Hey Guys,

I'm not sure if anyone is active but it worth a shot. Im working on a 2006 GS500F.

Did a carb clean and installed a new carb kit. Bike runs smoothly up until 8000 / 9000 RPM where it will start to missfire. It doesn't stumble or anything, its just a momentary missfire. If I keep the throttle open it just keeps missfiring every 2 seconds.

Im thinking ignition? Any direction on what to test first would be appreciated.

How are your valve adjustments?

Hey!

Thanks for the reply. I wan't sure if anyone was here.

An update, I increased the piloit jet from 17.5 to 20, and main from 130 to 132.5

That didnt change anything. I tested the ignition coils and timing gap and resistance of the pickup coil. All are in spec.

One interesting discovery is that the missfire doe not happen when the airfilter is removed. It has stock airfilter and aftermarket exhaust but I dont see how this could cause a missfire still.

I didn't even consider the valve gap could be the issue....they would have to be too tight for this to make sense. Compression is within spec though.
Worth a check though ,this will be a fun fix.

 

Aftermarket exhausts always make things tricky to tune. I would start by putting back the stock exhaust and seeing what happens.

I chased my tail for a year and a half on a misfire and it turned out to be a pattern air filter. That did it. Went back to the factory air filter specific to my year and everything rocked and rolled.

Agree, unless you know what you're doing...return back to stock to get a baseline. I purchased my 2002 Suzuki GS500 and it had a lean misfire...then I realized the previous owner put in an air filter from the pre GS500E models...2002 year OE filter has a restrictor ring at the top, which solved my issue.