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Valve timing marks

Hillbilly Bike

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I'm doing cam timing a an 81 750....I have a reprint of the factory service manual but the images aren't all that clear....I assume this correct crankshaft position, both sprockets with the timing marks horizontal and number one cylinder intake and exhaust lobes facing the sparkplug...Thanks

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Yes. Consider that the chains stretch in use and often the sprocket marks will sit on one side or the other of the head flat. You choose the side (slightly retarded) that reflects a stretched chain. One sprocket (front) may retard slightly more as it is a far longer chain and will have more wear as a result.
 
Thanks...I did notice while the exhaust timing is exact the intake is very slight retarded...Maybe a degree or two and might lower the power peak a few hundred rpm..Nothing to be concerned with. I also replaced the valve guide seals and rings due to age.The guides and bores were in excellent shape..........I was surprised to find a primary Morse chain instead of gears on a Japanese machine....
 
Virtually all Japanese motorcycles use a chain to drive cams, only a few use gear to gear, or belt. Maybe you were referring to the flat link plate chain rather than roller chain like on rear wheel drives. That started around '80 or so and many bikes began to use them around then.

Intake cam retarded RAISES the rpm level and peak not lower, you advance to do the latter.
 
Virtually all Japanese motorcycles use a chain to drive cams, only a few use gear to gear, or belt. Maybe you were referring to the flat link plate chain rather than roller chain like on rear wheel drives. That started around '80 or so and many bikes began to use them around then.

Intake cam retarded RAISES the rpm level and peak not lower, you advance to do the latter.

Yes, the primary drive, crankshaft to transmission............Yes retarding the intake time raises rpm power band...my misprint..
 
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