Any suggestions on improving power. I only have 120 miles so maybe power will improve with break-in, but I found myself wishing for more power. Are there any mods that will make a noticable difference? Or should I consider spending the money trading up for a 650. Maybe the stock tires weren't hooking up in the mud? I should probably ride in dry conditions before I make a judgement.....only done one day of hard trail riding...Thanks for any input.

 

Well Not in this order but exaust kit,maybe a HMF if you don't mind the loud and proud sound of power, and then new jets and filter go with the pipe, try to go with a synthetic oil to improve lubercation and lower friction to improve more HP then use your imagination. PLus you said that you wanted a tire for mud, but remember bigger tires mean Less Hp but more ground speed and having to recalibrate your tranny if it's a Auto and speedo. Gook luck

 

I have an 03 400I auto and I was dissapointed with the speed and lack of power. I have not done any mods yet and was worried that this bike was just a big turtle!! Anyway, I recently went to Wva and currently have 269 miles on mine now and it is running great! I was told that you have to get between 300 to 500 miles on the 400 auto before it really performs and so far that seems to be the case! I guess it needs a long break-in period! Before I would do any mods, I would swap out the tires if you have the dunlop 25x11x12 rears and replace them with 25x10x12 tires! I think a skinnier tire in the rear, maybe even a 25x9x12 tire would really help with speed and torque for the auto. Don't give up yet because I took my cat threw alot of mud and water up to the tank more than once and the front-end floated and all 4 tires pulled the cat to the other side!! I have had no problems with water in the belt housing. I am very impressed with the atv. I rode with two 450 formans and they are great bikes but they beat the hell out of ya and the cat has a much, much smoother ride!!! The worst thing on the 03 cat is the tires and they need changed. Hope this helps!

 

I have 03 400 4x4 too..I am in need to replace my tires also. They're getting pretty bald. I use the 4 wheeler for my 1/4 mile drive way for snow removal with the plow on, plus working my garden dragging off the weeds. It's just an awsome machine!!

However..I can't decide what kind of tires I want. I noticed that the original tires on rear are Dunlop KT127B 25X11-12 and I found them on line for 96 bucks each!! Ouch!! There's another set of tires that are ITP MUD LITES that are 25X10-12 for 56 bucks each.

What I'm trying to understand why it's more expensive for dunlop tires than ITP Mud lites tires. If the mud lites are supposed to be better, lighter and great for mud/snow, why isn't it more costly than the dunlop?

Are dunlop better?

I was thinking about going for 25X10-12 instead of 25X11-12 after what I read the tires should be lighter for more speed and power..would the mud lite tires be better for all the work for snow removal and dragging for weeds?

What do you think?
Please reply ASAP want to order the tires today!
Thanks in advance!
mountaindew

 

ok Guys here is what I've done to my 03 400. I got the HMF.dynojet kit and K&N filter plus an EPI Clutch Kit.

these mods WILL wake up a sleeping Lion if you know what I mean. But there is Nothing to make up for CC's.


tires Make a Difference I Started with the Highlifter outlaw Radials on mine I NEVER ran the dunlops I bought it new with the mud tires on it. If I was buying another mud tire it would be Mudlights. The Radials are WAYYYYYY toooo Heavy. I now have a set of Carlisle Badlands on and they get me everywhere I want to go except the REALLY deep Mud Holes. the power is good and they ride smooth as far as the weight they weigh less mounted up on steel wheels than the Outlaws do by theirself.

For the Money the 400's are an awsome bike I can go where others just watch but.... you do have to give it time to break in (300 to 500 miles)and nothing makes up for cc's

 

Oooby, does HMF make a pipe especially for the AC400. If so, I can't find it, where did you get it? Thanks

 

No but the 03 500 pipe will fit Right on the 03 400 with no mods [img]i/expressions/face-icon-small-smile.gif[/img]

 

mtdew, I have the 04 400 manual and i added 26x10x12's to the front and 26x12x12's to he back, i also plow alot and noticed that they really helped with the snow, I am not usually running for speed so i didnt care if i lost 1 -5 mph, but in the snow and mud i would have them over my stock dunlops any day.

 

I bought my wife a 2002 375. I am pretty sure it is the same engine as the later model 400's. It had 308 miles on it when we got it. It now has 425. It seemed to be getting stonger, but was still sluggish on take off. I had an EPI clutch kit installed and it is like a different bike. Strong takeoff and midrange now, my wife loves it. Also put a set of highlifter lite steel wheels with titan 489 XT's on it. For us this works well.