400ex - more power on a budget

[Jake250ex]

my buddy just put 22'' XTC on his 400ex and is mad that he lost some power and wanted more anyway so I told him I could get hime a good set up for cheap....



I told him to put on a degree key to advance the timing, shave the head .30, put in a xr400 can and get a slip on......



what do you guys thing about that?

[jjohnst03]

Did he regear with the tire change? If not he needs to. That is the cheapest way to get his power back.

Regearing should get back any power that he lost.

[wilkin250r]

Originally posted by jjohnst03
Did he regear with the tire change? If not he needs to. That is the cheapest way to get his power back.

Regearing should get back any power that he lost.

I second the motion.

Plus, I would suggest thinner gaskets before shaving the head. You can even use RTV for the cylinder base gasket, combined with a thinner head gasket would reduce .030 without shaving the head.

[jjohnst03]

Originally posted by wilkin250r
I second the motion.

Plus, I would suggest thinner gaskets before shaving the head. You can even use RTV for the cylinder base gasket, combined with a thinner head gasket would reduce .030 without shaving the head. How much bottom end will you loose with 22" and not regearing? I am thinking about getting a pair of 22" green ball gators. They have them in 22x10x9 and 22x11x9. I would only run them when I knew I would be in the mud so I wouldnt want to regear just for one ride. would I loose too much bottom end to pull them in the mud?

[2muchquad]

yes you will lose a lot of bottom with 22s.not only are they taller which will raise your gearing they are also heavier.you could re gear to help out but you wont be able to overcome physics,they are still heavy:(

[wilkin250r]

Mud is especially bad, it puts a huge load on the motor.

If you're swapping tires, swapping the rear sprocket really isn't that difficult, you have to take the wheel off to change sprockets anyways. Loosen the carrier (2 bolts, or is it 4?), remove the sprocket bolts (4), pull sprocket off. Put new sprocket on, replace sprocket bolts, tighten carrier.

It's really about as difficult as changing the tires, and if you're willing to change tires for a mud ride, why not change the sprocket, too? You can probably go up 3 or 4 teeth before you have a clearance or chain-length problem.

[jjohnst03]

Originally posted by wilkin250r
Mud is especially bad, it puts a huge load on the motor.

If you're swapping tires, swapping the rear sprocket really isn't that difficult, you have to take the wheel off to change sprockets anyways. Loosen the carrier (2 bolts, or is it 4?), remove the sprocket bolts (4), pull sprocket off. Put new sprocket on, replace sprocket bolts, tighten carrier.

It's really about as difficult as changing the tires, and if you're willing to change tires for a mud ride, why not change the sprocket, too? You can probably go up 3 or 4 teeth before you have a clearance or chain-length problem. I didnt know it was that easy. I just got my 400ex last week so I havent done much of that stuff yet.

The stock tires done ok in the mud, but I had to spin them really fast which covered me in mud. I know you are going to get muddy on these quads, but I think with some mud grips you wouldnt have to spend them as fast so you wouldnt get as muddy. Do yall have any other recommendations for tires in the mud on these bikes?

[cals400ex]

it seems like 22 inch rear tires and a 14 tooth front sprocket will make the gearing pretty similar as stock. if you want more power back you could put that 14 tooth front on or you could sell the tires and buy 20's. i would recommend putting in a thinner head gasket and a mild cam.

[wilkin250r]

I don't know if I would bust into the engine just yet, but certainly no problems with changing tires and sprockets.

Many people switch to a 14 tooth front sprocket for acceleration (15t is stock). If you're willing to swap the front sprocket back and forth, 15/38 with 20s and 14/38 with 22s are very close the the same drive ratio.

[RiderTRX400ex]

jet kit, K&N filter, other cheap stuff like that if u dont already have it