Un-corked and still not right

I have a totally stock 650L and as soon as the engine clears a specific RPM, I guessing around 2500, the power comes on strong and sudden. I live at 6500ft and the idle mixture screw is as far out as that factory tab will allow. There's also some hesitation here and there when riding, kind of inconsistant. Is there anything I can do? I don't want it any louder and it has plenty of power for what I use if for.


Sounds like there is crud in the carb blocking the pilot circuit. Take it out and clean it. Blast carb cleaner through all the passages and be sure that they are all clear an dopen.

While you are in there you might as well do Dave's mods. All it really does is get the carb set correctly. The bike comes set very lean to pass emissions. It is simple to do and makes the bike run much better. It does not make it any louder.

At 6500 feet you might want to use jets that are one size smaller than what are recommended with Dave's mods.

Where do I find Dave's mods?

It sort of runs bad off idle like it's still warming up even when it's hot. I'd like to keep my 55mpg so if I could fix it by backing out the idle mixture screw past what the stock tab allows I'd be pretty happy, or will it take more than that?

I've decided the only thing that I want to fix is the stumble at the very bottom of the powerband. Openening the idle mixture screw to 3 turns out only helped a little. I'd like to put that back to 2.5 turns where it's recommended and shim the needle instead. Will that help?

It will never be quite right until you get a 58 pilot jet in there.

That, shimming the needle, and trimming the screw will get you there.

Drilling the slide only improves the throttle response- that is, makes the delay between turning your wrist, and the power, a bit shorter.


So, the low RPM stutter is normal? I've been told that bikes at high altitutude NEVER need a bigger pilot...that was on 4 cylinder bikes though.

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