Won't Idle?

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Jul 26, 2008
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Hey guys Need HELP!

I recently installed a Mikuni 34MM carb on my 850 roadster. I had her running great for the last two weeks. 950 rpm at idle. Strong kickover etc.

Yesterday she died at a light on my way to work. I rode home quick and when i got back from work it started up and seemed to idle fine.

Tonight it will start but after i remove the choke it dies immediately. If i try to keep the idle open (choke off) it starts popping aggressively and still dies.

I thought i might have clogged the main jet. I took off the bowl, removed the jet, air blasted it clean and reassembled. When i kicked it over it started on the second kick but again when i remove the choke it dies right away.

2 1/2 turns out on the air screw. Had a 950 rpm the day before. The only change was a fresh tank of gas (premium). Any ideas?

Big trip planned this weekend... AHHHHH!
If it's running normally other than tickover don't worry the cause might just be the new fuel. You guys seem to have some funny fuel. Forget the main jet or needle they don't come into play at tickover.

Try screwing the air screw in say 1/4 of a turn.

I'm getting to grips with the Mikuni VM 34 single carb on my 850. I'm rejetting this weekend on good advice from the forum (Thanks everyone).

I also had a similar suddenly good to bad running when the carb was fairly new. Choke on fine, choke off went rough and died even when warm. Turned out to be loose bolts on the manifold. I made a thicker gasket, used a light coat of Permatex and regularly check the manifold bolts are tight.

Hope this helps
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