allen Millyard.
See Mad Marc for no talking refurbishment of two strokes
when it let go i definently thought the timing chain broke, thats pretty crazy.Thanks for the videos love how you break things down!!!
When someone says they "rebuilt" an engine but it won't start you can bet it was done wrong! So, when you hear rebuilt you should tear the whole thing down to make sure it was done right or ....learn the hard way that it wasn't.
I must say, if this happened to my bike (and I have one of that vintage), I think I'd be inclined to just scrap it and save all the bother. However, it's great to see someone with more patience and enthusiasm at work.
Dude, you're deep down in the bones a real work horse. You could take 3 months off and I'd still be here playing catch up on videos. haha
Props to you for putting Humpty Dumpty back together again. Ditto, like many other commenters I would also run away from someone else's rebuild, now you are depending on their level of skills. "I have all these unnecessary parts leftover"
first i am studying to be a mechanic I live in greece so sorry for the bad English so what probably happened was piston bend the valve and then probably because of the high rpm piston gave in and broke that's a nightmare it was a fresh rebuild so something was wrong from the first place from the rebuild re last owner did its only a guess. nice video tho its nice watching video with clean explanations keep up from me I love you videos
I totally agree. The way the piston was broken on one side and the connecting rod was bent. And only one wrist pin clip was found in the engine
Could have been the casting on that side of the piston failed. Once that part of the piston had broken away it would have allowed the wrist pin clip to fall away. It may have simply been an inclusion or void in the casting.
I’m gonna say it fell out, it’s a junk vertex piston so could be ur hypothesis too
Never trust some one's engine rebuild. I learned from years of experience working at a dealer ship.
I fixed some things but have this box of parts
Nailed it
Especially after they 'Rebuild it' and can't get it running ever again. So much so that they give up and sell the bike. The wreaks of inexperience!
Well said. I think the lesson here is if someone disassembles something and reassembles and it doesn't work you need to completely start over. Take apart everything they touched, clean and inspect. Reassemble adding whatever new parts are needed.
I learned the hard way as a major engine and transmission repair tech at dealership that when you skip steps to save time, many times you get a catastrophic failure. I like Joe's content, someday he will learn this lesson including buying an ultrasonic parts cleaner, pressure washer, solvent tank, etc. His rebuilt engines will run, but not last.
I hope Joe reads these comments and takes them to heart.
@gags730
@@jimw6991 ... we all learned the hard way! If we can get just 1 person to learn the easy way! LOL
BTW Great Comment... I have left many posts in the past asking why he does not buy the right equipment.
For the life of me I have no idea why this guy does not have an ultrasonic cleaner either.. a large one at that. I have two, and they were not expensive. Heck buy it direct from China if ya have to.
I have a pressure washer, and about 6 or 7 years ago I installed a Mini 20 Gallon Electric Water heater for the power washer... You can't beat hot water power washing. The heater was like $250 and I installed it myself.
He needs a proper Bike Lift too! Where he can even sit on a stool and work like a gentleman.
With the volume of bikes this man works on, it makes no sense the things he is missing. He is more worried about a spark plug tester.
You nailed it with rebuilding. You have to make everything spotless. You could put all the best parts in, spend top dollar but if anything contaminates that engine it will not last. Too many people put engines back together in a dirty environment. It should be like surgery in a hospital when you put it back together and everything needs to be clean. Everything!
How many times you see someone all crazy with the assembly lube and oiling everything and yet everything is dirty and contaminated? It's crazy!
Great tear down.
I’d love to see the research you do to find good replacement parts. Might make a good filler video for those looking to do their own repair.
It didn't "let go 2 seconds into the ride" it was already letting go before you even swung a leg over it. Im still amazed that you got on the bike and then thrased it when the knock was so clear to hear it was ridiculous. Had you had an once of mechanical sympathy you could maybe have saved it.
Have to agree with you. Noise was quite evident when it was running...
If you are rebuilding it. Make sure you put a proper length vent hose on the vent on the back of the valve cover. The older Hondas (not sure if it’s still on newer Hondas) that vent uses the motors pulse to vaporize oil to help lubricant the top end. If it’s to short or not on there at all it will pull dirt in through that vent and ruin the top end.
All these 4-stroke MX bikes are throwaway engines.
Part it out and cut your losses, Joe.
agreed
I mean if you’re not mechanically inclined then sure.
It's a 4-stroke.....part it out and take your losses. If it was a 2-stroke it would be worth rebuilding and saving. Eventually the manufacturers and everybody will get the memo dirt bikes are meant to be 2-stroke NOT 4-stroke. You can see first hand how unnecessarily complicated this junk turd is after he starts tearing it down. More parts, more complicated....less reliable and more to go wrong and way more money to fix.
@@JohnDoeEagle1 This happend because it wasn't assembled correctly, not because it is a four stroke. A ripped off piston would have caused damage in a two stroke all the same.
@@mementomori4972
You clearly missed the point. Nobody wants a 4-stroke dirt bike. They are overly complicated, junk and throwaway bikes. The EPA pushed them for years however people are starting to get wise the 2-stroke bikes we all had before are superior in every single way.
Wow! I did not expect it to let loose like that. I thought the timing chain broke, but man was I wrong.
On one hand its insane how much damage can that little circlip do. I have never heard about this happening in a 4 stroke.
On the other hand thats why you should not ride with the engine sounding like a coffee grinder.
Hey Joe I want to say I’ve been watching your videos since you were at 100k subs you’ve come a very long way but very worth it you deserve everything you’ve achieved I learn something from almost every video keep it up! 500k on the way!
Clip was not put in all the way and it fell out and the the wrist pin backed out. Then Boom.
Last summer I bought a YFZ450 from a guy. Had the same exact thing happen to him. Web around the wrist pin let go. I don't know why but I got it cheap lol. Sourced OEM crank, cylinder and a Wossner piston with anodizing - actually starting the rebuild this weekend. It should be good to go after I'm done with it. I have nothing against Wiesco, I just decided Wossner - took a while to come in.
Still going to split the cases and clean, replace all the bearings so long as I'm in there - be new when done.
Vertex cast piston, Italian engineering =)
You s*ck , i have used vertex in 5 dirt bikes and no problems runs f*king good man no smoke, here in the video it was a mistake of the guy who rebuilt the engine and didn't install the pin from the piston bolt correctly
Yup..... retainer didn't seat and the pin walked out enough have the load all on the broke side. Good stuff!!
That sound of a four stroke seizing is as fear inducing as the thought of erectile dysfunction.
The screeching sound of metal against metal coming from the cylinder is far worse.
@@Hurdy_Gurdy_Mushroom_Man Yes! That's the sound that makes you play some Taylor Swift just to stop the pain in your ears.
It's even worse when you hear a two stroke seizing up
@@jeredalmeida1880I'd rather listen to the engine exploding over and over.
@@stkyfngrszmooth 🤣 It's like the engine keeps making the same mistakes and writing a song about it every time.
I never seen that happen, that is such a bummer. I would change the main bearings too, just to be sure. Great video again, Big Up!
No question, first failure was piston pin retaining clip coming loose
I had a wrist pin come out on a 1965 BMW R-27. Didn't bend the connecting rod but the wrist pin cut two 68mm long transfer ports (not good in a four stroke). Anyway, I got away with a cylinder, wrist pin, two clips and a piston pin. Funny thing is that it ran me home (150 miles) and just kept getting slower and smokier.
This happened in 1970, so parts were readily available at the Sacramento BMW dealer..
I can tell you what happened with 100% certainty as I have seen this before what happened was whoever rebuilt it either forgot to put one of the wrist pin clips in or it wasn't put in correctly the pin walked its way out of the one pin bore and then once that happens there's so much stress on the one side of the pin bore it will break and bend the rod at the same time as the load is only on one side of the rod bending it with 100% certainty that is absolutely what happened there clearly someone put it together that did not know what they were doing
Exactly I soon as he said the seller rebuilt the top & bottom half and couldn't get it to start I was like oh shit someone who didn't know what they were doing rebuilt it that's never good.
Agree. Piston pin clip/s came out. Seen that before. Cylinder tells the story
I could conceraningly hear it knocking when you started it up
I agree with everyone else someone was in a big hurry putting that engine back together.. & failed to do it correctly.! wow too bad.! looked like a nice bike.!
Looks like a clip popped out and the pin slid to one side and hit the cylinder and bent the rod.
Liquid cooling is wonderful, but after seeing this if I ever got another bike it would need to be air cooled and possibly just two valve. Yeah, I'm an old luddite. I like simplicity in most things. Different kinds of technology has always been my work, but there is something therapeutic about simple as I get older. Feels more like fine art in its own sort of elegance. 😊
Early four stroke MXers> HAND GRENADE and not cheap to fix
WOW!! Quite a mess there, Joe! I think I'd agree with jeredalmedia 1880-the wrist pin clip didn't seat on that one side. You have to pay attention to the small details, which will save your attention from being distracted by the disaster to follow, if you don't.
The real carnage starts around the 27:00 mark for those impatient to know.
New rod, piston, cylinder, and valves. Clean it up good, lap in new valves and put it all back together and should be fine. Good video
If you don't have a borescope camera yet, it's time to get one. 🙂
My guess is a missing circlip to hold the gudgeon pin in place. This allowed the piston to float free and lots of other fun and games within the engine!!
Jkjk love your vids and constant content brother keep up the good work
I knew right away from the first video that the thingamabob next ro the whatchacallit broke rightaway buuutttt i didn't say anything because i didn't want to be a know-it-all.Love your videos Joe!!
This is why they say that 99% of people can’t build a motor lol
Great stuff and I’d agree re the gudgen pin (as we Brits call it ) came loose after the circlip came loose . I have seen a piston loose like this when riding Enfield in the Himalayas . On one that was running rough the crown of the piston had broken away from the body of the piston !! It ran badly but was fixed by putting a new piston in . Those bikes are tough , which is what you need in those remote areas . Love your stuff
From the last video, there were 50 professional small engine builders that declared "but the timing chain is slapping the case", "Im deaf in both eyes, and blind in my left ear, and my hearing eye dog told me the timing chain was on upside down!"
That's what my laundry basket said too....
@@biker6991🤣🤣🤣🤣
Yes, you guess like I did, but until you take it apart you won't know. I'm not engine builder, but I've rebuilt a few and also snapped a cam chain. Sounded just like that. Lucky I was kicking the motor slow It started and then popped. It snapped and wadded up. We pushed it to a road and my buddy used his foot on my muffler to push me back to the truck.
Yep i commented and thought it was cam chain...own it.
Its good to learn.
There was a strange noise emanating long before the 'blow up' though.
A very wise technician once told me you always have to find the reason for failure or else its likely to happen again. Pistons generally don't "let loose". Its kinda obvious a wrist pin circlip either was installed incorrectly or not at all.
You should have probably checked the other guys work before starting it. He apparently did not have a clue what he was doing!
He never checks he’d rather it blow up so he has a video to post
Much like the buyer. Never see any of this junk sold “running perfectly”
Sofa quarter backing
I have watched your videos for a long time and enjoy them. Thank you. I've never seen a piston give away like that. So like the other grease monkeys I say it has to be the wrist pin clip was not installed. Good job again my friend.
Man, you're a cool cucumber, Joe! It has to be frustrating when, while all if not most of your repairs are fruitful and work, to have to trust someone else's. I mean, If I were you, I'd be like, "If anyone other than the Japanese factory worker who assembled this bike has touched it (besides ME of course), I'm OUT!
Joe isnt exactly a skilled technician either, just a shade tree mechanic like the rest of us. He can screw up an engine too lol.
@@aidanlyons1155 That's where I'd say we have a difference of opinion. 'Shadetree mechanics' usually just work on their own bikes which might number 2 or 3 and only when they require service. Joe has worked on hundreds of bikes over the course of his channel. Gaining a skill requires repetition and trial and error in different situations. Check. Technician just means a person, who has acquired skills in a certain field, is proficient in that field. Check. In conclusion, the last time I checked skilled technicians can screw engines up too. Just not very often. Check and mate. 😁👍
It makes great content though !
What a video! You have a great attitude as well towards seeing something that can be devastating. I hope you had the funds to rebuild it because at this point you would have a new engine that would last many years. I sure hope I can find a video of you putting it back together
"What the hell happened here" I tell you Joe, you revved it to the moon when the engine made knocking sounds so loud you could hear it wearing ear mufflers.
🤣
I heardit and I am in Scotland!!! 😂😂😂
@@biker6991 Aye, it was loud as fook here in Aberdeen
@@k-mc94 "Curse me kilts, laddy!"
@@jeredalmeida1880 😂
Excellent video, this was really interesting to watch. Bummer on the carnage in that motor, what a mess. Thanks for the video loving the content.
Joe in last video it was rattling like a crack head locked in boot of car 🙈🙄
Other guy forgot to put a clip in the wrist pin...
Would be interesting to see what the ring end gap was. Maybe it caused the piston to seize in the bore when the engine heated up?
If the Piston pin retaining clip came loose, the Piston pin would have slid against the cylinder and scored it! The pin would not have come out. I believe the piston had a manufacturing fracture.
Good teardown, I suspect failure was HYDROLOCK your evidence was there you picked up on it but didn't see that as your issue. Coolant got into the cylinder, bad gasket ? Looking forward to the rebuild. Keep up the good work.
So a guy who rebuilt the entire engine couldn't fix a dirty carburetor? That should have been a red flag
I was thinking the same thing…
I didn’t hear anywhere that said he was the one that rebuilt it, just said it was rebuilt. Could have had it done, other than the 1 failure it seemed to be put together correctly.
@@vincemarshall9520 Front brake line isnt mounted right that is a big red flag they have no idea what they doin
The side of the wrist pin bore that is still there had its circlip missing or come out and wrist pin slid over and came out of its opposite bore and thats why that side got ripped out from under the piston. On the bright side you dont have to split the case just because of debris removal. You have to replace the crank so the cases have to be split. Now is the time to upgrade the clutch, crank, rod, piston and rings and cylinder.
Sellers will always lie, just to sell the item.
More likely that they had no idea what they were doing rebuilding the motor, doubt they knew the issue.
You're like a surgeon with that motor . Nice work.
Ripped off and lied to again Joe.
He wasn’t lied to lol he simply left a part out and had no idea. He never had it running with that carb like that. You could hear it eating itself apart on the first startup should have stopped there.
29:10 I’m guessing the rod snapped and it’s a hot rod crank or a wiseco. I like hot rods but not for super high compression motors
This whole situation is why two strokes are King 👑 always
👍
at 18:00 i figured it was a broken connecting rod... i was almost right lmao sounded almost identical. i have also never seen it break like this, youre lucky that rod didnt go straight thru the case... although i guess that mainly happens when you snap the rod so its able to tilt completely sideways and punch thru the case, not just yank it out of the piston lol its too long to jam sideways
He had the wrong piston in this motor
Could be a wrist pin clip. Or an improperly sized piston. In order to pull that piston apart at the wrist pin it failed on a downstroke. Once the piston is loose all bets are off.
Thats why god gave us the ability to perform a engine warm up so this doesn't happen.
That bike is going to have PTSD now.
Bollox.
I think the casting on the piston where it attaches to the rod failed because it didn't let loose until you tried to ride it so when it had a load on it is when that part failed.
You can tell Joe has rebuilt so many motors he can take them apart and know where every gear goes. When this bike is rebuilt its going to be a good one. Hope he can get 3k for it when he sells it to make some money for all that work.
This is a classic reason why I shy away from buying a 4 stroke.
It's also a classic reason why I shy away from buying a 2 stroke.
@@nednelp9051 That same damage on a 2 stroke would've cost half the money to fix.
@@AnthonyRufo-rc1zmyet you’d do it 4x more.
Good troubleshooting Joe! Personally I’d rather jump off a bridge than work on a early CRF or YZF
Joe I’ve been watching you a good while and I still can’t understand how you couldn’t hear in the last video that the timing chain was slapping the case ? Then in this video you’re messing around pulling the side cases when you know and so does anyone with any mechanical background knows full well that the piston had slammed the valves and the top end would be destroyed.it feels like you’re just dragging it out acting like you didn’t know what the problem was just to get more content! It’s pretty sad tbh as I like your videos but this crf series just sucks
The crf250 send and mend series.... Stuff happens. Looking forward to the rebuild Joe !
1 min one view bro you fell offff
@@minnesotatomcatPretty sure he's joking. I love this channel and I'm sure he's a big fan too.
Joe buys views. Common practice
Bot!🤫🤐🤐😫😫😫💀☠️💀💩💩🤡🤡👎👎
Pyro?😂
Gnarly! I only saw one wrist pin clip....wonder if the builder forgot the second one.
That's a shame, gotta really look at the head, those guides and the surrounding casting have taken a hit, you probably won't know for sure until you start the lap the new valves if the head is still good, that sucks Joe, good luck with it, looking forward to seeing how this plays out
I thought that sound when it locked up was familiar. 1985 Sears Point Raceway. AFM Formula Singles class race. just finished turn 8A and flopped the bike over for 8B at the same time up shifted and that same sound happened. The connecting rod let go and engine locked up tight in a fraction of a second. The rest of the seconds was the sound of me sanding down my leathers sliding down the track. You'll never forget that sound Joe. Sorry for the crappy luck.
"You'll never forget that sound Joe" O but Joe does because he is fricking deaf.
😂I predicted the wrist pin in some manner ❤ I was close! Great videos Joe and as always keep it up
Think its sp tools makes a adapter to put on you extensions and sockets for hammering on so you don't trash them. It's pretty cool.
Thanks for the vod !
WAITING FOR UPDATE ON THIS I JUST GOT A 2007 MODEL AND THIS TEAR DOWN HELPS SO MUCH
great video as always. Joe, dont what your "day job" is but it must be a good one. these things are pricey to fix.