I finally got my '98 900RR back on the road after an 8 or 9 year hiatus. Was running great as far as I can remember when I garaged it. I've started and ran it a couple of times a year to keep things fresh but all of the sitting did cause the petcock to start leaking from the vent hole. I replaced the gas in the tank and repaired the petcock with a new oem cover set. All is good, started right up, no leaky petcock, idle's fine (slapping or knocking noise at idle which was there before I garaged it but that's for another thread). Took it for a ride and for most part runs good but I noticed its not smooth (kind of a sputter) at very little throttle when in gear. Once I get past very little throttle, it accelerates very smoothly without issues. Doesn't seem to matter the rpm's. Whether at 2k or 4 or 5k, it has the same behavior based on the amount of throttle only. It seems to be ok if I play with the throttle while sitting still in neutral and only seems to happen when in gear under load. Any ideas?

 

My first thought would be possible slow jet(s) partially gummed up.

Run on some non ethanol gas with some sea foam (or other carb cleaner) through it. That may be good enough, if not may need to pull them out to clear it up.

 

Yep, time for a proper cleaning of your jets and check everything while you're in there, it's easy! What he said above... SUPPORT!

 

I'm going to try the sea foam first to see if that clears it up before taking the carbs apart for a full cleaning.

 

Let us know how it goes...