Leaf, if your headpipe is getting orange, under fairly normal, even hard riding, ther is someting fishy going on. Your exhaust temp is too high, wich means that more than likely, you are right and you are running too lean. I have never heard of a 4 stroke quad getting that hot. Another possibility is that the exhaust system is plugged. I had the exhaust get plugged in a truck of mine several years ago, and it had the same symptoms(orange to red exhaust manifolds). Either way I would change something soon. If the exhaust is getting that hot, there will be damage to the engine sooner or later. Most likely burnt valves or even a cooked piston.

 

I had an old chevy cavalier when I was in high school that everytime the manifold developed a crack around the spot where the 4 pipes merged it would cause the computer to run lean(oxygen sensor would go nuts) and the headers would glow around the cylinder head. Check the mixture and then look for an exhaust leak or a plugged exhaust system. it only stands to reason that a high water temp will result from a really hot burning engine. If it is running that hot a stuck ring or piston problem is on the horizon.

 

I think it's normal for the pipe to get a little glow on long road runs. I know my 300 & buds 500 Cat both will glow a little on extended high speed runs. Cats only use single layer exhaust pipes unlike some other manufacturers like Honda that use double thickness exhaust.

 

Scootdog706
I checked my exhaust pipe and muffler and all is clear. Thanks

Dakotart
How would I check the mixture? Can I adjust it without changing jets?

Does anyone know what the thermostat temp. setting is? and what the normal engine temperature should be?[img]i/expressions/face-icon-small-confused.gif[/img]

 

To check the mixture just pull the spark plug. It should have a nice straw or light brown color to it. Black and you're too rich. White or grey and you're too lean. No way to change the mixture without changing jets. At least it's that way on the 2000 models. I don't know the elevation where you live, but the standard jet is a 150.

 

Minehunter covered it right on.

Dakota R/T

 

The opening temperature for the thermostat is (119.3 - 124 degreesF) this is when it should start to open. I know that on all of the Cats that I have seen the headpipe will glow when used hard, even my current 500 that is just a little rich. I have seen this discussed before and was told that the headpipes on the Cats are stainless and that they will heat up and glow before regular steel will. I don't know this for sure but this is what I have heard in the past. Also when we go to pulls allmost all of the quads there will have a bright orange glow down there after a pull. I have quit worrying about it, as long as the temp light doesn't come on I see no problem.

As far as wiring the fan on the 375 to run all the time I see no reason why you couldn't. I don't see any need to do so, I hate the noise of the fan running all the time. You also get into blowing fuses at water crossings and reducing the life of the fan motor. The reason why it comes on and goes off so much is because it has such a close on & off temp. It comes on at 320 and goes off at 284 F.

 

I had one problem with my macine getting hot Icleaned up the radiator cover and everytime I got it in deep mud or water it only takes a minute. keep buying Artic Cat.