I have a 2002 TRX 250EX which has been running well for the year I have had it. My son said it was running hot and then it died. Will not start now. Cranks over well, and seems to have a strong spark. Carburetor checks out OK, actually cleaner than I expected. Plug wire was pulled out of boot, but that has been repaired. Also tried an aftermarket coil, but spark seems the same with either coil. Is it possible to have a good spark, but the spark timing be off? How do you adjust the spark timing on this engine? I have seen several posts on how to verify spark timing, but none on how to adjust it. Could the problem be with the Stator or Pulse Generator? I still need to do a compression test and check valve gap. But a hand over the intake, a finger over the spark plug hole, and a hand over the exhaust tell me that the valves and piston are doing their job reasonably. Oil consumption has been very little, but it was low when the problems started.

What is the outcome of increasing the sprocket size on the rear by one tooth? Little help here.

And is it recommended?

What is the outcome of increasing the sprocket size on the rear by one tooth? Little help here.

And is it recommended?

Just bought a 2006 250ex yesterday for $1k with a rear end leak.

Now at first I thought it would be as simple as pulling the wheel and hub off, and ramming an axle seal on there. Now I’m starting to think the axle area isn’t supposed to be filled with oil at all and the differential is actually leaking into the axle which is in turn leaking out.

I’m looking for advice, and guidance on how to do this. If anyone knows which parts I should buy, where I can download a service manual, that would be great to have as well. Thanks.

Just bought a 2006 250ex yesterday for $1k with a rear end leak.

Now at first I thought it would be as simple as pulling the wheel and hub off, and ramming an axle seal on there. Now I’m starting to think the axle area isn’t supposed to be filled with oil at all and the differential is actually leaking into the axle which is in turn leaking out.

I’m looking for advice, and guidance on how to do this. If anyone knows which parts I should buy, where I can download a service manual, that would be great to have as well. Thanks.

Hey Guys,

I have a Rigid Industries LED light bar that I am trying to install onto my 400ex for some night riding.

I have been trying to research what the stock stator outputs as far as power. The LED light bar (Part Number: 110312) Uses 65W (about 4.7 Amps).

Will the stock stator be able to hold up to this amount of power consumption? Or will I need to purchase a high output stator?

Thanks,
Jake

Ok ive tried to do as much trouble shooting as I can, but im beyond my level of ability. The bike will crank and run most of the time….it sounds like it has a slight miss at idle but nothing that raises by brow. When the bike is cold it runs and accelerates GREAT! When it gets warm to run good on the low end and top end RPM but if I have it as a medium RPM and nail it, it back fires and stutters until the RPM raises. When I stop the bike and let it idle for approx 20 secs and get back on it after idling it runs great for another 20 seconds or so then back to spitting and backfiring. When at an idle and warm I can turn the choke completely on and it doesnt affect the RPM at all. Anyone have any idea where I can go from here.

2008 400ex hot cams gull exhaust KN filter without lid on box air screw 3.5 turns out.

Ok ive tried to do as much trouble shooting as I can, but im beyond my level of ability. The bike will crank and run most of the time….it sounds like it has a slight miss at idle but nothing that raises by brow. When the bike is cold it runs and accelerates GREAT! When it gets warm to run good on the low end and top end RPM but if I have it as a medium RPM and nail it, it back fires and stutters until the RPM raises. When I stop the bike and let it idle for approx 20 secs and get back on it after idling it runs great for another 20 seconds or so then back to spitting and backfiring. When at an idle and warm I can turn the choke completely on and it doesnt affect the RPM at all. Anyone have any idea where I can go from here.

2008 400ex hot cams gull exhaust KN filter without lid on box air screw 3.5 turns out.

I put the starter from my 87 350d on my 93 300fw. It spins but it’s not trying to start the motor. I was thinking it may be spinning backwards is that possible?and if so how can I fix it?

Are there any other fluids to check other than brakes, engine oil and rear end? If so, where do I find them!
Thanks