Idle high after riding fast

blaster003

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May 13, 2014
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I have a 2003 yamaha blaster and if you get in top speed in any gear it idles high when you stop until you let off the clutch and it has fmf 280 jet and fresh top end it also sounds like hammers in top end when idling high what could this be
 
Running it lean due to an air leak after it warms up. I would leak test it asap. Hammering is detonated. Your jetting maybe way off due to an air leak. Fix it before you ride it again. You may have already damaged your piston. Pull your pipe and look at it. It has to come off regardless for the leak test.
 
The hammering noise is only when you let off the gas at full throttle it did the same thing before I rebuilt the top end before could this be the octane I have 93 but it had been sitting for about 2 months could this be the effect
 
The hammering noise is only when you let off the gas at full throttle it did the same thing before I rebuilt the top end before could this be the octane I have 93 but it had been sitting for about 2 months could this be the effect


drain that old fuel, put fresh 93 in it,
that should deter detonation/knock up to around 165-ish psi. compression
 
List full jetting as well. A 280 sounds about right, but if you're running an erroneously sized pilot and needle, you'll get knock when you let off.

That 93 is probably about as effective as 75 octane by now. Get rid of it.

FWIW, I always like to jet pretty rich on pilot and screw. I always touch the throttle when I let off the clutch to keep premix and air coming through after I've been at high rpm.
 
Would the electronic switch on the brake lock have anything to do with it idling high after high rpms and I have the idle adjusted on the higher side because if it's adjusted where it sounds the best it will idle for about 300 then drop down and die what could this be and the tors is removed
 
Not to thread jack, but how long does it take for gas to go bad? I usually use mine up within a few weeks, but didn't realize it could go bad in the matter of a month or two.
 
it's not tors or park brake related
hanging idle is usually a lean condition.
try adjusting the airscrew in another 1/4 - 1/2 turn
 
Not to thread jack, but how long does it take for gas to go bad? I usually use mine up within a few weeks, but didn't realize it could go bad in the matter of a month or two.
If there's ethanol in it (which there is in everything, even if they say its not) it will soak up moisture like a sponge. People think its better for moisture because you put alcohol in if there's water in your gas, but that's cause it locks onto it and carries it through. I don't keep any thing for over a month. I learned that when I bought a brand new $500 stihl chainsaw and it was ruined after 2 years
 
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Don't pull it out all the way just mess with it a lil at a time and see if it corrects the problem
 
Maybe someone with more knowledge will chip in, but would it be possible that there is a fuel build up happening somewhere, maybe unburnt fuel in the pipe that circulating back in