Yamaha Yzf Cam Chain Problems?

[woodsy]

During the last couple decades I have rebuilt dozens of Honda 4 strokes and most of the time this included installing a new cam chain. The way that I check a chain IN BIKE is clean a section of it it real well to remove the oil, hold the chain firmly between my fingers (capturing a few lengths between the index/thumb on left and right hand) and push/pull while watching for play between the pins. Most of the bigger XR's use a hypo chain (multiple plates forming a gear type of area for the cam sprocket to land in) and this method of checking has ALWAYS proved true for me.. This style of chain is very expensive/heavy duty but still suseptable to wear problems resulting in some MAJOR concerns if not properly maintained (replaced at stated intervals)..
Now for the Yamaha question.. I was at a friends house helping him rebuild his 2000 YZF. He had a top end noise that majorly increased with no strain on the motor. He swore that it was rod related - I said it sounded to light for a wristpin/not low enough for a rod bearing. I suspected cam problems.. Once down I was VERY impressed with the internals of the Yam - except for the cam chain!! It was tiny!! Looked like something out of a Honda 70 motor.. I did the exam and found plenty of movement between the pins. Got it out and it definitly showed major ARC on the bench!! My buddy is still going for the rod replacement but I told him he should hang on until I have a chance to run this little survey!! So How bout it ch'all? Anyone else had simular problems with the cam chain stretching? Could this be a "weak link" (place my smily here)..
Woodsy

 

[endosports]

woodys,

Not to get off the subject but did you check the valve clearences first?

 

[woodsy]

Yes and a very good question!! I REALLY liked the new disc style of valve clearance adjustment (except those pucks are tiny). Definitleya PLUS over the ol loosen the lock nut/adjust the rocker/tighten the lock nut/loosen the locknut and reset because when you tighten the locknut it throws the setting out of wack routine!!!). It was the first thing we checked!
Woodsy

 

[Stumpy]

I had the same problem. Valves checked good, so I changed the chain and the tensioner and the problem went away.

 

[E-Ticket]

How many miles/riding hours on the engines to have this show up?

(understand it's probably just a guess.)

Also, any idea if this problem is repeated in the WR400/426/450's?

thnx! - E-Ticket

 

[holeshot]

It's common for the '00 YZF (and maybe earlier years) to make a clicking sound when the counter balancer gear key develops sufficient slop so that the gear rotates back and forth on it's shaft, making a disturbing noise. :debil:

I replaced my CB key twice. It took 95 cents in parts and 4 to 5 hours of my time.

'01 and later years use a spline drive for the CB gear, so they don't have that problem.