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  #1  
Old 11-08-2004, 11:23 AM
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Question 2002 ttr90 won't idle???

I just bought a 2002 ttr 90 in great cond. but, it won't remain running under 2500rpm's unless the choke is on? with the choke on It will idle and run almost perfectly through all 3 gears??
I removed the carb, disassembled and cleaned all the jets, float and needle valve, and an orifice i could get cleaner into, ( it wasn't the least bit dirty) I put it back togeather and it is 100% the same?????????????? the choke is working correctly There is also an electric sensor on the carb either temp or knock sensor but not sure.

Any idea's
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Old 11-08-2004, 04:57 PM
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Default Re: 2002 ttr90 won't idle???

ist there still an idle screw in the carb? and is it tuned
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Old 11-08-2004, 07:29 PM
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Default Re: 2002 ttr90 won't idle???

My friends kid has the same bike and I swapped carbs and it ran perfect, So I have confirmed a carb problem,
I adjusted the rich adj screw the same as the good carb (1 1/2 turns from fully seated) the idle is set for the choke on appro 900rpm's

Question:
The adj screw on the bottom of the bowl near the drain hose- what does this adjust???
it was when I got the bike and is now fully INSERTED CLOCKWISE and bottomed out

Thanks,

Fran
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Old 11-08-2004, 07:50 PM
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Default Re: 2002 ttr90 won't idle???

that is the fuel screw, it is similar to the Air screw on a two stroke, only completely different. (dont you hate that when people say that)

basically, it meters the amount of fuel entering the carb at small openings. to let more fuel in, (richer) turn it out- to let less in, (leaner) turn it in. in your case, when you have to have the choke on it means you need to richen the air/fuel mix by turning the screw out. i dont remember how far we had ours out but just fiddle with it until it runs right.

unless, of course, i just described the "rich adj screw" you mentioned on the good carb- i didn't really fiddle with my sister's carb too much to get to know it really well :

Rob
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Old 11-08-2004, 09:42 PM
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Default Re: 2002 ttr90 won't idle???

when you get it running take it for a ride and get it up to full throttle then hit the kill switch do not let it idle down just kill it then take the plug out and check the color. If the coler is black then you are too rich if it is more light grey i beleive it is to lean it should be dark grey. If it is to rich this could be the main if it is to lean it could be the same. Has there been any mods put on latily. There should be a screw on the side about 3/4 way up with a spring on it that is the air screw. Factory the main jet in that bike was 90 and the pilot is a 12.5 according to my diagram. If you need it I can email you a copy of the breakdown of the carb. in detail. good luck
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Old 11-10-2004, 06:08 PM
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Default Re: 2002 ttr90 won't idle???

Thanks to all who replied,
I pulled the jet that controls the idle-1/8 throttle (?? idle jet)and brought it to a shop they looked at it with a magnifying glass and it was approx 50% clogged, they cleaned it and: waaa-laaa good as new.
I got a great deal on the bike, $625 for a 2002 and it still has the little rubber tangs on the tires.
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Old 11-10-2004, 06:17 PM
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Default Re: 2002 ttr90 won't idle???

Very good deal for that bike. I'm glad you got it running. I've been watching this post to find the culprit.
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Old 11-10-2004, 07:01 PM
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Default Re: 2002 ttr90 won't idle???

Quote:
Originally posted by FULL-THROTTLE
Thanks to all who replied,
I pulled the jet that controls the idle-1/8 throttle (?? idle jet)and brought it to a shop they looked at it with a magnifying glass and it was approx 50% clogged, they cleaned it and: waaa-laaa good as new.
That is the pilot jet. It works in conjunction with the fuel screw to control the mixture from 0 to around 1/8 throttle. Like Rob said, the fuel screw is used to fine tune the mixture and will richen the mixture when turned counter clockwise while leaning the mixture when turned clockwise. With your fuel screw bottomed out and the engine running fine that would signal to me that your pilot is too rich. You could probably drop a size or two and dial in the fuel screw for better off-idle response and more low end power.
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