I just put in a new Yoshi system, and it is great, except it sputters when I do wheelies. Does this mean it's rich? Float level? I have 155/160 mikuni jets, with needle on the 3rd clip, 620ft elevation, with no snorkel on the airbox.

 

Hmmm, I have the same pipe & I run with out the lid & use 165/170 mains, clip= pos 4 or 5 depending on temp.
You might be a tad rich with just the snorkel removed, either try clip pos 2 or try one size smaller mains & see what happens. Try removing the lid, I bet she cleans up but you'll be too lean then. If you ride it too rich you'll probably experience the same problem when climbing hills, I did when I was too rich on the needles & moved the clip to fix it. It wouldn't hurt to check the float levels but I had that problem too & the only sign of trouble was I smelled gas all the time since the one float level was way off & wasn't allowing the gas to shut off. It kept leaking out the drain hose at the bottom of the carb.

Its to your advantage to experience first hand what too rich feels/sounds like. You should always jet too rich & then lean out one setting at a time until the trouble clears, then leave it there. A tad rich is always better then too lean, cause it may be too late!

 

Check the float specs first!

 

How do I check, and adjust the float level?

 

You'd have to find out the specs on your quad as to float level height, but I'd suspect if the problem only appears when doing wheelies, you're experiencing cavitation, or sloshing of fuel away from the main or needle jet due to the extreme angle of the carb.The condition often appears when climbing long steep hills and sometimes when doing hard cornering. I wouldn't think altering the jetting would help in this case since the problem is the fuel is not getting to the jets in the first place.

 

Some people take the carbs apart and measure where the floats are.. here in Pa we just take some clear hose and put it on the bowl drain then hold it tight to the carb and open the drain screw. The level in the hose will be the level in the carb bowl..

I think it should be just a CH above where the carb meets the bowl

 

<< How do I check, and adjust the float level? >>





Take the carbs off, take the float bowls off, hold the carbs upside down and measure from the bowl mating surface (no gasket) to the top of the floats themselves. The spec is 13mm or 0.51 in.