My yamaha DT125r had lubrication via oil pump and i changed it to oil/gas mixture because the plastic gear always broakes and then my bike gets dry. A huge problem on any yamaha DT
The exhaust bridge gets a lot of heat and tends to expand into the cylinder and touch the piston when under load and rpm which is the same area that got damage on yours, the bridge on my 500 has been sanded back a bit to allow for expansion, it will rev as high and as long as I want and no troubles with the engine, same piston for five years, just an idea
Exhaust bridge probs reminds me of the SC500 Yamahas my two friends had - seemingly having the same problem. We tried drilling a small hole in the piston skirt inline with the bridge to keep the bridge cooler. I think we got the idea off either my TM400 or RM370, but it's been too long a time to recall exactly
+ViperACR01 i had an 1983 cr250 with an exhaust bridge, Wiseco's instruction sheet said to drill a small hole (can,t remember the size, or if they said one or two holes, or the location ), we didn't have any issues afterward. I bought the bike with an exhaust side meltdown.
I had a 1978 Penton 250 that was the first bike I ran across with a piston hole for the exhaust bridge. Was freshening the top end for an up coming weekend enduro and if i recall they wanted a .040 hole in the exhaust skirt for the bridge. Unfortunately I made a mistake and drilled it on the intake side (crap!!). Enduro this week end and another piston a week away....went ahead and put it together...I mean a .040 hole in the intake skirt couldn't make that much difference, right? WRONG WRONG WRONG!! Turned a 40 horse mudslingin rooster into a slug that wouldn't pull a sick whore off a tricycle.
No when you let your throttle go you cilinder gets pretty mutch no oil at all and when you leave it in gear your cilinder will stay at high rpm's with low fuel & oil and when you clutch it it ill drop at rpms reely quickly to stationary so it gets all that it needs so to say
Actually , him wailing the throttle and leaving the tire to spin while he completely shuts off the throttle is not very good for your 2 stroke. The tire has the momentum from the full throttle dyno pull most likely 5th gear lol. And to just shut off the throttle slide with all that momentum you will be winding the shit out of your motor. (pretty much engine braking on a 2 stroke) Yea, definitely could of been prevented just by pulling in clutch to shut the back wheel momentum off from the crank. Lol, i'm 15 and i know this come on. Also it looks like hes running like 50:1 premix with little to no smoke. if your trail riding thats perfect but not for dyno runs; lack of oil was for sure his problem. please inform me on how i "couldn't be more wrong." LOL You should probably stick to R/C cars lol.
Its a simple reason for seizing, any rider should know if you take any two stroke to high rpm and then chop the throttle without clutching all the fuel/oil that lubricates the motor is taken away but because the clutch is still enguaged and its in gear the need for fuel/oil remains the same but closing the throttle cuts the supply creating a super lean air/fuel condition causing it to seize. Had he pulled the clutch in when the throttle was chopped would prevent it, same can happen on huge sand dunes when people haul ass downhill and chop the throttle, cause its still in gear forcing high rpms but no fuel/oil can get in to cool and lube things. Only happens on two strokes that need fuel/oil for lubrication.
Here is a pro tip. After a long, high RPM run with a two stroke, push the kill switch while holding the throttle wide open for a few seconds, cools the cylinder and piston down. Thats an old pro desert racing trick.
Ive never heard this before, that's really a legit trick? what does holding the throttle wide open while killing the motor for a few sec do? Im super curious about this now.... And Thanks for the tip!
It lets the fuel/oil/air mixture continue to flow into the motor without being burnt off, so it cools and lubes the piston and cylinder, preventing this exact thing from happening.
I have a friend who used to have a handlebar choke cable. He'd give a shot of choke at the end of long straights to cool things down before heading back into the bush.
its a two stroke engine. It is not lubricating itself while off throttle and at this revs god i can only imagine how dry it must have been inside... lol
Yes, Eric Elder, stinger section. Do you know which part of the expansion chamber that is? Do you understand how that affects the character of a twostroke engine and the powerband together with exhaust temp?
Cykelen sitter fast med framhjulet så helly felly, man ska ha en broms på rullen. Bromsar du med bakbromsen så glöder skivan innan rullen stannar. Motorbrom på 2-takt är samma sak som ingen oljetryck på 4-takt, Jag körde den här cykelen i min bänk med 2 olika pipor och det hände inget.
Sadly most dyno shops never do. They usually have the owner of the vehicle sign a waver that makes it so they have no responsibility for engine damage. Atleast here in the states every dyno has you sign papers and if you're not willing to they will not tune your car or bike.
WRider Thats another thing... alot of them claim only a certified technician for the companies Dyno is allowed to use vehicles on it. I've tried to say the same thing where i asked if i could just drive my vehicle on the dyno. and they claim that if youre not trained in the field of driving on a dyno you can destroy it. Its sort of a lose lose with tunning .. I mean yeah they can squeeze some more power out. But at the end of the day they make you pay ridiculous prices and if they blow your motor its on you.
No cooling fan? Lean oil to fuel ratio? Ive run my CR500 for years on 100 octane gas at 40:1 with Klotz castor, engine brake, and have never had any engine problems whatsoever on any of my bikes, for that matter. Bore & hone that cylinder out to the next oversize, chamfer the port windows and get a freshly forged Wiseco in there, mix up some good stuff at 40:1 and go at it with a cooling fan (or 2) blowing through those radiators. You might want to check out your pipe & stinger dimensions too..
I thought you were supposed to use a dial indicator or piston stop when you set the timing and not just "eyeball it" And was the carb loose or was he rejetting it cause that would def make it run lean along with just chopping the throttle at wot
It seized because he shut the throttle and let it overrun with no fuel being fed into the engine. It runs on premix so the engine only gets lubricated if the throttle is open. In the old days, loads of bikes would seize at the end of the 1.5 mile start straight at Weston Supermare beach race. ...They would go flat out in top, shut off, seize.....go home....Thats why 4 strokes are better for high speed deceleration.
Suprised they expected it to not lock up. All the oil a 2 stroke gets is mixed in the gas when you dont pull the clutch after a dyno run and the dyno keeps spinning the engine its not getting any oil notice it locked up when the dyno was spinning the engine.
I’m just curious ,, Did you have any 2stroke oil in the gas? It ain’t smoking any at all and even if you didn’t have any oil mixed in it,, it should have smoked from the oil deposits built up in the pipe . Next time don’t grab your push mower gas🤦♂️
No, i will never take my bike to him again. There is cooling hoses at the front, but they are not visible. The problem was not that the bike got too hot during the dynorun itself. The engine seized two times more during the winter iceracing season. Even that pipe i use is designed for tuned engines it was not really capable of letting the exhaust gases out. The stinger section was too narrow causing too high exhaust temp on the icetracks long straights.It's been taken care of now.
Dat engine break after hitting gas made the piston and cylinder cut,couse when he lets of the throttle gasoline and oil mix only comes from the idle nozzle witch gives a lot smaller mount of oil and gasoline mix than the headnozzle. And he had so high rpm that the engine did not get enough oil.. SORRY FOR BAD ENGLISH IM SWEDISH !
Oh Man, feel your pain fella. Spent some time at Shell R&D, best ever 2t oil we tested was Castrol A545 (now called Castrol Power1). But as previously mentioned, this was operator error. I was cringing after the first run when he just closed the throttle and let the "dyno run the engine" rpm down. Final comment, Dynojet kits are a waste of money. If you're spending money on dyno time, just buy a selection of main and pilot jets. That way you'll have them for future projects too.
ummm the secret is in the jet needles, no amount of jet swapping will get the same effect of a beautiful taper as opposed to the telephone poles US bikes come with.
i used to ride a cr 500 to work in antigua! i thought everyone knew that on 2 stroke at high revs when u cut the throttle u either hit the kill switch or pull in the clutch. i prefer hit the kill switch as the fuel with no ignition cools the cylinder.
The bike has been running with this jetting for two years without any problems, so it,s not lean at the pilot. it,s been dynoe'd before with the same jetting.
letting it engine brake like that from top speed will kill it. your running it at high speed with minimal lubrication. many people do this to snowmobiles after pulling long lake runs and then coasting.
I'm not lyng I cleaned out my 1984 Yamaha DT 200R 2 stroke's rad coolant & i did mess up I should of put the coolant in the rad but :/ I put it in the over flow by accident! I ended up riding up my road (not even 1 Kilo) I saw my temp gauge reading HOT! yes the DT 200R's have temp gauge's. I went down a short trail as well then that's when i saw it on the red temp mark!! SO i shut it off but i actaully rode it slow not fast & I lucky didn't seize it up or break a piston ring or anything else. So I shut it off walk it home half way down my road I kicked it once it still fired up first kick haha gotta love the Japan Yamaha's. So what did i do next let it completely cool down & I called my local Dirt bike shop & I asked him that my yamaha's temp gauge is on the red mark. & he told me how to fix it so i drained my fluid :) I put it it the rad :D P. S. I did end up months after that same year (2013 fall) Blow the top end piston Hey that bike lasted a long 29 years It was a FUN! Fast! Enduro :D it could top out at 140 kph at 7500 RPM! in 6th gear! & in 5th gear @ 120 kph @ 8100 RPM wide Open YA! Wow! could that bike climb up hills!
When you let go of the throttle on a 2 stroke it will get no oil st high rpms but mid rpms when u let go it doesn't matter because the pilot jet gives it fuel because of the vacuum
Honestly Yes I didn't know where to put the coolant. I do now! Peace happy Trails or flying on your Yz's Cr's Rm's & Kx's & Cam am mx1's & KTM's & lol husky 500cc Big bore's haha etc etc. Cheers
Keep in mind, the 500cc two strokes had really low compression ratios...around 7:1 depending on the year. These bikes were detuned from the mighty 1985 CR500R so that people could ride them. Of course a 125 two stroke will have more horsepower per liter with higher compression, power-valves, etc.
Like Paul Mauser said, the CR500 is down on max hp because the powerband is actually ALL midrange and not on top end. It might make only 10-15 maximum horsepower over a 250cc 2 stroke, BUT it probably makes about 50hp at 7000rpm! Compare that to a KTM 125cc 2 stroke that makes 40hp, but it makes that hp only at high rpm... At 7000rpm, the KTM 125cc probably makes 15hp, then makes 40hp at 12,000+ rpm. Also a CR500's torque would be un-godly.. Its not a max hp bike, if it make 90hp who could ride it???
Om den den där knickedicken hade dragit in kopplingen efter varje pull och använt bromsen i bänken så hade det gått bra. Märkligt är det att han tar åt sig bromsningar när han inte vet hur man gör.
Min teori på varför den skar i slutet av dagen är att ni motorbromsat hela dagen med en motor som bara har smörjning när ni gasar. Känns som den uppenbara förklaringen tycker jag när det är en 2-taktare vi pratar om. Rätt eller fel? Kanonfin hoj i övrigt så det var tråkigt att den gick sönder!
+Erik Blomdahl Helt rätt! 99% säker på att de va de som gjorde att den skärde, När man slutar gasar så stänger man throtteln i föggen, De gör så att den knappt får någon luft och bensin, Och med tanke på att de e tvåtakts oljan i bensinen som smörjer den. De dem gör är att låta den gå på 8000rpm utan smörjning. Dem borde skaffa 4t istället..
You folks do know that the 2 stroke oil has little to do with lubricating the cylinder walls right? Your mixture meets the crank case first (bathing your crank), then the remaining fuel is atomized and pulled into the combustion chamber... Heat is likely the culprit here. Yes, engine braking (especially from high RPM WOT, to Zero throttle) can be detrimental because of lubrication starving the engine. Also too rich of a mixture can be just as harmful as too lean. A pin hole in the crank case is known to do this as well (allowing extra air in to the mixture).
The reason for the seizing was heat and nothing else. So you mean that the oil isn't important for lubricate the bore and piston rings? I don't understand what you mean when you first say that heat isn't the reason for the seizing, and then you say that engine braking is because of starving the engine..if you had seen the piston you would probably change your mind.
+rungassamydonovan47 what actually happens is the piston overheats and expands beyond normal engineered limits. This causes insufficient clearance between the piston and cylinder wall. more heat is generated as a result which melts things together. Piston overheating can be caused by a number of things. Common causes include lean air fuel mixture, not enough oil in fuel, worn piston rings, incorrect ignition timing. The truth is rings have a hard life in a two stroke because of the lubrication setup and fact they slide over voids ( the ports). They are extremely important because blow-by effects the incoming mixture charge in the crankcase. Crank sealing and crankcase sealing is extremely important on a 2 stroke.
THAT is why you dont coast for long periods of time on two strokes. By fuel starving the engine, you end up ceasing the flow of lubrication, the premix...
Dude needs a manual brake on the dyno drum, or to slightly drop the rpm and clutch out of it at the end of the pull. Dyno guy wrecked that piston no questions! You can't turn a motor 8000 then slap the carb closed so there is no lube and expect the piston to not stick.
Hallå Darko! jag hade en annan pipa på när jag körde hos honom, och den pipan bygger för mycket värme kom vi på sen. Stingern är för trång. jag har bränt 3 kolvar i vinter, men nu är pipan ombyggd med större diameter. Jag har ett nytt roligt projekt på gång nu :=).
Manual brake would be nice to avoid unnecessary decel of the engine but will not help a too lean of pilot jet which is needed for street riding or racing. Not trying to defend him or anything as I personally would not have been chopping the throttle like that without pulling in the clutch or using a brake of some sort. Just be glad it happened on the dyno instead of on the street where the price would have been A LOT higher.
you should have pulled the clutch after the flat out section , 'cause when decelerating the carb is "closed" and there isnt enough oil to lubricate the piston.. ceers..
sounded lean as hell plus not one bit of smoke. i like to hear a 2 stroke load up alittle on the hit then clear up, that bike bogged do to lean condition. poor bike didnt stand a chance these guys tuning it.who cares how much power it makes on a glory run i want my junk to last lol
either crap oil, most likely that, or too hot, but before overheat would come, it should have dumped coolant. Always use at least 50% high octane leaded, it makes engines live, even though your stuck with yesteryears tech in the cr... It's a bike with simplicity but at a loss of HP across the board compared to a kx....
***** as far as I know gas rated at 100 octane is unleaded. While I do agree that the pipe is important, so is timing, lubrication and induction. In the real word the cr holds nothing over the kx even you should know that
***** The kx is meant to be a high speed monster, not only motor but handing. The cr is suited to tight tracks. and it's all in the rake. The cr should have absolutely no advantage on the bottom where the power valves do their magic. Don't get me wrong, I love big bore 2 strokes and wouldn't pass on a cr if the price was right. So let's agree that the big bore 2 stroke beasts are a ton of fun, can't get 'em anymore....
Remind me never to take my bike to this guy... Has it ever crossed your mind the bike seized due to the fact the running temps were to high? Again due to the fact theres no FAN INFRONT OF THE RAD... Bike has got to hot & seized... :/
Something tells me the fuel/oil mix was a little lean on the oil side in the hunt for 60whp!! You guys had 59whp, thats obviously about 65+ hp on the engine, thats good enough! Also I agree with the non-clutching theory, the engine is seeing a/f mix anytime its running but it is seeing a MUCH smaller ammount of fuel with the throttle closed and at top rpm. That realllllllly sucks that the dyno guy cost you a top end. But hey, you live and you learn and this video will save me from doing the same thing and thats all that matters :) haha.
The dyno guy didn't know what he was doing, not because he didn't clutch in, but because he didn't use an AFR meter. The piston seized because it lacked fuel and was too much air, making it so hot that it melted.
This guy should not be allowed to dyno a two strokes !!!! He did exactly what you MUST avoid on a dyno , and as soon as you are on a good jetting set up , your are pretty sure to seize it when braking with throttle closed without clutching The operator should pay the engine rebuild !! Stinger size is another problem , whatever the stinger , this guys would seize all two strokes well jetted engine ....
Billy Woods There are all kinds of timing adjustments on a two stroke, Ignition timing - Changed by moving the stator plate - Determines when the spark plug fires in relation to stroke. Intake and Exhaust Timing - Changes by porting, you can raise or lower the ports. Can alter compression, determines overlap, when fuel can enter and for how long. . .just like changing camshafts in a four stroke. . .think valve timing and overlap.
+pavel1809 letting the piston coast when he lets off the gas. when ur not on the gas it doesn't lube the piston so when he let off it seized the piston. your expose to pull in the clutch when u let off.
ok so when u hit the gas it lubes the motor with the oil and gas, so when he lets off the gas the tires still spins but hes no on the gas. so the motor is dry. when u let off the gas and pull the clutch the engine dis engages so the piston stops.....it doesn't run dry. he didn't pull in the clutch so the tires still moving forcing the piston up and down with no gas. there for it ran dry and seized
WAS treibt IHR da in dem VIDEO ? 1: Man stellt den MOTOR daheim ein ;-) , perfekter zündpunkt , Vergaser etc .....dann Leistung prüfen , ob über 68ps oder an die 75PS oder mehr ; 2TAKTER poliert man im INNERN und optimiert die Strömungswege , desweiteren POLIERT man das KURBELGEHÄUSE , weil auch dort das GEMISCH fließt . Original Cr500 innen poliert , Ich schätze locker 75PS !°! UND 100% WETTBEWERBSfähig in der Weltmeisterschaft, unter den Top10 , wenn der Fahrer gut ist .! 2: Ein 2takter muß immer ZWISCHENGAS haben ! DU kannst nicht BERG AB rollen und das GAS zu lassen , weil dann der KOLBEN frißt , weil er ungeschmiert ist ! 3: Im Stand solche Drehzahlen immer wieder zu fahren , geht nicht ohne VENTILATOR von vorne , damit die Motorkühlung einigermaßen funktionieren kann . 4: Gut das der Motor nun durch ist , weil aus FEHLERN lernt man ! Ich habe Dir ein paar Dinge geschrieben , ums nächstes MAL besser zu machen . 5: ein innen polierter motor , hängt am GAS , immer ! Es ist so , wie es ab WERK eigentlich gehört hätte , aber aus Kostengründen nicht praktiziert wird ! Du mußt Dich also Selber bemühen , Motor komplett zerlegen , polieren , überarbeiten , neu dichten und SPA? haben mit einen ECHTEN RENNMOTOR ! Wettbewerbsfähig , weil Du an den SPEZIFIKATIONEN ORIGINAL bleibst , aber gut 10PS mehr hast , was bei einen Bike mit circa 100kg , eine NEUE WELT ist ! 6: die 58ps auf dem Leistungsprüfstand besagen nur , das DU 10PS unter der WERKSSTREUUNG von Motoren liegst ( Verschleiß ) . 68PS haben sie mindestens , es können mehr Ps sein , wenn Du einen guten erwischt , ansonsten sind es mindestens 68PS . poliert sind es , wie erwähnt , gefühlte 75Ps oder mehr . Ps = horse power , in deutsch "PFERDE STÄRKEN" .
I cringed every time he let go of that throttle...
Dyno guy is a Newbie with 2 strokes. You can't let off the throttle on a 2 stroke and just roll. This is when the motor runs dry without oil
My yamaha DT125r had lubrication via oil pump and i changed it to oil/gas mixture because the plastic gear always broakes and then my bike gets dry. A huge problem on any yamaha DT
In reality the video name should be "How to easily seize CR500"
The exhaust bridge gets a lot of heat and tends to expand into the cylinder and touch the piston when under load and rpm which is the same area that got damage on yours, the bridge on my 500 has been sanded back a bit to allow for expansion, it will rev as high and as long as I want and no troubles with the engine, same piston for five years, just an idea
helo groutaone, i picked up a 1998 kx500 last weekend and i love it. its a monster lol
groutaone
sam cwach Nice bike, yep monster indeed, should provide an entertaining ride
Exhaust bridge probs reminds me of the SC500 Yamahas my two friends had - seemingly having the same problem. We tried drilling a small hole in the piston skirt inline with the bridge to keep the bridge cooler. I think we got the idea off either my TM400 or RM370, but it's been too long a time to recall exactly
+ViperACR01 i had an 1983 cr250 with an exhaust bridge, Wiseco's instruction sheet said to drill a small hole (can,t remember the size, or if they said one or two holes, or the location ), we didn't have any issues afterward. I bought the bike with an exhaust side meltdown.
I had a 1978 Penton 250 that was the first bike I ran across with a piston hole for the exhaust bridge. Was freshening the top end for an up coming weekend enduro and if i recall they wanted a .040 hole in the exhaust skirt for the bridge. Unfortunately I made a mistake and drilled it on the intake side (crap!!). Enduro this week end and another piston a week away....went ahead and put it together...I mean a .040 hole in the intake skirt couldn't make that much difference, right? WRONG WRONG WRONG!! Turned a 40 horse mudslingin rooster into a slug that wouldn't pull a sick whore off a tricycle.
You're supposed to clutch it after wailing on the throttle.
Exactly.
but than thats allowing very little oil from the gas into the engine, increasing the wear
No when you let your throttle go you cilinder gets pretty mutch no oil at all and when you leave it in gear your cilinder will stay at high rpm's with low fuel & oil and when you clutch it it ill drop at rpms reely quickly to stationary so it gets all that it needs so to say
Jon Lesensky You couldn't be more wrong.
Actually , him wailing the throttle and leaving the tire to spin while he completely shuts off the throttle is not very good for your 2 stroke. The tire has the momentum from the full throttle dyno pull most likely 5th gear lol. And to just shut off the throttle slide with all that momentum you will be winding the shit out of your motor. (pretty much engine braking on a 2 stroke) Yea, definitely could of been prevented just by pulling in clutch to shut the back wheel momentum off from the crank. Lol, i'm 15 and i know this come on. Also it looks like hes running like 50:1 premix with little to no smoke. if your trail riding thats perfect but not for dyno runs; lack of oil was for sure his problem.
please inform me on how i "couldn't be more wrong." LOL
You should probably stick to R/C cars lol.
loving the engine breaking and the absence of a cold air fan
Its a simple reason for seizing, any rider should know if you take any two stroke to high rpm and then chop the throttle without clutching all the fuel/oil that lubricates the motor is taken away but because the clutch is still enguaged and its in gear the need for fuel/oil remains the same but closing the throttle cuts the supply creating a super lean air/fuel condition causing it to seize. Had he pulled the clutch in when the throttle was chopped would prevent it, same can happen on huge sand dunes when people haul ass downhill and chop the throttle, cause its still in gear forcing high rpms but no fuel/oil can get in to cool and lube things. Only happens on two strokes that need fuel/oil for lubrication.
I was tought to always blip the throttle to keep her lubed especially after long wide open straights etc
Here is a pro tip. After a long, high RPM run with a two stroke, push the kill switch while holding the throttle wide open for a few seconds, cools the cylinder and piston down. Thats an old pro desert racing trick.
works like a charm
yes or hit the choke if the terain allows
Ive never heard this before, that's really a legit trick? what does holding the throttle wide open while killing the motor for a few sec do? Im super curious about this now.... And Thanks for the tip!
It lets the fuel/oil/air mixture continue to flow into the motor without being burnt off, so it cools and lubes the piston and cylinder, preventing this exact thing from happening.
I have a friend who used to have a handlebar choke cable. He'd give a shot of choke at the end of long straights to cool things down before heading back into the bush.
notice there's no fan to cool the engine. no throttle blips to give the engine lubrication. Pretty stupid.
yeah lets just engine brake the fuck outta this 2 stroke and see what happens.
I would have screamed at them in rage after seeing how they handle a 2 stroke at this dyno.
its a two stroke engine. It is not lubricating itself while off throttle and at this revs god i can only imagine how dry it must have been inside... lol
+Adasiek9595 It's sad to witness such a machine being slowly destroyed on the inside lol
Yes, Eric Elder, stinger section. Do you know which part of the expansion chamber that is? Do you understand how that affects the character of a twostroke engine and the powerband together with exhaust temp?
Two stroke only get lubrication when fuel get in while reving it letting the engine stop it without some braaps doesn’t lubricate it which seizes it
Aldrig motorbromsa 2takt särskillt utan separat smörj :( hur vass blev den efter borrning osv? :)
Cykelen sitter fast med framhjulet så helly felly, man ska ha en broms på rullen. Bromsar du med bakbromsen så glöder skivan innan rullen stannar. Motorbrom på 2-takt är samma sak som ingen oljetryck på 4-takt, Jag körde den här cykelen i min bänk med 2 olika pipor och det hände inget.
I hope they paid for the repairs.
Sadly most dyno shops never do. They usually have the owner of the vehicle sign a waver that makes it so they have no responsibility for engine damage. Atleast here in the states every dyno has you sign papers and if you're not willing to they will not tune your car or bike.
in that case i would be willing to ""drive"" the bike
WRider Thats another thing... alot of them claim only a certified technician for the companies Dyno is allowed to use vehicles on it. I've tried to say the same thing where i asked if i could just drive my vehicle on the dyno. and they claim that if youre not trained in the field of driving on a dyno you can destroy it. Its sort of a lose lose with tunning .. I mean yeah they can squeeze some more power out. But at the end of the day they make you pay ridiculous prices and if they blow your motor its on you.
When you let a bike come down from that rpm with no gas entering it there is also no oil lubricating it either. General 2 stroke knowledge!
+David Neumann thats why the piston seized and the cylinder was scratched
No cooling fan?
Lean oil to fuel ratio?
Ive run my CR500 for years on 100 octane gas at 40:1 with Klotz castor, engine brake, and have never had any engine problems whatsoever on any of my bikes, for that matter. Bore & hone that cylinder out to the next oversize, chamfer the port windows and get a freshly forged Wiseco in there, mix up some good stuff at 40:1 and go at it with a cooling fan (or 2) blowing through those radiators. You might want to check out your pipe & stinger dimensions too..
Why is there no smoke, someone forget the oil ?
Why don't they just pull the clutch after they close the throttle? A 2 stroke doesn't get enough fuel/oil mix when letting off the throttle
I thought you were supposed to use a dial indicator or piston stop when you set the timing and not just "eyeball it" And was the carb loose or was he rejetting it cause that would def make it run lean along with just chopping the throttle at wot
2 strokes need blipping the throttle with the clutch pulled in right after highly loaded runs so that some lubrication could be ensured.
Every time the guy turns the throttle from full to zero my hearth skips a beat.
It seized because he shut the throttle and let it overrun with no fuel being fed into the engine. It runs on premix so the engine only gets lubricated if the throttle is open. In the old days, loads of bikes would seize at the end of the 1.5 mile start straight at Weston Supermare beach race. ...They would go flat out in top, shut off, seize.....go home....Thats why 4 strokes are better for high speed deceleration.
that cylinder was HUGE at the end!! WOW!
Suprised they expected it to not lock up. All the oil a 2 stroke gets is mixed in the gas when you dont pull the clutch after a dyno run and the dyno keeps spinning the engine its not getting any oil notice it locked up when the dyno was spinning the engine.
I’m just curious ,, Did you have any 2stroke oil in the gas? It ain’t smoking any at all and even if you didn’t have any oil mixed in it,, it should have smoked from the oil deposits built up in the pipe . Next time don’t grab your push mower gas🤦♂️
No, i will never take my bike to him again. There is cooling hoses at the front, but they are not visible. The problem was not that the bike got too hot during the dynorun itself. The engine seized two times more during the winter iceracing season. Even that pipe i use is designed for tuned engines it was not really capable of letting the exhaust gases out. The stinger section was too narrow causing too high exhaust temp on the icetracks long straights.It's been taken care of now.
what mix were they running that on? not one bit of smoke. dry as a bone
That guy belongs on a moped,I used to scream my cr500 to the moon,on a regular basis and this guy is actually putting along.
why are there bags on the handlebars ?
Dat engine break after hitting gas made the piston and cylinder cut,couse when he lets of the throttle gasoline and oil mix only comes from the idle nozzle witch gives a lot smaller mount of oil and gasoline mix than the headnozzle. And he had so high rpm that the engine did not get enough oil.. SORRY FOR BAD ENGLISH IM SWEDISH !
This YT video:
10 Of The Most Powerful Two Stroke Bikes.
Shows at 6m.03s just how a 2-stroke should be dyno tested on the shut-off.
2 strokes don't get enough oil if you close the throttle without pulling the clutch in
Oh Man, feel your pain fella. Spent some time at Shell R&D, best ever 2t oil we tested was Castrol A545 (now called Castrol Power1). But as previously mentioned, this was operator error. I was cringing after the first run when he just closed the throttle and let the "dyno run the engine" rpm down. Final comment, Dynojet kits are a waste of money. If you're spending money on dyno time, just buy a selection of main and pilot jets. That way you'll have them for future projects too.
Not to mention the weird to me numbering system Dynojet uses. What do you think of Dynojet needles?
ummm the secret is in the jet needles, no amount of jet swapping will get the same effect of a beautiful taper as opposed to the telephone poles US bikes come with.
So 59lb torque average so what bhp is it and is bike standard?
not much smoke coming outta that either...
dont they run the oil mixture way lower to prevent the oil from lowering the octane rating or something? like 50 or 60 to 1
Fuel wasn't the problem. Stinger dimension was.
@@lindseyhunt1090garageb i let my 80cc derbi run 35:1😂 let alone a 500cc 2stroke
i used to ride a cr 500 to work in antigua! i thought everyone knew that on 2 stroke at high revs when u cut the throttle u either hit the kill switch or pull in the clutch. i prefer hit the kill switch as the fuel with no ignition cools the cylinder.
The bike has been running with this jetting for two years without any problems, so it,s not lean at the pilot. it,s been dynoe'd before with the same jetting.
letting it engine brake like that from top speed will kill it. your running it at high speed with minimal lubrication. many people do this to snowmobiles after pulling long lake runs and then coasting.
I always feather the throttle on my 2 stroke when I max the speed out. Even when you're slowing down.
I'm not lyng I cleaned out my 1984 Yamaha DT 200R 2 stroke's rad coolant
& i did mess up I should of put the coolant in the rad but :/ I put
it in the over flow by accident! I ended up riding up my road (not even
1 Kilo) I saw my temp gauge reading HOT! yes the DT 200R's have temp
gauge's. I went down a short trail as well then that's when i saw it on
the red temp mark!! SO i shut it off but i actaully rode it slow not
fast & I lucky didn't seize it up or break a piston ring or anything
else. So I shut it off walk it home half way down my road I kicked it
once it still fired up first kick haha gotta love the Japan Yamaha's. So
what did i do next let it completely cool down & I called my local
Dirt bike shop & I asked him that my yamaha's temp gauge is on the red mark. & he told me how to fix it so i drained my fluid :) I put it it the rad :D P. S. I did end up months after that same year (2013 fall) Blow the top end piston Hey that bike lasted a long 29 years It was a FUN! Fast! Enduro :D it could top out at 140 kph at 7500 RPM! in 6th gear! & in 5th gear @ 120 kph @ 8100 RPM wide Open YA! Wow! could that bike climb up hills!
When you let go of the throttle on a 2 stroke it will get no oil st high rpms but mid rpms when u let go it doesn't matter because the pilot jet gives it fuel because of the vacuum
what gas tank and shroud are you using??
I diddnt see any blue smoke out of that exhaust... Got some good engineering here!
I’m surprised the piston lasted that long
Honestly Yes I didn't know where to put the coolant. I do now! Peace happy Trails or flying on your Yz's Cr's Rm's & Kx's & Cam am mx1's & KTM's & lol husky 500cc Big bore's haha etc etc. Cheers
Just want to know, what 2-stroke oil were you using? And your ratio?
About engine braking a 2 Stroke. This guy Toby Opferman explains it very well in this video (at 23:53)th-cam.com/video/2D_XxTFrq4M/w-d-xo.html
60 hp is pretty weak for a 500cc bike, just look at a ktm 125 exc, I've seen those dyno at around 40 hp..
KTM125EXC - 11 hp @ 7500 rpm and 15 or so ft lb of torque? I bet you never even rode a 125.
BurningTirez
that's not right a 1998 cr 80 make's 20+ hp!
Keep in mind, the 500cc two strokes had really low compression ratios...around 7:1 depending on the year. These bikes were detuned from the mighty 1985 CR500R so that people could ride them. Of course a 125 two stroke will have more horsepower per liter with higher compression, power-valves, etc.
250's make over 40, the ktm 125 is brand new and barely making 33. Keep in mind though that a 500 actually has a low end.
Like Paul Mauser said, the CR500 is down on max hp because the powerband is actually ALL midrange and not on top end. It might make only 10-15 maximum horsepower over a 250cc 2 stroke, BUT it probably makes about 50hp at 7000rpm! Compare that to a KTM 125cc 2 stroke that makes 40hp, but it makes that hp only at high rpm... At 7000rpm, the KTM 125cc probably makes 15hp, then makes 40hp at 12,000+ rpm. Also a CR500's torque would be un-godly.. Its not a max hp bike, if it make 90hp who could ride it???
Wisco had me drill a small hole common to the exhaust port bridge bellow the rings. Guess they know a thing or two.
Om den den där knickedicken hade dragit in kopplingen efter varje pull och använt bromsen i bänken så hade det gått bra. Märkligt är det att han tar åt sig bromsningar när han inte vet hur man gör.
Min teori på varför den skar i slutet av dagen är att ni motorbromsat hela dagen med en motor som bara har smörjning när ni gasar. Känns som den uppenbara förklaringen tycker jag när det är en 2-taktare vi pratar om.
Rätt eller fel?
Kanonfin hoj i övrigt så det var tråkigt att den gick sönder!
+Erik Blomdahl Helt rätt! 99% säker på att de va de som gjorde att den skärde, När man slutar gasar så stänger man throtteln i föggen, De gör så att den knappt får någon luft och bensin, Och med tanke på att de e tvåtakts oljan i bensinen som smörjer den. De dem gör är att låta den gå på 8000rpm utan smörjning. Dem borde skaffa 4t istället..
no wonder it seized lmao. No gas, no oil.
You folks do know that the 2 stroke oil has little to do with lubricating the cylinder walls right? Your mixture meets the crank case first (bathing your crank), then the remaining fuel is atomized and pulled into the combustion chamber... Heat is likely the culprit here. Yes, engine braking (especially from high RPM WOT, to Zero throttle) can be detrimental because of lubrication starving the engine. Also too rich of a mixture can be just as harmful as too lean. A pin hole in the crank case is known to do this as well (allowing extra air in to the mixture).
The reason for the seizing was heat and nothing else. So you mean that the oil isn't important for lubricate the bore and piston rings? I don't understand what you mean when you first say that heat isn't the reason for the seizing, and then you say that engine braking is because of starving the engine..if you had seen the piston you would probably change your mind.
its not pulled, its pushed up through the transfers and up the walls.
Question:Why 2 stroke engine usually seize?
+rungassamydonovan47 what actually happens is the piston overheats and expands beyond normal engineered limits. This causes insufficient clearance between the piston and cylinder wall. more heat is generated as a result which melts things together. Piston overheating can be caused by a number of things. Common causes include lean air fuel mixture, not enough oil in fuel, worn piston rings, incorrect ignition timing. The truth is rings have a hard life in a two stroke because of the lubrication setup and fact they slide over voids ( the ports). They are extremely important because blow-by effects the incoming mixture charge in the crankcase. Crank sealing and crankcase sealing is extremely important on a 2 stroke.
THAT is why you dont coast for long periods of time on two strokes. By fuel starving the engine, you end up ceasing the flow of lubrication, the premix...
You can hear its about to go bad just before the last run :)
Dude needs a manual brake on the dyno drum, or to slightly drop the rpm and clutch out of it at the end of the pull. Dyno guy wrecked that piston no questions! You can't turn a motor 8000 then slap the carb closed so there is no lube and expect the piston to not stick.
Hallå Darko! jag hade en annan pipa på när jag körde hos honom, och den pipan bygger för mycket värme kom vi på sen. Stingern är för trång. jag har bränt 3 kolvar i vinter, men nu är pipan ombyggd med större diameter. Jag har ett nytt roligt projekt på gång nu :=).
The look and your faces at 4:32
PRICELESS LETTY
Game over, player 1 ! ;-)
Manual brake would be nice to avoid unnecessary decel of the engine but will not help a too lean of pilot jet which is needed for street riding or racing. Not trying to defend him or anything as I personally would not have been chopping the throttle like that without pulling in the clutch or using a brake of some sort. Just be glad it happened on the dyno instead of on the street where the price would have been A LOT higher.
you should have pulled the clutch after the flat out section , 'cause when decelerating the carb is "closed" and there isnt enough oil to lubricate the piston.. ceers..
I use 32:1 ratio but add a littlebit more oil too it. This is why.
60hp? Thats the same as my 450 4 stroke?
sounded lean as hell plus not one bit of smoke. i like to hear a 2 stroke load up alittle on the hit then clear up, that bike bogged do to lean condition. poor bike didnt stand a chance these guys tuning it.who cares how much power it makes on a glory run i want my junk to last lol
Shame the dyno op killed by letting the drum spin it down.
it needs oil....good oil!
and a lot of cooling
when its on 7000rpm and throttle closed 😂
very stupid guys.
you have to listen to 2stroke
2stroke lives
Why you don’t engine brake
either crap oil, most likely that, or too hot, but before overheat would come, it should have dumped coolant. Always use at least 50% high octane leaded, it makes engines live, even though your stuck with yesteryears tech in the cr... It's a bike with simplicity but at a loss of HP across the board compared to a kx....
*****
as far as I know gas rated at 100 octane is unleaded. While I do agree that the pipe is important, so is timing, lubrication and induction. In the real word the cr holds nothing over the kx even you should know that
*****
The kx is meant to be a high speed monster, not only motor but handing. The cr is suited to tight tracks. and it's all in the rake. The cr should have absolutely no advantage on the bottom where the power valves do their magic. Don't get me wrong, I love big bore 2 strokes and wouldn't pass on a cr if the price was right. So let's agree that the big bore 2 stroke beasts are a ton of fun, can't get 'em anymore....
Remind me never to take my bike to this guy... Has it ever crossed your mind the bike seized due to the fact the running temps were to high? Again due to the fact theres no FAN INFRONT OF THE RAD... Bike has got to hot & seized... :/
Something tells me the fuel/oil mix was a little lean on the oil side in the hunt for 60whp!! You guys had 59whp, thats obviously about 65+ hp on the engine, thats good enough! Also I agree with the non-clutching theory, the engine is seeing a/f mix anytime its running but it is seeing a MUCH smaller ammount of fuel with the throttle closed and at top rpm. That realllllllly sucks that the dyno guy cost you a top end. But hey, you live and you learn and this video will save me from doing the same thing and thats all that matters :) haha.
The dyno guy didn't know what he was doing, not because he didn't clutch in, but because he didn't use an AFR meter. The piston seized because it lacked fuel and was too much air, making it so hot that it melted.
It has nothing to do with fuel supply. I have explained the problem with stinger pipe diameter several times so sorry guys, it was not that simple😉.
Christ no fan blowing in radiator... Surprised it didn't melt earlier!!
So what was the hp ?
can if you hit kill switch at same time
This guy should not be allowed to dyno a two strokes !!!!
He did exactly what you MUST avoid on a dyno , and as soon as you are on a good jetting set up , your are pretty sure to seize it when braking with throttle closed without clutching
The operator should pay the engine rebuild !!
Stinger size is another problem , whatever the stinger , this guys would seize all two strokes well jetted engine ....
how to make engine not last
Incrivel como vocês conseguiram quebrar uma CR500,
with power?
i would of put a large fan in front of the rads to cool off the engine , might of got more horsepower
Advanced the timing and lunched it.
timing? its a 2 stroke 500 bud, no timing here
Billy Woods Ignition timing, bud!
Billy Woods Changing the timing on a 2 stroke = moving the stator plate
Billy Woods
There are all kinds of timing adjustments on a two stroke,
Ignition timing - Changed by moving the stator plate - Determines when the spark plug fires in relation to stroke.
Intake and Exhaust Timing - Changes by porting, you can raise or lower the ports. Can alter compression, determines overlap, when fuel can enter and for how long. . .just like changing camshafts in a four stroke. . .think valve timing and overlap.
Billy Woods HAHAHHHA chirps a guy and has no clue
A stock 500 has 60 hp.
*bruh did he even hit the power band*
I had a feeling that bike was running to lean from the first pull.
Don Rossco Joe
You the man!!
A tuners ear!!
what cause to the piston to seized ??
+pavel1809 letting the piston coast when he lets off the gas. when ur not on the gas it doesn't lube the piston so when he let off it seized the piston. your expose to pull in the clutch when u let off.
i still don't get it ??? lol
ok so when u hit the gas it lubes the motor with the oil and gas, so when he lets off the gas the tires still spins but hes no on the gas. so the motor is dry. when u let off the gas and pull the clutch the engine dis engages so the piston stops.....it doesn't run dry. he didn't pull in the clutch so the tires still moving forcing the piston up and down with no gas. there for it ran dry and seized
ok i think I get it
Really good..... but have no idea how to run a two-stroke engine...
behövs inte Johnny, varför hände inget sånt när du var hos mig och vi körde fler pull och det var kallare.
one does not simply let go of the gas on a 2-stroke
Sweet Lord, Jesus and Mary!!!
WAS treibt IHR da in dem VIDEO ? 1: Man stellt den MOTOR daheim ein ;-) , perfekter zündpunkt , Vergaser etc .....dann Leistung prüfen , ob über 68ps oder an die 75PS oder mehr ; 2TAKTER poliert man im INNERN und optimiert die Strömungswege , desweiteren POLIERT man das KURBELGEHÄUSE , weil auch dort das GEMISCH fließt . Original Cr500 innen poliert , Ich schätze locker 75PS !°! UND 100% WETTBEWERBSfähig in der Weltmeisterschaft, unter den Top10 , wenn der Fahrer gut ist .!
2: Ein 2takter muß immer ZWISCHENGAS haben ! DU kannst nicht BERG AB rollen und das GAS zu lassen , weil dann der KOLBEN frißt , weil er ungeschmiert ist !
3: Im Stand solche Drehzahlen immer wieder zu fahren , geht nicht ohne VENTILATOR von vorne , damit die Motorkühlung einigermaßen funktionieren kann .
4: Gut das der Motor nun durch ist , weil aus FEHLERN lernt man ! Ich habe Dir ein paar Dinge geschrieben , ums nächstes MAL besser zu machen .
5: ein innen polierter motor , hängt am GAS , immer ! Es ist so , wie es ab WERK eigentlich gehört hätte , aber aus Kostengründen nicht praktiziert wird ! Du mußt Dich also Selber bemühen , Motor komplett zerlegen , polieren , überarbeiten , neu dichten und SPA? haben mit einen ECHTEN RENNMOTOR ! Wettbewerbsfähig , weil Du an den SPEZIFIKATIONEN ORIGINAL bleibst , aber gut 10PS mehr hast , was bei einen Bike mit circa 100kg , eine NEUE WELT ist !
6: die 58ps auf dem Leistungsprüfstand besagen nur , das DU 10PS unter der WERKSSTREUUNG von Motoren liegst ( Verschleiß ) . 68PS haben sie mindestens , es können mehr Ps sein , wenn Du einen guten erwischt , ansonsten sind es mindestens 68PS . poliert sind es , wie erwähnt , gefühlte 75Ps oder mehr .
Ps = horse power , in deutsch "PFERDE STÄRKEN" .
Zylinder kann man neu hohnen lassen , einen Kolben mit Übergröße . 200Euro kosten ! 100euro für Kolben , 100Euro fürs Hohnen
MEIN BEILEID übrigens und DANKE für`s TEILEN :-) . Es hat Dich Hart erwischt
no shit it seized the piston.. they overheated the piss out of it, no fan or air running on it. those things overheat just idling at a stand still.
Too lean?
R.I.P. Honda 😕
Det skulle säkert gått bättre med lite vind i fronten under bänkningen!
Den hojen är en av de fränaste nu. cr550
dudes I ran a wisco pro x in a kx 500 and never melted one
I feel like it seized very quick