Valve Timing

EnduroJoe

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It seems that I really screwed up on my CAM installation with my engine rebuild. After getting the engine back in the frame I was setting the valve clearances when I noticed that the valves did not seem to be opening and closing at the correct points. I thought we were being very careful aligning the TDC mark and the notch on the cam gear during installation. Right now the only external indicator I have is the pin hole that would be used for the timing advance. That pin hole is at the top or bottom when the pistons are at BDC :-( and at the 3 and 9 o'clock positions when the pistons are at TDC. The valves appear to be opening and closing 180 degrees out of spec.

My question is, does that pin hole line up with timing notch on the cam gear which should have been at the top with the pistons at TDC? Other than trying to build a make-shift degree wheel to try to verify my worst fears, knowing where that pin hole lines up should tell me everything I don't want to hear before tearing it all apart again. The pictures I have seen of 650 CAMs on-line have a key-way slot rather than a pin hole, but they appear to line up with notch on the gear.

Would it explain my problem if I somehow swapped aligning the TDC mark on the cam with the one that should be alligned with the top plane of the head?
 
Yes, that pin hole lines up with the notch on the sprocket, also with that key-way slot on the other end of the cam. When assembled, you won't be able to see the key-way slot though, the cam bearings cover it .....

1ckxoLM.jpg


Personally, I don't even use that dot on the right side of the sprocket, just the notch on the left. It's much easier to watch that and the timing marks at the same time.
 
Yes, that pin hole lines up with the notch on the sprocket, also with that key-way slot on the other end of the cam. When assembled, you won't be able to see the key-way slot though, the cam bearings cover it .....

1ckxoLM.jpg


Personally, I don't even use that dot on the right side of the sprocket, just the notch on the left. It's much easier to watch that and the timing marks at the same time.
Just make a mark on the left side where the dot is on the other side.
 
As I expected to find, I had set up the cam with the punch mark aligned with TDC rather than the notch. But now that I am reading the book again and correcting my mistake, I have another question, more for clarification and possibly to help someone else than anything. The "Haynes, Owners Workshop Manual" that I have says to have the "left-hand cylinder at TDC on its compression stroke and both valves will be closed", but when the notch on the cam gear is at the top, this is the case for the 'right-hand' cylinder.. not the left. The left is just finishing its exhaust stroke and starting the intake stroke with both valves partially open.
The "Clymer service manual" that I also have also says the piston should be on the compression stroke, but it does not say which one.
Is the Haynes book wrong and Clymer just did not get specific enough?
Thanks again for all the help.
 
Yes, the Haynes is wrong. What you are seeing (right cylinder at T.D.C. on it's compression stroke) is correct.
 
If you need a Yamaha factory manual there are free downloads listed in the tech section
 
I was just questioning the Haynes manual this morning on this very topic,thinking OMG, did I install he cam incorrectly? With help from reading texts from XJWMX and the excellent valve adjust videos from littlebill31,
I'm confident I have done it properly. Thanks guys. What a great resource this is. Next step is installing the engine back into the frame. Timing adjustment next after that
 
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