this is the only video i could find that literally tells u everything u need to know, doing my first top end rebuild on my 250r. Thanks for the knowledge
Heck yeah brother! Glad it helped! Any other questions let me know. Post them here and that way anyone else will be able to see. Share share share! 😎 Thats all I ask. Bigger I get the better the content and can start give aways and contests and all that good stuff!
I'm ready to do mine (in a few days when all goodies arrive to my door) crf250 2009. It's the first time for me also. Good infos on your video, thanks.
Nice! Good deal. Glad it helped. Let me know if you have any questions. One thing I've been thinking about off and on is the next time I remove my cam I'm going to use a little carb cleaner and clean off the sides of the cam chain right where the timing marks are on the cam and then I'm not going to let the chain pop off the crank and that way I know exactly where to put the cam on the Chain when I reinstall it. You just have to make sure not to let the chain pop off the crank down by the flywheel.
You are a legend for sharing the vid. Unfortunately my 09 is due but I'm in Australia. The part cost is enough to scrap my bike instead of a rebuild. I don't have the tools required anyway. I'd be sending Off & labour costs don't help
Correct. Not with these 4 strokes. Just use a rubber rmallet and tap both ends to slowly work apart. I highly recommend the dry install method in a new piston ring kit and light cylinder hone.
Hey Andrew I’m about to install my new top end rebuild on my 2007 crf250r. I’m pretty new to this so your video was extremely helpful. However I’m nervous about my crankshaft, i feel like it’s kind of loose. What’s the clearance u used on urs to check if it was too loose or not? Also, when u adjust the crank on the right side of the engine to line up with the tick before putting ur cam on, does the flywheel tick on the other side of the engine also move at the same time as the other side crankshaft as ur adjusting it? Ik that probably sounds confusing
Sorry for the late response. Glad it's helping. Hoped I'm not too late to help. I didn't really check mine but I'm about to replace it and the manual states that there should only be side to side clearance of the connecting rod of about .020" and absolutely NO Up and DOWN movement. This is really all is states. I ended up getting a new OEM Crank, Bearings, Seals, Piston, Piston Pin, Timing Chain and chain guide. The Punch mark on the balancer shaft gear and the the line on the flywheel will move at the same time being they are both attached to one end of the crankshaft. When you bring the piston to top dead center on the compression stroke, the punch mark on the clutch side of the crank will align with the arrow on the outside, front edge of the access bore. The line on the right of the two marks on the flywheel will need to be precisely lined up with the notch on the inside of the threads of the flywheel timing access bore. Then you can line your cams timing gear lines up to be level with the top of the cylinder head. Make sure that you snug down the two cam retainer caps and let the chain tension push in on the chain to sure you still have correct alignment of the cam timing gear marks. Once you have everything lined up, cam chain on, cam caps snugged down and tension released to make chain tight, check the flywheel line again. Make it dead on with that notch in the threads and then check the cam gear. If it's off you'll know. It will be a good 3/16" offset from where it should be in either direction. If it is, just pop it over the teeth, one direction or the other that it needs to go.
You're either off a tooth on your computer timing or your idle screw is wrong. Try turning the idle screwnin al the way and backing it out 5-5.5 turns and see how it starts.
So with cam timing being off by one tooth bike will start and stall few times ? is also sign of cam timing beiing off that bike is hard to start even when its warmed up ?
i ride mine to and from work everyday wheelie and bounce off the rev limiter 4 shifts ina row then go home to ride it around more everysingleday think im pushing 300 hours jus keep adjusting valves it jus got very hard to start i think its time is coming lol
Daaaang Smookey!!!! 🤣 300hrs. You better do a rebuild before she throws a rod or something. Ha ha. I just checked my leak down on this too after 56.5hrs today and I went from 3psi loss to about 5.5-6psi loss via blow by. It was about 3% loss to now 5% loss. She ran great at the track today though. I've been using Motul 15w/50 5100 oil since spring and spring for so good. Loving it.
Great video! I’m new to the 4 stroke scene. Me and my son just took on a project. 2008 Crf250r we are doing a top end rebuild everything seemed to be going good until cam install. Cam has excessive side to side movement. Excessive to the point of decompression bolt head hitting head and cam lobe hitting rocker! Any help is appreciated. Thank you
Gotcha. Yeah there shouldn't be side to side play like that at all the bearing on the gear side does move but the bearing on the other side should stop it from moving one way or the other but one thing you have to make sure that you have are the locating rings that go on the bottom side of the Cam Bearing retainer caps you can see how the cam bearings have slots in them. There are supposed to be keeper rings that lock the bearings in place. So I would check and make sure that you aren't missing those. I do show those in my video and warned people to make sure that they don't drop down into the cam chain galley. Which well be accessible by taking the left side cover off after you drain the oil. Keep me posted what you find
@@Fixin2Ride-Official- thank you. That makes sense. The non gear side cam bearing is slip fit also. Clips are in place. The cam actually moves side to side like bearings are to big. This is so interesting lol
Definitely fun to learn about. If you have yourself a channel obviously then you should make a quick video and post a link. You can download the app to your phone make a quick video and then upload a real fast if you're connected to your home Wi-Fi. That way you can show me exactly what you're talkin about
Hey brother, my 05 seems to have lost a little compression, starts up for a little bit but then won’t idle, hard to start, and doesn’t respond to carb tuning. My valves are all in spec, could my piston need replacement? (Does your bike behave this way before it needs a top end?)
Yep. All classic signs. I'm going to rebuilding the entire engine now on this bike. I installed the top end at 26hrs and it's got around 86 now. I've been riding a lot harder but tell tale signs are less compression, especially when hot, easier kicking over and now I saw a little poof of blue smoke the other day when warming up. I did do a leak down test the other day and I was at 5-6psi loss via blow by. I was 3psi initially. It might be more now. Just placed an order for all oem stuff. $723 incl. tax. Shipped from rockymountainatvmc.com
@@Fixin2Ride-Official- thank you so much for the fast reply. I will be tearing into mine here shortly. I haven’t done this on this bike for 4 years haha I’m excited and scared
I got a full tear down video for a gasket it replacement on this engine when I first got it spring of 2020. Check it out. You got this though. Judt take your time and take pics and or keep bolts organized in baggies marked with sharpie
Hi. Is there any play on the crankshaft? In my 2015 CRF 250, I feel slight play along the sides and slightly up and down. Is this how it's supposed to be? 
A max of .030" is tolerable in thrust play (side to side) absolutely NO UP AND DOWN PLAY is allowed. If you have it, installed a new crank and crank bearings. Also would be a good idea to replace the baller shaft bearings if the crank has play and you replace the crank bearings.
@nr.1289 well then you might need new crank bearings if that's what you're talking about. You have connecting rod bearings on the big end of the crank as well as crankshaft bearings at either side of the crank
There should be a keeper on the bottom side of the crank behind the flywheel, and you should have a white-ish (often tan from the oil) chain slide on the front side of the chain galley that slips in and black one on the back side that is bolted in at the bottom and is pushed on by the cam chain tensioner on the back side of the cylinder.
@jadenwong27 OH good deal. You're good then. Just make sure you crank in the tensioner first before setting up the cam timing. I use a small screwdriver and a pair of vice grips
Thanks! I really try to do my best to be in depth with the repairs I do so there's no question on what people need to do on their own. I just really wish it would make the channel grow faster and bigger so I could do more things and provide more content.
@@Fixin2Ride-Official- thanks for the super quick reply. I am rebuilding the piston soon and I am pretty nervous. This video was a lot of help. I am most concerned about the timing marks. Last time I checked my valves I couldn’t find the tick mark on the flywheel towards the bottom of the engine. This is beginning to concern me after reading the other comments.
@jadenwong27 My pleasure! And ah. Yes, you have to make sure that the piston is TDCon the compression stroke. The punch marl on the crank gear on right side of engine will be lined up with the arrow on the case and the flywheel mark should be lined up with the notch in the threads. Use a flashlight and you'll have to get down below the hole to look up and see it. P.S. glad it's helping and don't worry, get it all together and double check stuff, kick it over slow at first to make sure it's all moving well. You'll be fine. And I'm here for any questions.
@jadenwong27 you bet. All I ask is that you share your favorite video and the channel in your social media accounts to help spread the word about the channel! Much appreciated!
Great question! That is the stock compression ratio piston. I first brought home a 13.5:1 but decided against it because I'm not sure how many hours are on this crank. And the increase compression is a little harder on the crankshafts. Since I've had the bike I've put at least a hundred hours on a crank and I don't know if it's ever been replaced. So when I replace the crankshaft I'll probably put a higher compression piston in it.
I’m so confused. The punch mark on the right side on my bike is not set up properly somehow. I rotated the crank to the mark and the exhaust rocker was still tight. Went to the next TDC (where the mark is not visible) and the rocker had play. I tried setting the cam timing so it was according to the punch mark and lightly began to kick the bike and felt valve interference so I stopped. When the punch mark is not visible and the bike is in TDC, the timing marks on the left side are aligned. Seems like someone didn’t know what they were doing during a bottom end rebuild, and I don’t know where to start.
If you're timing marks on the flywheel are not visible at the same time as the punch mark on the crank gear then chances are your flywheel key sheared. So you need to pull the flywheel and check the flywheel Woodruff key
You can tell if you're on the compression stroke by taking the plug out and putting your hand over the spark plug hole. Air will start rushing out on the compression stroke. If your bottom end is put together right you should see a punch mark on two gears and the flywheel on the other side of the engine should align with the notch on the inside of the threads for the view hole and the right of the two lines on the flywheel. And then your cam intake lobes should be facing mostly towards the back of the bike maybe up a little bit as well as both lines on the cam gear being parallel with the top of the cylinder head.
Okay so I just checked and you cant see the flywheel key slot in the crank from the end of the crank with the bolt off. The crank gears can only go on in one position. So its definitely your flywheel key being sheered. It will still be there when you look at the flywheel but the bottom half of the key is sheered off and still in the slot in the crank at a diff position. You'll need to get the flywheel puller from a shop or Rockymountainatvmc.com and get that flywheel off. You can order the flywheel key from Rockymountain as well in the "OEM" section.
this is the only video i could find that literally tells u everything u need to know, doing my first top end rebuild on my 250r. Thanks for the knowledge
Heck yeah brother! Glad it helped! Any other questions let me know. Post them here and that way anyone else will be able to see.
Share share share! 😎 Thats all I ask. Bigger I get the better the content and can start give aways and contests and all that good stuff!
@@Fixin2Ride-Official- Yeah if i get stumped on something ill come right back here thanks alot
Good deal!
@@tyler24533 how did it go?
I'm ready to do mine (in a few days when all goodies arrive to my door) crf250 2009.
It's the first time for me also. Good infos on your video, thanks.
Nice! Good deal. Glad it helped. Let me know if you have any questions. One thing I've been thinking about off and on is the next time I remove my cam I'm going to use a little carb cleaner and clean off the sides of the cam chain right where the timing marks are on the cam and then I'm not going to let the chain pop off the crank and that way I know exactly where to put the cam on the Chain when I reinstall it. You just have to make sure not to let the chain pop off the crank down by the flywheel.
You are a legend for sharing the vid. Unfortunately my 09 is due but I'm in Australia. The part cost is enough to scrap my bike instead of a rebuild. I don't have the tools required anyway. I'd be sending Off & labour costs don't help
Thank you. Sorry to hear. What part do you need? Piston kit?
Hey Andrew, would you reccomend doing a dry install on the piston? Also you didn't have to use a crankcase splitter at all correct?
Correct. Not with these 4 strokes. Just use a rubber rmallet and tap both ends to slowly work apart.
I highly recommend the dry install method in a new piston ring kit and light cylinder hone.
Hey Andrew I’m about to install my new top end rebuild on my 2007 crf250r. I’m pretty new to this so your video was extremely helpful.
However I’m nervous about my crankshaft, i feel like it’s kind of loose. What’s the clearance u used on urs to check if it was too loose or not?
Also, when u adjust the crank on the right side of the engine to line up with the tick before putting ur cam on, does the flywheel tick on the other side of the engine also move at the same time as the other side crankshaft as ur adjusting it?
Ik that probably sounds confusing
Sorry for the late response. Glad it's helping. Hoped I'm not too late to help. I didn't really check mine but I'm about to replace it and the manual states that there should only be side to side clearance of the connecting rod of about .020" and absolutely NO Up and DOWN movement. This is really all is states. I ended up getting a new OEM Crank, Bearings, Seals, Piston, Piston Pin, Timing Chain and chain guide.
The Punch mark on the balancer shaft gear and the the line on the flywheel will move at the same time being they are both attached to one end of the crankshaft. When you bring the piston to top dead center on the compression stroke, the punch mark on the clutch side of the crank will align with the arrow on the outside, front edge of the access bore. The line on the right of the two marks on the flywheel will need to be precisely lined up with the notch on the inside of the threads of the flywheel timing access bore. Then you can line your cams timing gear lines up to be level with the top of the cylinder head. Make sure that you snug down the two cam retainer caps and let the chain tension push in on the chain to sure you still have correct alignment of the cam timing gear marks.
Once you have everything lined up, cam chain on, cam caps snugged down and tension released to make chain tight, check the flywheel line again. Make it dead on with that notch in the threads and then check the cam gear. If it's off you'll know. It will be a good 3/16" offset from where it should be in either direction.
If it is, just pop it over the teeth, one direction or the other that it needs to go.
Gracias compa si nos sirvió el video mañana vemos si corre la chingadera esta 😮
In regards to what?
How long does it normally take to start after a rebuild. I couldn’t get mine to start after about 15 minutes
You're either off a tooth on your computer timing or your idle screw is wrong. Try turning the idle screwnin al the way and backing it out 5-5.5 turns and see how it starts.
So with cam timing being off by one tooth bike will start and stall few times ? is also sign of cam timing beiing off that bike is hard to start even when its warmed up ?
Yes it'll just be hard to start in general and the idol won't be very stable at a lower rpm.
i ride mine to and from work everyday wheelie and bounce off the rev limiter 4 shifts ina row then go home to ride it around more everysingleday think im pushing 300 hours jus keep adjusting valves it jus got very hard to start i think its time is coming lol
Daaaang Smookey!!!! 🤣 300hrs. You better do a rebuild before she throws a rod or something. Ha ha. I just checked my leak down on this too after 56.5hrs today and I went from 3psi loss to about 5.5-6psi loss via blow by. It was about 3% loss to now 5% loss. She ran great at the track today though.
I've been using Motul 15w/50 5100 oil since spring and spring for so good. Loving it.
Great video! I’m new to the 4 stroke scene. Me and my son just took on a project. 2008 Crf250r we are doing a top end rebuild everything seemed to be going good until cam install. Cam has excessive side to side movement. Excessive to the point of decompression bolt head hitting head and cam lobe hitting rocker! Any help is appreciated. Thank you
Gotcha. Yeah there shouldn't be side to side play like that at all the bearing on the gear side does move but the bearing on the other side should stop it from moving one way or the other but one thing you have to make sure that you have are the locating rings that go on the bottom side of the Cam Bearing retainer caps you can see how the cam bearings have slots in them. There are supposed to be keeper rings that lock the bearings in place. So I would check and make sure that you aren't missing those. I do show those in my video and warned people to make sure that they don't drop down into the cam chain galley. Which well be accessible by taking the left side cover off after you drain the oil. Keep me posted what you find
@@Fixin2Ride-Official- thank you. That makes sense. The non gear side cam bearing is slip fit also. Clips are in place. The cam actually moves side to side like bearings are to big. This is so interesting lol
Definitely fun to learn about. If you have yourself a channel obviously then you should make a quick video and post a link. You can download the app to your phone make a quick video and then upload a real fast if you're connected to your home Wi-Fi. That way you can show me exactly what you're talkin about
I knew that snap ring was gonna fall into the crank😂
Ya know. Lol. Its not a real engine rebuild if it doesnt. 🤣🤣🤣
Hey brother, my 05 seems to have lost a little compression, starts up for a little bit but then won’t idle, hard to start, and doesn’t respond to carb tuning. My valves are all in spec, could my piston need replacement? (Does your bike behave this way before it needs a top end?)
Yep. All classic signs. I'm going to rebuilding the entire engine now on this bike. I installed the top end at 26hrs and it's got around 86 now. I've been riding a lot harder but tell tale signs are less compression, especially when hot, easier kicking over and now I saw a little poof of blue smoke the other day when warming up.
I did do a leak down test the other day and I was at 5-6psi loss via blow by. I was 3psi initially. It might be more now. Just placed an order for all oem stuff. $723 incl. tax. Shipped from rockymountainatvmc.com
P.S. thanks for watching!
@@Fixin2Ride-Official- thank you so much for the fast reply. I will be tearing into mine here shortly. I haven’t done this on this bike for 4 years haha I’m excited and scared
I got a full tear down video for a gasket it replacement on this engine when I first got it spring of 2020. Check it out.
You got this though. Judt take your time and take pics and or keep bolts organized in baggies marked with sharpie
@@Fixin2Ride-Official- was that just a craftsman torque wrench? I have a cheapo one from harbor freight but I don’t trust it one bit haha
Hi. Is there any play on the crankshaft? In my 2015 CRF 250, I feel slight play along the sides and slightly up and down. Is this how it's supposed to be?

A max of .030" is tolerable in thrust play (side to side) absolutely NO UP AND DOWN PLAY is allowed. If you have it, installed a new crank and crank bearings. Also would be a good idea to replace the baller shaft bearings if the crank has play and you replace the crank bearings.
this is about the play in the shaft bearings. there is no play on the connecting rod. there is play on the shaft up and down and sideways
th-cam.com/video/R94-IBISx8k/w-d-xo.htmlsi=IgrlSNrbbmwn_JhN
@nr.1289 well then you might need new crank bearings if that's what you're talking about. You have connecting rod bearings on the big end of the crank as well as crankshaft bearings at either side of the crank
th-cam.com/users/shortsR94-IBISx8k?si=jdB_xfdXaDeLh-yk
What diameter hone do you use?
3-1/4" or 83mm.
My cam chain keeps coming off of the gear behind the flywheel. How do I prevent this
There should be a keeper on the bottom side of the crank behind the flywheel, and you should have a white-ish (often tan from the oil) chain slide on the front side of the chain galley that slips in and black one on the back side that is bolted in at the bottom and is pushed on by the cam chain tensioner on the back side of the cylinder.
@@Fixin2Ride-Official- I didn’t have the other chain slide in and that was most likely the problem will try again tomorrow. Thank you
@jadenwong27 yep that was it. The chain could also be very stretched too. They Typically should be changed when the heads are rebuilt
@@Fixin2Ride-Official- it’s actually a brand new cam chain
@jadenwong27 OH good deal. You're good then. Just make sure you crank in the tensioner first before setting up the cam timing. I use a small screwdriver and a pair of vice grips
Always put something to cover de base .IT easy to. Drop a c clip in the hole.ask me how i no !
I've only done that once and it was easy to get out being metal. Just used a telescoping magnet.
Bro this is such an awesome video, great depths were covered, keep up the good work ❤
Thanks! I really try to do my best to be in depth with the repairs I do so there's no question on what people need to do on their own. I just really wish it would make the channel grow faster and bigger so I could do more things and provide more content.
That method works but you need the engine on the bench not in the bike
Nah.
How did you figure out that the can timing was off?
I just double-checked it with the view plugs. When I lined up the cam lines with the top of the head, the flywheel marks were off.
@@Fixin2Ride-Official- thanks for the super quick reply. I am rebuilding the piston soon and I am pretty nervous. This video was a lot of help. I am most concerned about the timing marks. Last time I checked my valves I couldn’t find the tick mark on the flywheel towards the bottom of the engine. This is beginning to concern me after reading the other comments.
@jadenwong27 My pleasure! And ah. Yes, you have to make sure that the piston is TDCon the compression stroke. The punch marl on the crank gear on right side of engine will be lined up with the arrow on the case and the flywheel mark should be lined up with the notch in the threads. Use a flashlight and you'll have to get down below the hole to look up and see it.
P.S. glad it's helping and don't worry, get it all together and double check stuff, kick it over slow at first to make sure it's all moving well. You'll be fine. And I'm here for any questions.
@@Fixin2Ride-Official- Thank you so much. I was worried since this video is relatively old you wouldn’t respond. But thank you again
@jadenwong27 you bet. All I ask is that you share your favorite video and the channel in your social media accounts to help spread the word about the channel! Much appreciated!
why you put piston 12.9:1??🤔
Great question! That is the stock compression ratio piston. I first brought home a 13.5:1 but decided against it because I'm not sure how many hours are on this crank. And the increase compression is a little harder on the crankshafts. Since I've had the bike I've put at least a hundred hours on a crank and I don't know if it's ever been replaced. So when I replace the crankshaft I'll probably put a higher compression piston in it.
@@Fixin2Ride-Official- 200hours on crank with piston 13.5:1. Used Motul 7100 10w40 or maxima extra 10w40 change oil and filter every 6hours💯👌💪
Not sure if you've noticed but I ride Motocross tracks which is a lot harder than trails.
Here's how I powder Coated my Rims on this 06 CRF250r.. Check it out. th-cam.com/video/G5IJHkmjsKs/w-d-xo.html
I’m so confused. The punch mark on the right side on my bike is not set up properly somehow. I rotated the crank to the mark and the exhaust rocker was still tight. Went to the next TDC (where the mark is not visible) and the rocker had play. I tried setting the cam timing so it was according to the punch mark and lightly began to kick the bike and felt valve interference so I stopped. When the punch mark is not visible and the bike is in TDC, the timing marks on the left side are aligned. Seems like someone didn’t know what they were doing during a bottom end rebuild, and I don’t know where to start.
If you're timing marks on the flywheel are not visible at the same time as the punch mark on the crank gear then chances are your flywheel key sheared. So you need to pull the flywheel and check the flywheel Woodruff key
You can tell if you're on the compression stroke by taking the plug out and putting your hand over the spark plug hole. Air will start rushing out on the compression stroke. If your bottom end is put together right you should see a punch mark on two gears and the flywheel on the other side of the engine should align with the notch on the inside of the threads for the view hole and the right of the two lines on the flywheel. And then your cam intake lobes should be facing mostly towards the back of the bike maybe up a little bit as well as both lines on the cam gear being parallel with the top of the cylinder head.
A great idea. Just pulled the flywheel bolt and the key is still there and intact.
Is the key way in the crank lined up with the keyway on the flywheel?
Okay so I just checked and you cant see the flywheel key slot in the crank from the end of the crank with the bolt off. The crank gears can only go on in one position. So its definitely your flywheel key being sheered. It will still be there when you look at the flywheel but the bottom half of the key is sheered off and still in the slot in the crank at a diff position. You'll need to get the flywheel puller from a shop or Rockymountainatvmc.com and get that flywheel off. You can order the flywheel key from Rockymountain as well in the "OEM" section.
Check out the next upgrade to this bike! th-cam.com/video/zmILOGJ4pvQ/w-d-xo.html