Jump to content
Sign in to follow this  

I think I spun my cam...

Recommended Posts

I put my motor back together with a 488 kit due to a failed cam chain tensioner. When it failed it skipped a few teeth and hit the intake valves, there was so much force involved that the intake valves stayed open and the piston came up to say HI! Once that occured the piston could travel no further UP so it deciced to go FORWARD and broke the front of the cylinder with the piston skirt (piston looked OK but I am not going to chance it since the damage may not be visible)

So I got a new timing chain, new intake valves, and 488 kit, and put it all back together, I noticed that when I set all the marks to TDC the cam lobes are trying to open the intake valves as if the cam is advanced about 30 degrees or more, so anyway I lined it all up even though it didnt seem right, went to stroke the kikstarter to make sure the motor would turn and I could feel the piston hitting a valve..so it does in fact seem like my cam os out of sync with the flange that mounts the cam sprocket.

Is there any way to reset the timing and TIG weld it back on so it cant slip again? I just have no idea how a person would be able to line it back up since I didnt see anything that marks where it was before since it is a pressed on fit not made to ever move..

And I though I was going to be able to fire up my bike last night....:lol:

Seems the best mode of action is to get a new cam since the big bore kit would work better with a larger than stock one, still waiting on Ron Hamp to respond to my PM for a cam but I think thats not gonna happen, I tried to contact him for my last bike but I couldnt get a hold of him, I guess he doesnt want my business...so it looks like a Hotcams Stage 2 or 3 should do the trick, along with my freshly ported head the thing should be a beast!

Anyway just curious if anybody else had ever seen this issue with the cam spinning on its mounting flange?

Share this post


Link to post
Share on other sites

It does happen. The cam gear can spin on the flange.

You'd need a degree wheel and the cam specs to reset the cam gear. Or simply get it close on a new tooth instead of were it was, but its going to be much easier for you to just buy the new cam.

Go with the stage 3 Hotcams if you go that route.

Dont get all crazy with the jetting. I bet you dont even need to change the pilot, and the main jet could end up smaller than stock because of the more dramatic intake pulse.

Share this post


Link to post
Share on other sites

yes, my 04 motor .. and it never had a failure, just a gabillion hours. I tack welded the sprocket holder to the new cam

Share this post


Link to post
Share on other sites
It does happen. The cam gear can spin on the flange.

You'd need a degree wheel and the cam specs to reset the cam gear. Or simply get it close on a new tooth instead of were it was, but its going to be much easier for you to just buy the new cam.

Go with the stage 3 Hotcams if you go that route.

Dont get all crazy with the jetting. I bet you dont even need to change the pilot, and the main jet could end up smaller than stock because of the more dramatic intake pulse.

I actually changed the main from a 178 to a 172, so I figured I would start there. I am going to order a stage III cam since Ron Hamp doesnt respond to PMs so I should have that next week, probably going to TIG the new cam to be sure it wont happen again.

yes, my 04 motor .. and it never had a failure, just a gabillion hours. I tack welded the sprocket holder to the new cam

Stage III on the way, gonna tack it...

Thx guys, this motor failure has been full of surprises.....:lol:

Share this post


Link to post
Share on other sites

So if I was looking at the cam would the flange line up with the cam lobes as far as the hole in the flange being clocked at about the same place as the intake lobes highest point?

If so my cam is SUPER out of whack...I just dont feel like tearing into my 05 just to look at the cam...thx.

Share this post


Link to post
Share on other sites

for what your doing a stage 2 or 3 cam will work just fine.you would have needed a spring kit to match my cams also .Most every thing i have made now is for dirt track or SM all other components go through TUF for mx.

Share this post


Link to post
Share on other sites
for what your doing a stage 2 or 3 cam will work just fine.you would have needed a spring kit to match my cams also .Most every thing i have made now is for dirt track or SM all other components go through TUF for mx.

Ok got it, thought you had a lot of off-road stuff for some reason, I checked the TUF site and it had only 09 and up cams..

Thx for the reply, I always try to give people on the forums my business before the big guys..

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×