Got a 87 Zilla with a surge idle up ands down on its own,won't idle smooth.It is bored to 530,pipe,etc.but its got a weird idle anybody else ever have this prob? I'm figurin maybe an air leak or.......

 

Sounds like its lean because of an air leak or the way the carb is adjusted (jetted).

The first thing I would do is throughly clean the carb, take it off, remove the float bowl and pay close attention to the pilot jet and circuit, clean it but DO NOT RUN WIRE OR A DRILL BIT INTO THE JETS.

Denny

 

My 87 did the exact same thing even after I completly rebuilt it , first checked for air leaks , rubber around reeds and seals in between head and cylinder base . Talked to a few guys from this forum ( can't remember exactly who ) but one guy told me to check my crank main seals so I yanked the engine out tore it apart on the bench and sure as **** one of my main bearings had spun inside the sleeve that it fits into and eventually caused an air leak that made my engine babble reving up and down and not wanting to come bake to idle right away. So I had a machinist install some new sleeve inserts on both sides , I put new seals in and problem was solved. But it was causing my engine to run very lean which is never a good thing , unless of course you have alot of money to burn , which I don't think many of us have that there problem.

Always check the simple things first.