[70oldsracer]

I'm new to the forum and just purchased an 08 TRX that wasn't running. Put the motor to TDC and from what I can tell, the cam gear has spun on the cam. The cam is in perfect condition and I saw some old threads about guys making jigs to put the gear back on in the correct location and weld it. I was wondering if anyone is still doing this and how much they would want for the service?

 

[Bullvine rider!!]

Please excuse my ignorance but why would you weld it? Wouldn’t that prevent you from being able to take it off or replace it in the future?

 

[70oldsracer]

Sorry, it’s for a friend of mine and it turns out it’s his Crf 250r that has the issue. The cam gear is just pressed onto the cam and that’s why you weld it, this way it can’t spin again. Not sure if anyone even does this type of repair. Anyone have any information, that would be great.

 

[CJM]

its not worth fixing the cam gear, if you dont get it correct you run the risk of everything being off.

new cam and weld it.

 

[Bullvine rider!!]

Sorry, it’s for a friend of mine and it turns out it’s his Crf 250r that has the issue. The cam gear is just pressed onto the cam and that’s why you weld it, this way it can’t spin again. Not sure if anyone even does this type of repair. Anyone have any information, that would be great.

Ok, but can you take the chain off after? Im not qualified to do that kind of work so dont mind my sharpness 😂.But from what ive read, I’d take CJM’s advice. Sounds like a nightmare trying rotate everything (TDC) crank etc. to get cam and gear in the correct position. Idk 🤷🏻‍♂️ wish i could help.

 

[70oldsracer]

I just thought I’d there was a company already doing it, it would be a non issue. Okay, forget that ide, do I go OEM or try the Hot Cams, stage 1?

 

[CJM]

stage 2 hotcam would be best as its more an all around cam for most bikes. stage 1 is very low end for most bikes.

 

[hoser]

Is it a stock cam? If so, definitely not worth degreeing and welding it, just do as @CJM said and buy a new one. If it’s an expensive aftermarket cam, then I would send it to Web Cams. They do great work and can get it set up for you.

usually spinning a flange is pretty rare. It generally takes piston to valve contact or some other contact issue for it to spin. I don’t know that I’ve ever seen a stock cam with stock springs spin in otherwise standard circumstances.

 

[hoser]

You

Ok, but can you take the chain off after? Im not qualified to do that kind of work so dont mind my sharpness 😂.But from what ive read, I’d take CJM’s advice. Sounds like a nightmare trying rotate everything (TDC) crank etc. to get cam and gear in the correct position. Idk 🤷🏻‍♂️ wish i could help.

It’s actually welding the flange that the cam gear bolts to to the camshaft, not the cam gear. So it’s all still serviceable.

 

[70oldsracer]

Is it a stock cam? If so, definitely not worth degreeing and welding it, just do as @CJM said and buy a new one. If it’s an expensive aftermarket cam, then I would send it to Web Cams. They do great work and can get it set up for you.

usually spinning a flange is pretty rare. It generally takes piston to valve contact or some other contact issue for it to spin. I don’t know that I’ve ever seen a stock cam with stock springs spin in otherwise standard circumstances.

I don’t see any numbers on the cam, so I have no idea if it’s stock or not.The bike wasn’t running and it looks like the chain tensioner failed. Did a leak down test and everything seems good. Brought it up to 100 psi and both gauges looked almost identical. I’m almost 100% positive that there are no bent valves. Not sure what caused the gear to spin, but when I put the motor at TDC, the marks on the cam aren’t parallel to the head.

 

[hoser]

Not sure what you mean by that last statement, there are no marks on the cam, only on the cam gear. If the tensioner failed and the chain jumped, just re-time it. I would be Leary of bent valves, but if you say it’s holding pressure you may be fine.

 

[70oldsracer]

Not sure what you mean by that last statement, there are no marks on the cam, only on the cam gear. If the tensioner failed and the chain jumped, just re-time it. I would be Leary of bent valves, but if you say it’s holding pressure you may be fine.

That’s what I meant, the marks on the cam gear should be visible on the right and left hand side of the head when the motor is at TDC. They definitely aren’t and that’s why I feel the gear spun on the cam. Let me figure out how to post pics so you can see what I’m saying

 

[hoser]

I apologize, I reread the thread and realized this is for a CRF250, don’t know how I missed that. But you started out the thread saying it’s for an 08 TRX450ER. So is it the TRX or the CRF?
I would compare the cam with another known good one, or even with pics online. It could just be that the chain jumped.

 

[70oldsracer]

Sorry about that, it’s my friends and he has a trx 450 as well as a Crf 250, so I didn’t realize it was for the Crf 250 when I first posted. On the Crf 250r, the cam gear is pressed onto the cam. The only thing I could think of that happened is that the cam gear spun. At TDC, the timing marks on the cam gear are not parallel with the head like the service manual shows.

 

[hoser]

Or again, the chain jumped.

 

[70oldsracer]

Or again, the chain jumped.

Okay, I'm going to try to explain this a little better. There is no cam chain on the bike right now, I put the cam in the bike and set it up to where it would be at top dead center just like if I was about to check the valve lash. When I look at the gear on the cam, the marks are not parallel to the head, the chain has absolutely nothing to do with it. Hope these pics help and sorry for any confusion.

 

[70oldsracer]

 

[Bullvine rider!!]

You

It’s actually welding the flange that the cam gear bolts to to the camshaft, not the cam gear. So it’s all still serviceable.

I see, that makes more sense, thanks for clarifying. 🤙

 

[Bullvine rider!!]

I just meant if it’s serviceable after welding the cam gear I.e replace cam, chain etc. i knew the chain had nothing to do with your issue. And I apologize for even commenting on it since im not helpfull at all. Im just learning as i go. I probably shouldn’t comment if i cant help. I understand your problem and i agree with the cjm,hoser , buy a new one. Trying to fix it can open up a can of worms. (Everything not lining up) Hope you get it fixed. Good luck 👍

 

[70oldsracer]

I just meant if it’s serviceable after welding the cam gear I.e replace cam, chain etc. i knew the chain had nothing to do with your issue. And I apologize for even commenting on it since im not helpfull at all. Im just learning as i go. I probably shouldn’t comment if i cant help. I understand your problem and i agree with the cjm,hoser , buy a new one. Trying to fix it can open up a can of worms. (Everything not lining up) Hope you get it fixed. Good luck 👍

I appreciate every comment and hope you didn't take my reply the wrong way. I was actually replying to hoser about the cam chain jumping.