400EX Upgrades

Honda

Hello,

Im getting ready to tear my 400ex apart cause the rings are done in it and i want to bore it i just need to know what size is best. I heard the 416 bore is the best since it has a lighter piston than the 426 and the 440. Also i was wondering if i should put a stage 1 or 2 cam in it as well. Respond to this and give me feedback please.

416 is most common because it offers the best performance to reliability ratio. The 426 and 440 kits can allow the motor to run a little warmer than an air cooled motor should run, especially at slower trail speeds. Get no more than 11:1 compression ratio if you want to be able to run on pump gas.

As for the cam, I guess that depends on the type of riding you do. The Stage 1 cam has a large bttom end hit with a little better midrange, as well and is very popular on the trail or in XC racing. The Stage 2 has slightly better bottom and top than stock with gobs of midrange and is usually the choice for MX.

When I rebuild I'll be going with a JE 10.8:1 416 kit with a Stage 1 Hotcam.

I would go with either the 425 or 440 kit from these guys.

http://www.powroll.com/P_HONDA_TRX400EX.htm

...stock bore or +2mm..the same as a 400 or 416!!

These guys have been in the business for decades.

What do you guys think of the wiseco 400 kit? I do fast trails and some sand pits.

I would go with either the 425 or 440 kit from these guys.

http://www.powroll.com/P_HONDA_TRX400EX.htm

...stock bore or +2mm..the same as a 400 or 416!!

These guys have been in the business for decades.

They have been around a long time and are a reputable company but if you pay those prices for parts you're riding the sucka train!

What do you guys think of the wiseco 400 kit? I do fast trails and some sand pits.
Well it's a stock bore so unless you're bumping the compression there isn't much to think about it at all.
They have been around a long time and are a reputable company but if you pay those prices for parts you're riding the sucka train!

.......LOL............:bonk:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now