Degreeing cams

[Guest]

When adjusting cams does anyone know how far to move the degree wheel to get desired movement in cam timing? Example--if your intake cam is at 108 deg and you want it at 105 deg how far do you move the degree wheel after loosening gear? Or is it kind of trial and error/ expierence kind of thing?.

[Mekanix]

my guess is

(initial angle - desired angle angle) *2


as in you want to move the wheel 6 degrees

(108 - 105) *2 = 6 of crank rotation to to equal 3 degrees of cam rotation

[Suzuki_Don]

Try 3 degrees initially on the crank (degree wheel). Just move it a small amount, lock up the cam sprocket, rotate the cam a couple of revolutions and then recheck. Trial and error will get you there.

It is very hard to get the cam timing perfect, if you can get within 1/2 a degree you are doing well. Often when you loosen the two bolts holding the sprocket to the camshaft the cam will move one way or the other from the valve spring pressure exerted on the lobes. So you will have lost your original settings and have to start over again. I clamped each camshaft in place to the head when releasing the two bolts, moved the crank the appropriate amount, retightened the two sprocket bolts and the rechecked to see how far out I was, etc.

But you'll work it out with a bit of patience. As an example I was aiming for 106° on the exhaust and 104° on the intake. I ended up with 107° on the exhaust and 105° on the intake. Nevertheless the bike performs really well. Pulls like a train.

[trippivot]

crank /to/ cam movement ratio is exactly 2-1

example:
you want to move the cam 2 degrees - turn the crank 4 degrees.

[trippivot]

1 more thing about doing this, re-check re-check re-check re-zero the dial and re-check until the numbers come up the same 2 or 3 times.

[Steve]

1 more thing about doing this, re-check re-check re-check re-zero the dial and re-check until the numbers come up the same 2 or 3 times.

Only 2 or 3?

.

[Dogma]

Only 2 or 3?

.

Yes, only 2 or 3. 5 Is right out!


(Never miss a chance for a Grail quote.)

[posplayr]

It is the accuracy of this pointer that allows you to converge much faster in getting the angles to repeat after only about 2 times.

http://www.thegsresources.com/_forum/showthread.php?t=139950&highlight=degree+wheel