Xr650r mikuni tm-40

[Billy650r 0]

Hey guys,

Getting pretty frustrated with this carb. The bike simply won't idle with it. I've tried almost every combo of jets you can think of. I just must be missing something.

Any local guys doing carb tuning?

[TrophyHunter 15]

I'm sure you probably covered this in your attempts, but if not, I made sure I rode the bike to operating temps and took a screw driver along for the idle adjustment once warmed up. All the way in, then back out until it stumbles, in a half turn. I was 1 1/2 turns out on my DR650 for a good idle.

This assumes the proper sizing based on airbox (mods), filter type, exhaust mods, etc.

If it's a used carb, there may be other wear parts on it that need replacing. I'm no expert, just a bumbling garage mechanic.

[TrophyHunter 15]

To your point, Jim Martin, at Martin Motorsports in Santee, rides an XR650R so may be able to dial it in for you.

[Billy650r 0]

I'm sure you probably covered this in your attempts, but if not, I made sure I rode the bike to operating temps and took a screw driver along for the idle adjustment once warmed up. All the way in, then back out until it stumbles, in a half turn. I was 1 1/2 turns out on my DR650 for a good idle.

This assumes the proper sizing based on airbox (mods), filter type, exhaust mods, etc.

If it's a used carb, there may be other wear parts on it that need replacing. I'm no expert, just a bumbling garage mechanic.

Ya I've tried just about everything. Been wrenching for a good while and this is the first time I'm actually stumped.

[Reximus 10]

Are the valves in spec?

[Billy650r 0]

Are the valves in spec?

Ya valves are good. Double checked those.

The bike was running perfect with the stock carb. It's just the idle circuit on this pumper is all out of whack.

[Wierdrider 187]

http://martinsmotos.com