over heating problem?

[j_cyrus3]

My bike is just shuttin off after I ride it real hard for about 20-30 min. It will start back once it is cooled down though. I ride XC, and I really need it to run for more than 20 or 30 minutes at a time :\ anyways, i think it's the coil but im not really sure, anyone else got any ideas? My fan is wired to run all the time, and it still runs, i don't think that would have anything to do with it though really. It's not getting REALLY hot, but it's warm. Any info please let me know, thanks.

[DirtDevilBT]

? bump? good luck with that wish I could help, sounds like your on the right track something is getting hot or grounding out, not the motor tho

what octane fuel are you running? is it a low octane?

[Punk'd]

Buy some air scoops and some engine ice coolant.

[d3ktrix]

Originally posted by Punk'd
Buy some air scoops and some engine ice coolant.

If the engine is over heating it has an internal problem. Just masking the problem by forcing more air over the engine will not stop the problem; it will just cover it up until something fails.

Cooling the engine with air scoops will not stop a friction problem due to an engine starving of oil or running lean from bad jetting. The engine is still self destructing inside, you just can't tell anymore because you are pushing the heat away with more air.

The proper use for air scoops is to bring the engine below NORMAL operating temps for extended engine life. Or running in hot ambient conditions.


Originally posted by j_cyrus3
My bike is just shuttin off after I ride it real hard for about 20-30 min. It will start back once it is cooled down though. I ride XC, and I really need it to run for more than 20 or 30 minutes at a time :\ anyways, i think it's the coil but im not really sure, anyone else got any ideas? My fan is wired to run all the time, and it still runs, i don't think that would have anything to do with it though really. It's not getting REALLY hot, but it's warm. Any info please let me know, thanks.


Is your water circulating? Stuck thermostat maybe?

[exracer131]

it really sounds like an electrical componet getting hot and the ohms going up causing the componet not to work. the coil would be the first thing i would check, just be sure you check it before you ride and when the engine shuts off. at any time did the radiator boil over???? if not the cooling system is working fine. if the oil is getting hot enough to cause the engine to lock up then the cooling system is not working right and sould boil over if the radiator is full of coolant.

[j_cyrus3]

Originally posted by MixMasterMike
what octane fuel are you running? is it a low octane?



93 octane

[j_cyrus3]

Originally posted by d3ktrix
If the engine is over heating it has an internal problem. Just masking the problem by forcing more air over the engine will not stop the problem; it will just cover it up until something fails.

Cooling the engine with air scoops will not stop a friction problem due to an engine starving of oil or running lean from bad jetting. The engine is still self destructing inside, you just can't tell anymore because you are pushing the heat away with more air.

The proper use for air scoops is to bring the engine below NORMAL operating temps for extended engine life. Or running in hot ambient conditions.




Is your water circulating? Stuck thermostat maybe?



No overflowing coolant, no nothing. It runs great, it gets hot like it normally does, but it just shuts off now. I don't know what the hells wrong with it, i ordered a coil, maybe that will fix it.

we had a similar problem, turned out to be that i had gotten water down in the black box on the handle bars and it was building up resistance, we cut the wires and just hard wired most of the wiring to solve the problem, and prevent it from happening again

[marniee62]

look at the vent hose on the gas tank it might have mud in it if you race xc.

[xc400ex]

Hey check this out, if grey installed a fuel filter on your 4 wheeler this is probably the problem, if there isnt a fuel filter nevermind then. Possible the fuel filter is 90% clogged only letting a little fuel flow into the carb at once, being said after you ride it 20 to 30 minutes you finally use more fuel up than it can flow through. You shut it off it fills the carburetor back up with fuel and you can ride it again till it empties. Happened to me before, next time it shuts off, take a flatblade screwdriver and loosen the drain on the bottom of the carb see if any gas comes out, it should if not theres a problem.
Also the 450r's have very crappy spark plug caps, I've had issues with mine, that would be my guess if it did happen to be electrical but I'm betting its not, unless its a loose wire somewhere.
When my valves start tightening up and needing adjusting my 450r will run great for 10 to 15 minutes until it reaches full operating temps, then it doesnt run the best, but its usually alright until it dies then the days over with, possibility too.

[DirtDevilBT]

Originally posted by xc400ex
Hey check this out, if grey installed a fuel filter on your 4 wheeler this is probably the problem, if there isnt a fuel filter nevermind then. Possible the fuel filter is 90% clogged only letting a little fuel flow into the carb at once, being said after you ride it 20 to 30 minutes you finally use more fuel up than it can flow through. You shut it off it fills the carburetor back up with fuel and you can ride it again till it empties. Happened to me before, next time it shuts off, take a flatblade screwdriver and loosen the drain on the bottom of the carb see if any gas comes out, it should if not theres a problem.
Also the 450r's have very crappy spark plug caps, I've had issues with mine, that would be my guess if it did happen to be electrical but I'm betting its not, unless its a loose wire somewhere.
When my valves start tightening up and needing adjusting my 450r will run great for 10 to 15 minutes until it reaches full operating temps, then it doesnt run the best, but its usually alright until it dies then the days over with, possibility too.

Good idea, maybe this or something having to do with the floats? But should have thought about that.

[j_cyrus3]

Josh: Brandon Cooper told me that Dustin had to take his aftermarket rev box off because his was doing the same thing. Im gonna try the carb thing today, see if any fuel leaks out. Ill have another update by the end of the day.

[j_cyrus3]

ok, i just tried that with the carb, plenty of fuel came out...What next? :\

[xc400ex]

What kind of box do you have on it? I got an extra stock one if you want to try it out, if you dont have yours.

[xc400ex]

So I take it the coil didnt help anything? I went riding with grey and n randolph and I heard Nathan say that the thing wouldnt run when grey had it, so this has been a problem for a while.

[j_cyrus3]

still no coil, im waiting on it. the problem nathan was talking about was the idling thing i'd say. the cord was messed up and it wouldn't idle, but i got it fixed, it runs like a champ no jetting problems. ill try the coil and if it doesn't fix it i might come pick up that stock box and see if that fixes it, if it does ill buy it off of you. that sound good?

[j_cyrus3]

oh yeah josh, do you have a 13t sprocket layin around i could buy? i put a 14 on it and i know that will be way too tall for the woods.

[xc400ex]

yeah I've got 4 or 5 laying around, I dont remember how good shape they are but I'll check it out,sounds good to me

[j_cyrus3]

Got it fixed, if anyone was wondering it was the coil. Thanks for all the replies and help guys.

[DieselBoy]

COIL EH? damn what a relief that must have been!