Low-speed idle, '01 GP800R

[WayneLee800]

I have a 2001 GP800R with an SBT motor. The problem is with the idle and the transition from low to mid-range. If I use the choke lever and close the butterflies somewhat, the low-end performance improves significantly but then at higher speeds they need to be opened back up. The local dealer rebuilt the carburetors, however taking it back to them is not an option (a bad confrontation over the job they did and their charges). Once into the midrange, it runs like a scalded cat.

I assume the low-speed adjusters control the mix rate; if so, and if I open them up, how sensitive are they? Do I try ¼-turn increments, for example? Right now I don’t have the time or space to rebuild them again myself. The almost-funny part – the service manager test-rode it after the rebuild, and his feedback was “it’s still not running right.” Do ya think?

Thanks for your feedback,

[jeffg426690]

Re: Low-speed idle, '01 GP800R

You are describing a problem w the pilot jets, not low adjuster screws. To confirm, when you say mid-range it changes - what ballpark rpm are we talking about?
Really, anything at more than 10-15℅ throttle and your almost only in the low jet range as far as what's delivering fuel at that point t in the circuit. It crosses into high/ main jet in mid-range.
You could have dirty low jets, that would restrict fuel flow - which in turn choking it reduces air to get it to run. You can't necessarily see dirty jets by looking at them, a few thousandths of old fuel varnish is all it takes to reduce the amount metered by the jet.
Bad news is, your gonna have to go back into the carbs no matter what...

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