Off idle stumble

[96desertXII]

I'm pretty sure my XII is a california model and I have a HORRIBLE off idle stumble. In fact at 2500 rpm and below the engine stumbles with any small throttle changes, big changes are ok, but little ones suck.

Any "fixes" for it? Its just an irritant for me and I would like a smoother throttle response.

[mountainman]

Well that's a tough one cause these things seem pretty lean off idle to me. Assuming there's no dirt or gunk in pilot circuit, you can open pilot screws some and gain a tiny bit there. It will help some but it really just masks over the real problem. Which is pilot jets need enlarged slightly.
Make sure your carbs are clean by running a couple tank gas with seafoam cleaner. Experiment with pilot screw enriching and see if it makes it better for ya. If you go to far rich with pilot screws it will smell rich at exhaust at idle. good luck! let us know what you find.

[Kevin B in Illinois]

Also check the vacuum hose between the ignitor and the carbs. If it is pinched or collasped it can cause a low speed stumble (mine did this and drove me nuts for a while til I discovered it).

Kevin Braddy
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[96desertXII]

Thanks..........I will check the hose, she does have 88K on her.

I will most likely rebuild the carbs this winter and get those in line. I read something about a 3mm washer under the needle helps too.