I have a 2004 Yamaha BIG BEAR 400 4x4 with 28 SWAMP WITCHES on factory rims. Sometimes when im in a mud hole and try to back out it seems like it dont have enough power and then when locked in 4x4 and in a hole sometimes it seems like it dont have enough power to get out...kinda like i need to downshift but im in first. sometimes its fine and dont have any problem but then sometimes it happens. is there any advice on what i can do to maybe fix this problem. I've checked the gear im in, checked the gas, checked the axles, checked everything i know to check. but im kinda scared about putting any gas over 87 octane. ive put seafoam (latest) lucas fuel treatment, im using fully synthetic oil and using lucas gear oil in all the axles. so can someone help me out with this problem so i can continue walking all around these other guys. gotta love the low end torque that it has when it aint messing up cuz it dont spin the tires over in the hole it just kinda walks anywhere it needs to go. i dont do any serious deep mud nothing over the racks, but what i do hit im glad it does how it does!!

 

those are pretty large tires for a 400 in mud if you ask me, but maybe a clutch kit or some shims would help. Thats what im going to do on mine.

 

28" tires on a 400!

you'll need more then a clutch kit-

buy a bigger bike!

 

you have got WAY too much tire for that 400 to turn!!!

Do yourself, your ATV, and your wallet a huge favor and drop down to a 26" tire...Mudlites are good, as are 589s, and they won't rob so much of your low end.

The other choice is to hot rod the hell out of that mid-size 400, but you will spend a LOT of money doing so, you will lose a lot of reliability, and you will still be sucking wind in comparison to the big bore quads