TTR90 will not idle, need help!!!!!!!!!!

[ColdChillin]

Guys I got my son a used '05 TTR90. It was purchased new in August '05 and still looks brand new. We traded his PW50 in on it, so this is a nice step up for him and he loves the little 90. He's been wanting one for almost a year now, and I couldn't pass up the deal the guy at the dealership offered me.

I've had a little experience with a TTR125 that my wife had for a short time. Great little bike, but very cold natured. Still though, it'd crank fine and once you ran it with the choke on for a while and warmed it up it'd idle just fine. The 90 seems as if something is out of whack and hopefully one of you guys can help me. I'll describe the quirks as best I can.

Ok the first thing is when it's dead cold and hasn't been ran, I choke it, hit the starter and it fires up instantly and revs a bit high then dies. This happens in a span of like4 to 5 seconds, it doesn't run long. Usually it will fire back up with the choke on and run. It seems to run good when you initially crank it but as the seconds tick by you can hear the rpms diminish and the bike will run a little rougher then eventually die again. If you keep tolerating this and keep restarting it, which seems to get harder and harder each time you have to refire it, it will eventually run ok.

But if you lean the bike over to the right it runs better, revs much higher at idle??? That doesn't seem right to me. Also I really feel that when it is running with the choke on that the rpms are too high. But with the bike warmed up and choke off the idle speed is set as low as I can set it. The idle adjustment is almost all the way in though. I also set the pilot screw per the manual at 1 and 3/4 turns out. I tried other settings and this one seemed like the best.

The little bike runs strong and revs good in all the gears with nary a miss, and once you finally get through all the cranking and warming up it's all good. But trust me when I say that it is a big headache for me to get it running, then keep it running until it does warm up. My 6 year old son doesn't stand a chance at keeping it running, and that bums me out because that little PW50 was flawless when it came to cranking, idling and whatnot.

Please help, I do not want to take this bike back to the dealer to be worked on. We've got a trip planned next weekend and I'm taking his bike if we can get it sorted out. Thanks.............

[ovrrdrive]

Sounds like its starving for gas to me...

Give the carb a good taking apart and cleaning paying particular attention to the jets and the holes they come out of and see if that helps.

If it still starves, check the petcock to make sure it's flowing freely.

I'd place bets on a dirty carb, especially the pilot jet. Many of these bikes get bought, run, then put up with gas still in the carb. This then turns to a gummy mess and clogs up the carb while it sits as the kids grow into some other hobby. Then the bike gets sold and the new owner has to figure out what happened...

Try it and see.

[ColdChillin]

You're probably right. The bike was purchased in August of last year and appears to have only a few hours on it. So it more than likely is gummed up a bit. I put a few ounces of seafoam in there but it hasn't helped. I've been real busy lately and have actually had very little leisure time, so I'm ready to get this little bike back in top shape. With all that said, I spoke to the dealership earlier and told them the bike wasn't running right. They want me to bring it in first thing in the morning so they can check it out.

I really didn't want to waste a bunch of my Saturday at the dealership, but they assured me they could get me in and out in an hour or less. So I guess I'll take them up on it. We'll see how it goes. They really can't make it any worse as far as the idling goes. Everywhere else the thing runs like a top.

I'll post their findings asap.

[PumpkinHumper]

I am betting on a plugged pilot jet. That pilot jet is so small on these bikes. It gets plugged up super easy. Its super easy to take out and clean.

1. Take the LH Tank shroud off.

2. Turn the gas off.

3. Lay the bike over on its RH side.

4. Take the 4 philips screws out of the bottom of the float bowl and remove the bowl.

5. There are 2 jets in the bottom. One on the center and another to the side. The center one is the main and the other one with the slotted head is the pilot. remove the pilot jet.

6. Take a piece of wire, A strand from a wire brush will work great, and run it thru the pilot jet. sometimes you can see light thru the jet but there is still crap in there. Run that wire thru a few times. You dont want to scrape the hole bigger mind you just get the junk outta there. Carb cleaner usualy aint enough to get it out. Use wire.

7. Put the pilot jet back in and reinstall the float bowl.

Warning. When the bike is on its side like this the float pin can come out and the float / needle will fall to the ground. Keep an eye on that. You need those parts. Bike wont run too well without them.

That should do it.

I just did my kids bike last week. It was starting and stalling like yours. It would cough and weeze till it was finially warmed up. Thats all the pilot jet. Not getting enough gas.

You know where the idle adjustment is right? Its on the rh side of the carb up against the motor. Its a little knurled knob. You have to twist your hand a little to get at it.

Good luck.

[ColdChillin]

You guys were right. Clogged pilot jet, due to sitting up. The thing runs and cranks like it's supposed to now. It seems to be a great little bike, and actually runs a bit stronger than what I figured it would. It's a great bike for my son, he's stoked about it.

Now you can just bump the started and she lights off with nary a hitch. It actually cranks much better than my WR450 did, and the 125LE that my wife had. ?