ATV Florida Forum

My son has a TTR-90.  He rode the first time for about 1 1/2hr no problems.  Then the second time at the track he started sputtering going up hills.  Took the carburetor out, cleaned it put it all back together, check the plug (it was black) and now it starts for about 2 seconds and quits. Won't start again. Any ideas out there?  Thanks.

Is it brand new?

No it is 2001.  just bought it 2 -3 weeks ago.  Never had a problem till the track the second time. He has rode it around the yard no problems.  The inside of the carb was lined with deposits.  I cleaned everything and still nothing.   It has two electrical contacts on it, what would they be? 

Is the air filter clean? When you bought it was it sitting for a while? Is it getting fuel? Is it getting spark?

It is getting spark to the plug, have not checked the other end of the plug.  I don't know how long it was sitting for.  Air filter is clean no gas smell no oil no tears or anything else.  Even took it off and tried with no filter and nothing again.  I checked the floats again to make sure they are still moving, Everything seems to be good on the carb now.  Still have no idea what the two wires going to the top of the carb is.

Post some pictures if you have a digital camera.

news. Watch where you buy gas. My car just started acting up and we found out it is the ethanol in Hess gas. Since switching gas stations and avoiding hess the car has been running fine but on hess gas it sputters and acts like crap.

can't attach pics

sent you pics in an e-mail trx450r

I don't know what they are maybe someone else does. Do you know Turboderf?

Click to make pic bigger

   did you check the pilot and the main jets ? make sure they'r not clogged   put in a new plug  .  old one may be fouled!

 It's a heater that keeps the venturi area from icing up . Shouldn't be an issue since it doesn't run long enough to ice up . I would like to think that he checked the slide needle and the vent hoses while cleaning it . It might have a bad/or improper plug and/or cap, which could result in a weak ignition causing the bike to break up under load ( hills ) and foul ( black ) the plug over time . This might be worth checking, provided the fuel, exhaust, compresion, and air filter are ok .

As far as the jets they are clean.  The throttle needle seems to be working correctly, goes up and down with a turn of the throttle.  The fuel bowl is filling up becuase I can keep getting gas out of the drain.  When it started to bog down he was running it for about 1/2hr.  I planned on changing the plug going.  Why is it that it idled fine but now it runs for about 2 secs then dies on the first kick after reinstalling the carb then nevers turns over again, that is what is driving me nuts.  The floats seem to be working fine, the fuel flows good, once I change the plug if that don't work then I'm lost.  Thanks again for all the help.

black plug means rich...

If it run for a few second after you let it sit, check the reeds. A broken reed will let it flood right after start up.

Like turboderf posted

I would make sure you have the correct spark plug. NOT a slight variation of the stock plug. Get the exact part #, becasue if you get one with the wrong resistance you will have the exact problem you are speaking of. Been there done that. If the correct plug doesn't fix the problem buy a new factory spark plug boot. One of those 2 things should fix it. Good Luck.

I thought the electrical lines were the TPS (throttle positioning system).

If those are shorting out, cut or not connected, I could see it messing up and shutting the bike off.

a 2 stroke should never have any kind of tps or anything like that, if the plug is black you are running it pig rich and that cold be part of your problem... the plugs should be a toasty brown, grey means lean/overheated, black means rich/fouled. it sounds like you need to re jet. if it has reeds you need to consider that to be a possible issue. if the ignition system is a point/ condenser system than than chances are that is your problem right there. a bad condensers core will get play in it as the rubber around it in the condenser gets hot. when you have bad condensers your spark is unpredictable and impossible to jet correctly. if it has a tuned pipe and that leeks that will also throw the jetting off and make it impossible to jet, same thing goes for if it has no compresion... this bike a 2 stroke correct? i don't know anything about what exactly is on the bike so i just gave you a good bit of basic knowledge that should help IF its a 2 stroke...

O and btw tps stand for throttle position sensor, and iv never heard of one being on anything other than a fuel injected bike. the propose of a tps is so that the ecm knows the throttle position compared to rpm to deliver the proper amount of fuel based off off of an air fuel reading from an 02 sensor, the tps is part of a full system that works together for Edi moters, iv never heard of one on a carb?

iof this bike is a 4 stroke i just waisted my time typing lol

It is a 4 stroke. My YFZ has a TPS and if it becomes disconnected, it wont run. Not fuel injected.

this is a 4-stroke and I tried it again today just for S&*t's and giggles and it did run....very badly, but it would run.  I haven't made it to the store yet to get a new plug but I think it might be it.  It's a good thing this thing is not a horse or it would be costinig me a bullet too.  Lol. >:(

o yea thats right, the tps on the yfz is for reference for spark or somethign prety useless like that, it can be goten rid of but in stock trim you are right it wont run without it, sory for not thinking of that...

Got a new plug today.  I tworked better put still putted out out after a while.  Ordered a new "heater element thingy" that has to be it, if not off to the shop with it.

Replace the spak plug boot and put in another new plug at the same time. Try this before you take it to the shop.

this is a quit simple idea, are you sure your idle is set correctly adjust the screw on the bottom of the carb i know if i tighten mine too much it will start for about a second then die sometimes backfires too. probably not it but worth checking the very simplest things first. i onced stripped my bike down and checked every  wire becasue the new battery i had bought too replace the old one was a dud too... missed a race because of that dumb sh!t, so worth it too check that out...good luck.

jake

When I took the carb apart both of the jets were snug.  I was told that, that was wrong they should not be in all the way so I backed them out half a turn.  Try putting them back the way they were.  I might try the boot if it is not too much.

The main jet and the pilot jet that are inside the bowl need to be tight. If you loosened them take it back a part. While the bowl is off make take out both jets and make sure all of the holes are clean. then put them back in and tighten them back down. The only thing that shouldn't be all the way tight is the air/fuel mixture screw and it is outside the bowl. eveything inside the bowl needs to be tight. Whoever told you to loosen them, stop taking their advice.

I did that earlier today (tighten up the jets).  It still runs like S*&T.  I'm about 2 secs away from running to a shop.  The thing that realy makes me mad is now' I'm going to pay like $100-$300 to find out it was something stupid that I overlooked.      >:( >:( >:( >:(

here is an idea. take the mixture screw and screw it in until it stops. do not over tighten. then unsrew it 2-1/2 turns out. that should give you a good starting point to see if it's a air/fuel problem. If that does not correct it I would see if there is something like a pick up coil that can be replaced. I am not familiar with the TTR series, but it sound like some familiar issues I have dealt with before.

good call, you need to get a feel for tuning that tho, not hard at all but for someone who loosened up his main jet it may be above your head lol, im jk. you need to play with the air fuel, it can make a diference.