Shimming Woes

[The Prophet of Doom]

Time to do shims which I've not done before.
Armed with the instructions, shim tool and feeler gauge I set to it.
Measuring went OK, except 2 sets of feeler gauges disagree with each other which is annoying more than anything.

Think I've got everything right with the shim tool dot mark lined up with EX then rotate anti-clockwise
It rotated till the end of the shim tool just peeked around the bottom tail sticking straight up, (seems dead in the centre of the buckets) and rotating stopped.  the buckets have not depressed and theres no way to get the shims out - they only have a tiny bit of movement. 

I thought I was being too gentle so leaned on it a little bit. Now the whole thing is locked up and the flywheel bolt is spinning off if I try to go further anticlockwise.

Any ideas where I went wrong and what the hell do I do now? Remove the cams?

[Rikugun]

It appears the tool's ramp is not engaging the buckets sufficiently to depress them. In order for that to happen, rotation would need to continue but the long tail appears to be hitting the head stopping any further rotation in that direction. On that particular one, I'd install the tool from the other side and spin the cam in the opposite direction. The tool I've got appears to have two reference marks, does yours?

As I recall there is one position per head that requires attacking from the opposite side due to a casting that interferes with rotation relative to the other position on the same cam. I'm not sure if that's the case here but worth noting. It might be easier to ignore the manual instructions and visualize on a case by case basis where the tool needs to be positioned to depress the buckets sufficiently while remaining aware of any rotational obstructions, lobe position and of course leaving room to work and extract the shims. Easy, right?   ;)

I'm not sure if it's just the picture angle but it also appears the tool is engaging only one bucket. It sometimes takes a few tries to get it nestled in there correctly and only a subtle shift makes all the difference. I'd back the cam off in the other direction to extract the tool and try it from the other side.

[Re-Vision]

Before the Postal Service stole my shims and tool, I familiarized myself with them and I believe Gary is correct in everything he said. Insert the tool from the other side and make sure the tool depresses both buckets. Should be a smooth operation.    BDC

[The Prophet of Doom]

Thanks guys. 
Currently the tool is jammed in there.  Any idea how to get it out?

[Re-Vision]

I suspect your tool is wedged in, try rotating the engine while applying force to unwedge the tool.    BDC

[The Prophet of Doom]

I'll try that tomorrow.  If it's totally wedged in there I'll have to loosen off the cam I think.  Grrrr

I hope you managed to get compensation from the Post Office.  Makes me nervous about lending my tool via post, but we can't be too precious about things I guess.  At least they are still available.

[Re-Vision]

I'll bet if you pry up on the tool while rotating the cam, it will come out. Don't ship shims with your tool, they think they are stealing coins.     BDC

[The Prophet of Doom]

You bet correctly, the tool is free,  Whew!  Thanks Bobby.
Six years on RoV and I don't recall ever reading that the instructions for shimming are incorrect

Looks like the cam timing on the rear cylinder is out though so I'll need to jiggle around with that.

[Re-Vision]

Your tool doesn't look the same as mine did, is it an official Yamaha Vision tool?    BDC   

[Rikugun]

When I read you'd managed to loosen the flywheel bolt I figured you really got after it! Glad to hear you got the tool free.  :)

How far off is the timing - half a tooth? one tooth? Can you get a pic showing it? Does it look like chain stretch or has someone been in there before you?

[The Prophet of Doom]

Your tool doesn't look the same as mine did, is it an official Yamaha Vision tool?    BDC   

Yes it's a genuine Yamaha - direct from the dealer with a Yamaha part number sticker and everything.

[The Prophet of Doom]

When I read you'd managed to loosen the flywheel bolt I figured you really got after it! Glad to hear you got the tool free.  :)

How far off is the timing - half a tooth? one tooth? Can you get a pic showing it? Does it look like chain stretch or has someone been in there before you?

Has someone been in there before me? Hell yes.  Half of what I do to this bike is undoing the shit work that the PO did, and interestingly he was a professional mechanic and spray painter - all I can say is I feel sorry for his customers.  For example he sprayed the tank ON THE BIKE! and didn't even bother masking the frame much.  Wrong screws everywhere, wires just twisted together with a bit of tape, extensive use of GLUE.  I could go on and on...

When the front is at the T mark, the cams registrations look perfectly aligned to the marks on the clamp (Pic 1)
When the rear is at 2T mark (Pic 2) the intake looks about 1.2 a tooth out to the left (Pic3),  exhaust looks about 1/2 a tooth out to the right (Pic 4)

[Rikugun]

Hmm, that does look a little off.... :(  It will be interesting to see if it runs differently once corrected.

Regarding tools - a pic of mine below and a link to another tappet tool discussion:
http://ridersofvision.net/rovforum/index.php?topic=1882.0

[The Prophet of Doom]

Not entirely sure of the procedure for this - I presume I undo the tensioners first?
I'm thinking I need to move a tooth on the bottom by dropping the chain a bit and lifting it up, then fit the cams in place exhaust, then intake so the marks line up?

[cvincer]

I removed the chain guide ,    removed the tensioner   & found I had enough play in the chain to (with a bit of wiggling) turn the cam & re-locate the sprocket tooth into the next chain link; remember the chain between both sprockets  must be tight .  I then stuck my finger in the chain tensioner hole to tighten up the chain & ensure that the punch marks on both cam sprockets were lined up with the index marks on their cam clamps.       When you have got the cam where you want it, & have replaced the chain tensioner (remember to push its shaft in hard against the the chain) ,  turn over the engine by hand (socket on the flywheel bolt) several times to check your adjustment has not resulted in the piston hitting a valve.    A compression test before & after adjustment might be a good idea.

You talk about moving the chain around 1 link on the bottom cog (deep inside the engine) ........ using a spare engine with its
cylinder heads removed I tried this ...... it's not possible.    I reckon the engine would have to be completely stripped to do it.

.

[fret not]

You have to move the chain on the cams.  After all, THEY are what you are trying to get in synch with the crank.  Crank and piston position are what you use for reference for setting other things like timing and valve clearance adjustment.

[The Prophet of Doom]

Thanks for the feedback guys, but I don't get it.
If you look at the pics above, when the flywheel timing mark is dead on, then both cams are what looks like 1/2 a tooth out.  How can I move a cam half a tooth?

[fret not]

Is the cam chain tensioner in place?  Adjusted?  Any slop in the chain can allow significant error in the reading.

[Rikugun]

Is the cylinder the tappet tool got stuck in the same that the timing is off? If yes, was the timing off prior to getting the tool stuck and subsequently free? Have you tried turning the engine over in it's normal direction a few rotations and re-check the cam timing marks?

If you rotate the engine against it's normal direction how much delay is there before the cams turn and is the delay the same front and rear cylinder?

... the intake looks about 1.2 a tooth out to the left ...

When first I read this I wondered how you measured so accurately - one point two teeth... After looking at my keyboard I realize it was a typo.  ;D  ;D 1/2 tooth isn't so bad  LOL

[pinholenz]

Hi Rohan, you will guess that I have more than a passing interest in this! How has the issue unfolded?