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mxgobig

Surging Idle? TPS?

7 posts in this topic

‘07 450 The idle speeds up when the bike is in gear. When I start it up the idle is fine. When I click it into gear, still fine. After I ride for a few, the bike is idling fast. I notice it when I try to roll through corners and when I stop and pull in the clutch. I click back into neutral, the idle drops back to normal. It this a throttle position sensor issue and how do I deal with it?

Thanks!

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!) Is your fuel screw set right and do you have the correct pilot in? I assume you did not do the blue wire mod (this affects idling).

You can try to unplug the TPS and see if it makes a difference though I doubt it. I'd also try the blue wire mod as this may solve your issue.

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The "blue wire mod" is a waste of time and does nothing of any real value.

Your problem sounds simply as if your bike is running lean at an idle.

First, check that the hot start cable has free play in it, and operates smoothly, and returns/closes completely. Be sure your carb is clamped into the mounting sleevs correctly. Then, set your idle mixture:

http://www.thumperfaq.com/jetting.htm#PJ

Then use this process to gauge whether you have the right pilot jet:

http://www.thumpertalk.com/forum/showthread.php?t=327405

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I may be too lean on the pilot.

Quick question, when i turn the fuel screw all the way in, should the bike stall? Currently i am running a 42 pilot. When i turn the screw all the way in, the bike does not stall out.

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Hey Gray, I too, found the blue wire mod to be a waste of time but... The Q starts out by saying the bike idle is high when in gear, normal when in neutral.

I agree, a high or hanging idle is a too lean pilot. I'd go up top a 45, see if closing the fuel screw stalls the bike. Then open it to around 2 turns.

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... The Q starts out by saying the bike idle is high when in gear, normal when in neutral.
OK, and I can see you know what the neutral switch does, but if you disconnect the blue wire, the ignition timing would be the same more advanced setting in neutral as it is in gear, which would make it idle fast in neutral as well. Of course, he could then just lower the idle and it would be consistent in/out of gear, but that really only covers up the problem. It should idle normally with the netral switch connected.

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I agree. Mine is fine connected.

Hopefully, he'll do the pilot test and find he needs a larger pilot or that his existing pilot has some debris in it.

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