slipped a cam chain aaarg!

[skids]

My favorite ride (don't tell my wife), the Beast, slipped a cam chain. It all started out with an oil leak. I sealed the end plug in the tensioner and oil still leaked. The oil looked as if it might have been coming from either the tensioner mounting bolt or its gasket. OK, that is simple enough to fix... I aligned the timing mark to "C" and removed the tensioner, cleaned-up the gasket mating sufface, cut a new gasket and applied some Yamabond, cocked the spring, mounted it, released the stopper bolt, tightened it to 52 inch lbs, tightened the buddy nut to 75 inch lbs, and gave it a rest over night. I started her up this morning and I could HEAR the chain! Then, she died. I cranked it again and she spun fast -- obviously without any resisting pressure. I suppose I have to get after that. What a mess of a job THAT is going to be. Wish me luck for no valve damage.

[Geezer]

Re: slipped a cam chain aaarg!

Originally posted by skids
My favorite ride (don't tell my wife), the Beast, slipped a cam chain. It all started out with an oil leak. I sealed the end plug in the tensioner and oil still leaked. The oil looked as if it might have been coming from either the tensioner mounting bolt or its gasket. OK, that is simple enough to fix... I aligned the timing mark to "C" and removed the tensioner, cleaned-up the gasket mating sufface, cut a new gasket and applied some Yamabond, cocked the spring, mounted it, released the stopper bolt, tightened it to 52 inch lbs, tightened the buddy nut to 75 inch lbs, and gave it a rest over night. I started her up this morning and I could HEAR the chain! Then, she died. I cranked it again and she spun fast -- obviously without any resisting pressure. I suppose I have to get after that. What a mess of a job THAT is going to be. Wish me luck for no valve damage.

Pull the timing cover and the valve covers then turn it over with a wrench so you can verify the problem. It's possible the starter drive crapped out on you just after you fixed the leak. Coincidences are a bitch.

Geezer

[strom]

kaka happens. I hope it's something trivial.
Just no more starter or kickstarter or anything till you figure out what it is.
I got two bent valves, wanna see?

LP

[skids]

Well, I have to say that I am sure it is not the starter slipping. I know what that sounds like. It was turning the crank. After much ado, I aligned the cams at TDC. I want to check the valve shim clearances before I button it back together and try it. I REALLY want to try it right now, but with the cam cover off, it would turn my whole garage into a well-oiled machine! I'll just wait until I have a little more time. I did have a little trouble aligning the dots on the cams with the arrows on the cam bosses. When the dot on the intake cam was right on, the dot on the exhaust cam was about 0.092 to the left. I figured that it would be closer to perfect if I moved the exhaust sprocket one more tooth clockwise on the cam chain while keeping the intake where it was. (40% too far to the right is better than vs. 60% too far to the left).

[crawlspace2112]

this always screws me up, the motor turns counterclockwise on this bike correct? that means by moving the mark to the right you are advancing the timing of your cam by a fraction and vise versa to the left. exhaust timing...staying open for that little bit longer causes overlap between the exhaust to intake stroke transition. i'm sure the engineers at yamaha would have already put overlap in the cam timing via the shape of the lobes but would it really hurt to have the extra timing? do you have a lot of miles on your cam chain? could that be all stretch in the chain? have you done a compression check lately? if you have i would check it again before lighting it up see how it compares or at least it will tell you how your timing is, if it's on the low side i would say try to time the cams closer if that has no effect then you may be looking at valves (hope not). good luck! i want to know how it comes out because i'll be timing my cams this week too my rebuild is at this stage right now

[uk1.1s]

Cam timing

Skids - done the cam timing on my XS many times (don't ask).

Dots on the cams don't line up exactly - sometimes a smidge out (but only a smidge). As you are finding, move it a tooth and it's significantly out. If you suspect that the cams are out still then turning the engine over a few revolutions - (maybe 4-6) - you may notice that the cam dots get further out of alignment. When they are spot on (as spot on as the marks get) then they will be darn close and there will be no changes on turning the engine over several times.

Turning with a wrench on the end of the crank should make the chain slip again if you have a problem. Normally you should beware as even a low speed tangle of valve heads and the piston crown will bend some (however slowly it happens and optimistic you are). As you may have had this happen under starter speeds, harm has been done if they clash on an XS (they do on a Z1000).

I found on my bike that when adjusting the cam chain tensioner - retightening somehow backs off the position and the darn chain sings for all it's worth. Try running it briefly with the tensioner on spring power (if you see whay I mean) - if my experience is anything to go by all will quiet right down. You then may have to be diligent in getting that bolt tightened up. I have't sealed my tensioner plug - so take it off, and apply a little pressure at the back of the tensioner whilst fixing it up.

Other tips:

1. Running with the valve/cam cover off makes less mess than you's think... but only try it briefly as oil is not getting exactly where it should on the cams. Sometimes a useful exercise.

2. Beware of overtightening the bolts holding the tensioner onto the block.... they can strip if you are over zealous.

Good luck

[strom]

How's your primary chain?
When I had my engine apart, I replaced mine... bout 1,5-2 cm stretched and a link missing in the middle.

LP

[skids]

Just to lclose this thread for now, I found that after aligning the cams at TCD, I checked the shim clearances of the valves. The exhaust shims were all OK, but the intakes were all excessive (way out). I had to use shims 305 and more just to get them close enough to perform a compression test. Yup, you guessed it, all were ZERO compression. I just do not know what I did wrong with the cam chain adjustment. I was ultra careful with torques and there was some travel left on the adjuster ram (1/2 inch or so?). I suppose I will either look for a good headd or contemplate rebuilding the head and cam chain. The Beast was my favorite of the 3 xs11000's hat I ride.

[Geezer]

Originally posted by skids
Just to lclose this thread for now, I found that after aligning the cams at TCD, I checked the shim clearances of the valves. The exhaust shims were all OK, but the intakes were all excessive (way out). I had to use shims 305 and more just to get them close enough to perform a compression test. Yup, you guessed it, all were ZERO compression. I just do not know what I did wrong with the cam chain adjustment. I was ultra careful with torques and there was some travel left on the adjuster ram (1/2 inch or so?). I suppose I will either look for a good headd or contemplate rebuilding the head and cam chain. The Beast was my favorite of the 3 xs11000's hat I ride.

A good XS11 is worth spending a couple hundred to do a valve job on. I wish I still had access to a dealership parts department. I'm sure there is another Yamaha that takes the same or almost the same valve. I've done it to many times in the past not to think it's still posible.

Geezer

[mitch]

Geezer

Geezer you can compare all years and models at the yamaha-motors site, it gives you part #s just go to the parts section click on the year and model and click on valves. HTH......MITCH

[Geezer]

Re: Geezer

Originally posted by mitch
Geezer you can compare all years and models at the yamaha-motors site, it gives you part #s just go to the parts section click on the year and model and click on valves. HTH......MITCH

I used to wander the parts department with a dial caliper if I was trying to crossreference parts like valves. Many times the part numbers wont crossreference in the books.

Geezer

[TopCatGr58]

Hey there Skids,

Ben just got a set of valves, both intake and exhaust from the following site, said they looked like Old stock, but they had them!
http://www.cyclewareables.com/

They are Vesrah valves, said Partsnmore didn't carry them anymore, IIRC!? HTH?
T.C.