I recently got my 2003 400 i automatic quad and so far I love the machine, I just put on some titans and man those tires work pretty good. But when I get into a mud hole and have to work the engine for any length of time it starts to sputter (this was before the new tires also, I have about 220 miles) my dealer told me that it is a rev limiter but for some reason I dont think so cause when it does it the engine isnt always reved out. But if it is a limiter can this damn thing be bypassed?? Also does anyone know what kind of oil filter to use on this machine besides the one from Cat cause they want $14.00 for a filter!! And to make everyone in the Cat forum happy I had to pull out a 660 grizzly last night, he was stuck in a hole that I got out of under my own steam and a bit of work. But in his defense he pulled me out a bit earlier. Thanks for any help people.

 

hey doober
i got an stp filter at auto zone for my 2002 400
not sure of the size off hand. something like smp1
i'll go look it up
pie 1

 

See this threadthread

 

what should I jet this to, I am not sure what I have in there so it will be difficult for anyone to really answer, but if I cut out 2 baffles from my muffler, I am at 1-3000 ft roughly. I havent done anything to this machine so it will be a stock size jet. I just talked to my dealer today and he said that the muffler trick makes sense and should cure it and it will not void warranty at all. Again thanks for any help.

 

Jets are cheap.....I would try a 148 and put the fuel screw at 2 turns out instead of the stock 2.5......this will be a slight change without going dangerously lean.

 

The dealer here will let me try the jets for nothing, so it doesnt matter what I try, I just dont want to melt down my machine so I want to get something that is good for me. Cause I am going to do the muffler mod, this sputtering thing is annoying, it is causing me grief, things are outmudding me that shouldnt be able to, and tha tisnt good . Again people here have been great and thanks for any help that you can give.

 

so how exactly do you go about this muffler mod, , I looked at some pictures of catkrazy's but dont really know what to do, what end of the muffler do I cut off, then I pull out the inner tube??, and cut it in half?? Or just take a couple inches off?? Then slide the inner tube back in and weld the muffler back together?? Is that all there is to it? Thanks for any help.

 

Doober- Both ends have to be cut off because the inner tube is tack welded at both ends to the outer tube. I cut my inner tube in half and it worked great.

 

ODB, and so i (and doober) understand... Cut both caps off. Cut tack welds holding inner. Slide out inner. The inner can be cut in half then tack welded back in the outer. Put caps back on.

One more question? Is there a preffered end to chop in half on the inner? IE: spout or pipe end, then weld that back to where it was.

Mine has a long 1" pipe going down the middle with lots of tiny holes in it. Which btw are clogged solid. I think ill cut mine up after you reply :]

 

Good question vewdew, I never thought of that (about what end to cut off) so after that just rejet, and turn the fuel screw back and look out here I come. Also my guess is it will be slightly louder?