dumbfounded

I am finishing up my top end. I had to remove the cylinder and head to inspect the piston/cylinder wall. The cylinder/piston and head are back on. I put my cams back on and cannot get the cam chain on. I put one cam back in (tried both individually) and do not have enough chain to get the other one installed. I rotated the crank several times while watching the lower sprocket. Everything looks OK. The plastic cam chain guides look OK and appear installed properly. I am absolutely dumbfounded. When I rolled the cam to YZ specs, I also had a tough time, not enough chain slack. I ended up having to remove the cam caps on both intake and exhaust to tilt both cams enough to get the chain over the sprocket. The bike ran correctly last week, so I know everything was OK. It is bizarre. With both cams installed and the chain over one sprocket, it appears there is physically not enough chain to even fit OVER the second sprocket. Something is wrong and I am clueless. The tensioner is not installed, if you are wondering. Any ideas?? :)

Kevin

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99 WR, 84 Kaw 900 Ninja, '82 Honda CB750F clothes hanger, '84 Honda Z50 "Berm Destroyer". Always thinkin' "Hell, this worked on my 2 stroke!!"

Maybe a kink in the chain on the bottom end?

I hope it's not a misfit short chain :)

No kinks. That was why I rotated the crank several revolutions. The only thing that has changed from last week is new gaskets. That couldn't do it. I am figuring I am missing something from this "Big Picture". I just haven't figured it out. When my wife, Alisa, gets home from work, I'll get her to check it out with me. Sometimes I can get so involved in something, the tunnel vision sets in. I'll get a fresh pair of eyes with me and take a second look.

Kevin... I just did my Yz timing mod on my 00' WR400 and I had the same problem. I thought I was doing something wrong too and I was just shy of removing the intake cam when I lifted the end of the cam (opposite the chain) up and and had to swing it like I was going to flip it out and to the gear on the intake cam. I was very careful and didn't kink the chain but it was tight. It just kinda flipped down and out from under the chain. Hope that helps you. Happy wrenching :)

I had a similar problem and found that I needed to turn and HOLD the screw in the cam chain tensioner to get the tensioner to stay right off. The manual explained how to release the tensioner but not that it could slip back on. Harry

Does anyone know if there is some sort of pin BELOW the crank sprocket (for the cam chain)? If there was a pin, and the chain somehow got under it, as viewed from above (during chain roatation) it would appear as if nothing was wrong. So far, I have had zero success at fixing this. I know how much slack I had when I went to YZ timing. I do not have that slack now. Everything I CAN SEE is fine. What I cannot see is under that crankshaft sprocket. I really do not want to pull the whole top end off again. I am a believer in replacing the gaskets. These two gaskets ran me $35.00. Of course my local dealer has zero markup profit off of this crap - yeah...right :) !!!!!!!!!!!!

**FLASH**

After looking down the "Hole" this morning, I see where a real potential exists which wouldcause my problem. There shouldn't be a pin under there. But, with the cam chain guides in, there is precious little room between the guide itself and chain. Unless the chain was pulled taut on the after side of the engine, and the engine cranked clockwise a couple of revolutions prior to installing the forward cam chain guide, a loop could exist under the lower sprocket. The tight tolerence down there COULD prevent any loops from being pulled through. I'll see either tonight or tomorrow. I work 1830 tonight until 0630 tomorrow. I only have a couple of hours before I leave for work.

[This message has been edited by Kevin in New Hampshire (edited 04-16-2000).]

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