is it alright to put premium in my piped jet and filtered z400 with out making any adjustments? or it not what needs to be adj'd?

 

premium fuel that is. Does anyone know?........

 

no you are ok...actually since you have those mods, you should have already been running it with the stuff...you will find your quad will run much better with premium

 

my small engines teacher is a highly experienced motorcycle mechanic, and he used to race. i asked him the same question before and he said that regular unleaded is the best. but its your money so do what you like! hahah. with these gas prices id be using unleaded anyways.

 

As long as you haven't changed the compression or anything, running the minimum grade Suzuki recomends is still fine. Just putting a pipe and filter on does not mean you need to run premium. Chances are you will actually make a bit more power on the recommended grade.

 

My z400 has never had anything but 91-93 octane and after a year a a half the thing still runs perfect. Original plug and everything.

Using lower octane in a higher compression engine can cause your valves to need adjustment quicker. Octane regulates ignition and keeps timing level, lower octane in a higher compression engine can cause pre-detonation which can foul plugs and upset valve timing.

Any engine builder worth his salt will tell you when you get above 10 or 11:1 compression you should run super.