my 87 zilla has a pipe and silencer.open air box.k&n air filter and boisen reeds.does aneyone know what jets i shuold have.i live in mich. altitude here ? dont know.the stock carb has a 470 maine jet .some people say its way to big.allso can the timeing be adjusted if so how?and last on the opposite side of the power valve window on the case is a dial that turns. is this to adjust the valve? where do you set it . can i get some power out of this.thanks for the help.[img]i/expressions/face-icon-small-confused.gif[/img]

 

I'll try to help you out...

First of all, each jetting situation is unique. You can't just go by what someone else says is too big! Depending on the mods the machine has, pipe, reeds, carb, etc... Is it running rich? Blubbering under misc. throttle positions? Those are the types of questions you need to ask yourself. Don't depend on what someone else is running, because their situation could be quite different. (Porting, etc.) Example: Back when I ran the stock carb, I used a 34 pilot, 460 main jet at 4,500 feet elevation. My situation changed significantly with porting, bigger carb, different reeds, different pipe, etc..

Please, please, please do some research on proper jetting techniques. learn to 'read' the spark plug and piston wash, and the effects of each jet (Pilot, main, needle)
The net is a wealth of information.. Don't be afraid to learn how to do it yourself... It's really not that difficult.. Just be careful and make one change at a time, and verify it's affects before doing another.

The timing can be adjusted, but you'll need a flywheel puller to do it. Unless you're running some pretty serious porting, and bigger carb, etc... I'd leave it where it is (At TDC).

Exhaust valve adjustment: with the two screws loose and the **** set at zero (You can pull the **** out of there to make sure spring tension is zero) turn the **** 360 degrees counterclockwise (from the zero mark) and tighten the screws. (That's one turn counterclockwise) and that's it!
Pretty simple. The valve should actuate at approx. 4,500 rpm unless it's all gummed up from oil gunk... If that's the case, it will need to be disassembled and cleaned. The valve should rotate freely. (Using a good quality oil will help avoid this problem)

Hope this helps.

 

GNJEFF, My brother (zillalover) has a bike w/ almost exact same mods as you. I belive he is running in the 370-380 range on the main jet. This should be a general starting point for you . I think our elevations are about the same. Probably want to start a little richer, just in case....