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07 CRF450R timing chain replacement question

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I have an 07 CRF450R that needed a valve job. Sent the head in to AS Racing for TRX valves, rebuild and valve shimming, etc.

 

I followed this guide, but the 2007 450 has that weighted advance thing on the timing gear and different cam retainer bearings since the housing is mounted around the bearings.

Guide: How To Remove a Honda CRF250X Head For Shipping

What the guide says: (different year crf250)

clip_image050.jpg

 

When I was taking off the cam shaft bearing retainers, I could not get the timing chain off and the came out. I had to really work it around with my hand while having the tensioner all the way clockwise to get it off. I am worrying I may have stretched the chain by putting ~30lbs of force or so on the chain to slip it off (yes, I made that number up). I should have unbolted the timing gear on the cam shaft, but the gear kept turning on me, so I couldn't undo the bolt.

 

To replace this, should I just buy an OEM chain and tensioner for ~$150? Should I get a manual one? Aftermarket?

 

Once I am putting it back together, I will follow the timing thread in this forum.

 

Any suggestions on timing chain replacement  or other service while I have it apart are appreciated.

 

I have limited funds at the moment and hope to do more engine work next year.

 

I probably have about 60 hours on the engine.

 

Thanks!

Edited by Eric Schrader

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Yea you have to hold the crank with a allen wrench on the other side of the engine while you undo the cam bolts to remove it. I would get a new tensioner cause they are known to fail. I have had mine fail and a friends.both 05's with more hrs but still. Doubt you stretched the chain. But if you put it back together and the chain has alot of movement still, then replace it.  And if you can swing a manual one. do it. Never will have a problem again

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I dont think the manual has that tip in it. The T handle allen wrenches are awesome. You can hold the handle with your left hand while undoing the cam with your right. And if you can swing it money wise just gte a new chain,

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I dont think the manual has that tip in it. The T handle allen wrenches are awesome. You can hold the handle with your left hand while undoing the cam with your right. And if you can swing it money wise just gte a new chain,

I have a bunch of T handles. no new chain here, having a garage sale Saturday just so I can go racing Sunday :)

 

Should I oil any places on the head, like the valves, before putting the head back on? I read an article from JCR saying a lot of people mess up the heads by not oiling them when putting them back on after rebuilds.

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I understand. Im at the end of a full suspension rebuild/tires/bearings. Doing a bunch of side jobs and the money just goes from his hand to my hand to whomever I am buying parts from hands. Never sees the pocket haha.Yea its always good to pour some oil over the valves/cam assembly. Cause it will take a second or so before the oil gets pumped up there after starting it. Just make sure you measure what you pour in so you dont overfill. Or just pour the whole 700cc or whatever it is through the top.

Edited by ARGMISTER

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the OP was too difficult to follow for my aDD, I couldn't tell if the tensioner was removed or not.

if you remove the cam chain tensioner from the cylinder the job goes much smoother.

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I put it back together with the OEM timing chain and tensioner. It wouldn't start at first, but I bump started it down a hill. Started on its own for the next morning about 10+ times in about 4 hours. Then I kicked it and hit the kill switch (30 seconds before the race started) and it died- kinda of a panic kick and stall last minute to warm it up. Maybe I freaked out and kicked it funny. Wouldn't start after that and DNS the race. That's what I get for being cheep. Ended up spending $150 to get down to the race, sign up and gas. Learned a lesson. Don't be cheep. Need to take it apart but it sounded not so good when it stalled, like a cat dying. I think the timing chain slipped a tooth. I half cleaned the carb (couldn't get the Philips float bowl screws out) so maybe that was it too, but I am pretty sure it was the chain that slipped.

Edited by Eric Schrader

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Sorry man. With these bikes you def have to have a "do it right the first time" kinda attitude cause everything is so touchy. I rebuilt my buddies crf450r and he didn't buy a chain nor tensioner cause he insisted it was fine. Sure as shit 30 minutes in his trip to the dunes after it was done the tensioner let go and he said his bike sounded like it was falling apart inside.  Yea the screws always get stripped out after about 3-4 times of removing them. You can get a hacksaw blade and cut slots in them for a flat blade,then get new ones.

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The chains don't stretch but the pins wear a little and the plates get sloppy. More than likely you just missed the cam timing. Check the sticky on this forum and there is the correct orientation to see when the timing is correct.

 

Don't try to use the dot on the right side of the engine. It can put you out in left field pretty easily. Use that for turning the engine over, but to check the timing, use the small plug on the left side to see the flywheel.

 

Its a heck of a lot easier.

 

I wont use an old auto tensioner. Period. Its either gotta be new, or a manual.

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