[Raskul]

trx400ex idles ok but runs rough

Hi I'm new and I just bought a 2000 trx400ex. I cleaned the carb and got it running and it idles fine but if I give it any gas then it starts to die. Could this mean my timing is off? Also it produces a lot of smoke from the exhaust, should I get new piston rings?

 

[Here 2 help]

The carb needs to be cleaned and adjusted. If it idles but won't accelerate, it means is not getting gas mixed with the incoming air and it won't run on all air. Or the smoke issue - if it's blue smoke, its oil - if it's a white smoke that seems to disappear rather than drift, it's gas vaporizing in the muffler - if it's black smoke, it's an over rich condition in the carb.

Check your oil - I have seen a lot of used machines that never had the gas shut off and the crankcase is full of a oil/gas mixture. That will make it run bad, can force it to use oil and is hard on seals.

 

[Raskul]

The spark plug is black on the tip. What does that mean? The smoke is blue. How do i adjust the carb?

 

[Here 2 help]

Black and wet indicates burning oil - blue smoke indicates burning oil

Black and fluffy indicates an over rich fuel mixture

You can't "adjust" the carb (except for idle) without removing the carb and making internal adjustments, like changing jets.

 

[Raskul]

ok i got it running. The timing was off a little bit. Set it at the right position and it runs great.

 

[Here 2 help]

I'm curious - how did you set the timing? The timing is set by the crankshaft and is triggered by the flywheel.

 

[Raskul]

I unscrewed the little bolt on the flywheel cover and turned the motor over till i found the "T" on the flywheel. Then i took the valve cover off and looked at my cam. If the timing were right on (making sure that the flywheel was still showing "T") then the two lines on the sprocket of the cam should have been lined up flat with the cylinder head edge. But my cam was tilting so i took the timing chain tensioner off and wiggled the chain off the cam sprocket. Then once the chain was off i made the two lines flat with the edge of the head and made sure the "T" was still showing and carefully put the chain on the cam making sure not to lose the "T" and not to turn the cam. then once i had it all set i put the tensioner back on (When putting it back on make sure you take the screw out of the top of the tensioner and the get a small flathead screwdriver and turn the screw that is under the external screw so that the tip of the tensioner goes into the tensioner). then put the rest together like it was.