amc49
CB750 Guru
Using the wrong marks there.
Previous post here was my bad. Edited to be right.
Previous post here was my bad. Edited to be right.
Last edited:
READ the service manual, you do not use end of cam notches; you have the #1 cam lobes of BOTH cams toward the spark plug and you line up the SPROCKET punch (or index) marks with the head surface, not the end of cam ones. They are wider spaced making them more accurate.
The NOTCHES you show in pic #3 have nothing to do with cam timing AT ALL. They are miles too wide to ever be used for timing. They are machining check marks for making the cams. Nowhere in the cam timing section do you see those notches indicated to use for cam timing.
Section 6 pgs. 20
You are absolutely correct. Wrong indicator. IDK what I was thinking...
But the sprocket indicators are doing the same thing...
I have been there with other work, sometimes you look over it and it all is wrong. Just rebuilt a fuel pump on car to realize I had it totally 100% in a not working condition. A face/palm DOH! moment. I at least caught it in the review before installing it, that would have been worse. Maybe even tore it up to the loss of a $100 bill.
Use a very thin one to guarantee airspace so you can carefully measure to get the next one right. If you simply keep buying gradually smaller and smaller you may end up buying more shims that that.
If talking about ALL of them not set yet, well, have fun with that. You may well need them all over the map, it depends on how they ground the seats. Why the valve clearances get set up with the head off engine and using low pressure springs in place of the standard ones, you can rotate a single cam by hand then and pop the shims in and out easy as spit too. I use like Moroso race car valve checking springs but you can maybe find something that works at the hardware store.
Hope you're using .005" and not .003"................great.
There often can be one or two that are off a bit.
It can easily happen to anyone and even easier when you crunch numbers like that all the time. My haughtiness got in the way once when I reshimmed a zetec in a Ford Contour and almost the same engine design as these DOHC, using shims in tappets. Went to start it and it wouldn't run right. Only 2 of 4 cylinders hitting, the compression zero on the 2 not running. Yanked head after POSITIVE I had done nothing wrong and then slapped in the face when I realized I had miscalculated the metric to SAE numbers and crashed and burned exactly like the Mars satellite mission incident. The shims were too thick and just barely held the valves open.
Stupid, oh so stupid.............................I should have been quick to suspect my own work.