Well after a several month wait for dyno jet to get a jet kit for my wheeler, I finally got around to installing it with a K&N filter.

After running for several months with the 27" DD's and no alterations there is a noticeable performance gain in going with this set up. Don't get me wrong, my 375 turned the 27's with no problem but after the installation of the jet and filter i wonder how i ever lived with out it.

It has a noticeable improvement in throttle response, dosen't seem to "BOG" down as quickly in the thick stuff, and generally just adds to that seat of your pants thrill.

if anyone is looking into this for there AC buy the jet kits from ROCKY MTN. ATV and save yourself around 20 bucks. there easy to install and IMHO are worth the combined $80 + - i spent for them.

 

I've noticed a slight power difference since getting my 26" DD's (it could however be my imagination). What a great tire for the 375 [img]i/expressions/face-icon-small-smile.gif[/img]. How much fine tuning if any did you have to do. Since I've never played around with changing jets a little info would be a great help. I have been wondering what Blackmagic racing has in store for the 376cc. Right now all their parts seem to be focused at the 300, old 400, 454 and 500. People on different forums and the a few dealers have said the 376 has only slightly less grunt than the old 500, although it would be nice to unleash a few more ponies [img]i/expressions/face-icon-small-happy.gif[/img].

 

Ya, there's always room for more grunt!
I didn't need any fine tuning, the directions were real straight forward and easy to follow. the only thing that i would recommend is that you get yourself a few extra of those screws that hold on the vaccum slide cap because they seemed to strip easily on mine so i had to run into town for some replacements.


But it was real simple to install there is no need to even remove the carb.. just loosen the clamps and carefully spin it side ways.

It would be nice for some more after market parts to be available for this model, but even with out all of the fancy stuff its still a great machine that can do just about anything...

 

Yea, I know what you mean about stripping screws. The screws that hold the oil strainer screen in place gave me trouble. I might look into the dynojet kit. If you have a chance search for this topic by Cowboy:
Auto Tranny Mod-
Minehunter emailed me the diagram; I just haven't got around to doing it or even convincing myself to do it.

 

Are either of you guys running 12 inch wide tires in the rear? I just got my 26x10x12 front and 26x12x12 rear dirt devils. After installing them i noticed they were going to rub on my rear shocks. Did you guys install spacers? and if so what kind??[img]i/expressions/face-icon-small-tongue.gif[/img]

 

No I'm running 10" wide all the way around. With 10's you don't need to run spacers. I think Cat changed the shock location on the 02 ACTs (increase ground clearance) so they require spacers to prevent rubbing when running 12's. Mudcat47537 had some for sale (the last time I knew).

 

Good report on the jet kit/filter! I have an 03 400 which is the same engine and I would like a few more "beans" to turn the 27x10x12 and 27x12x12 Mud Bugs. Don't get me wrong, the machine is pretty good stock, but when she gets hauled down in the thick stuff it could use a wee bit more!

Some pics....

 

Hi, I have an '02 375. I have the stock tires on it and just got a K&N Filter from my dealer last night, but he said AC did not yet offer a jet kit for the machine, so he gave me a 160 to try instead of the 150(stock) jet. He also had me open up the inside of the airbox top. I cut it open basically all the way around the inside lip, it looks like a stock 500 cover now. Anyway, with the increase air flow from the modified air box cover and the K&N filter I installed the larger jet and it fell flat on its face, sputtering on accelleration. I reinstalled the 150 and runs good. Where did you get your jet kits, and what size did you go with after installing the K&N filter? I am not a super tuner and have limitted experience, but I am wondering if AC jets them fat from the factory and maybe the 150 will work just fine??? What do you guys think? Thanks.

 

If they're like any other manufacturer, they are jetted WAY fat from the factory. You could probably go to a couple of sizes smaller jet yet, depending on the elevation you ride at.

 

Topping this one.....curious if anyone else has tried a K&N and jet kit on a 02 375 or 03 400 (375) ?