does anyone know the very most power you can get out of a 400ex? If you can please list the parts. thanks HONDAS RULE

 

the most i've seen out of an ex is like 52hp's. thats the 440 big bore kit , race cam, titanium retainers, ported polished,3 angle valve job, high rev ignition,new valve springs, and the crank stroked 4mm . i talked to a gentleman from trinity racing , that is who i got this info off of. he told me one guy stroked his 6mm and it did not last but a few weeks, the crank had broken.

 

the most i've seen out of an ex is like 52hp's. thats the 440 big bore kit , race cam, titanium retainers, ported polished,3 angle valve job, high rev ignition,new valve springs, and the crank stroked 4mm . i talked to a gentleman from trinity racing , that is who i got this info off of. he told me one guy stroked his 6mm and it did not last but a few weeks, the crank had broken.

 

To get lots of power, more displacement is needed. A 440EX is best deal in my opinion. IMS has one of the most reliable big-bore kits out there. Since 1996, they have been making a 440 kit for the Honda XR400 dirt bike. The 400EX's engine was borrowed from the XR, so reliability and power gains should be similar.

Check out the January '00 issue of Dirt Wheels. They tested a White Brothers 440EX and loved it. Take into consideration that a 440 kit, which will give you a substantial boost in all power ranges, will be a money pit. You will have to buy the 440 kit, a new cam, exhaust system, air filter, clutch and suspension. The stock clutch wasn't built to handle an additional 10 horsepower, and neither was the suspension.

The 440 kit, with all the above mods, will cost around $1100. New front suspension and a rear shock revalve will cost an additional $600-900. Labor costs will depend on your shop, but it won't be cheap.

I hope I'm not discouragine you because I haven't heard any complaints about a 440 kit on a 400EX. Zero problems. IMS has been making a 440 kit for 4 years now, so they've had plenty of time to work out any problems. Beef up the clutch and you should have a machine with reliability close to a stocker, and that is saying a lot.

 

One of the kits I'm looking at is LRD 440.

Bore and sleave cylinder,11.5-1 coated piston,Recreationial cam ( all range)Valve springs biger three sided valve job, full port,39 mm keihin FCR carb ( same as yz400f)11.5 cdi.LRD pipe and header,And a bunch of little stuff.

Claimed hp 46-48 depending on casting grade.
Price $1995 + pipe $260.
Just the carb is $425 included.

note-- Must be run with race oil and race gas 116 octane.

This is getting expencive! But hey real power is not cheap.

Mike, You just had to say somthing about that clutch. Now I,m starting to worry,,,,,,,Thank's

[This message has been edited by trx430ex (edited 11-30-1999).]

 

More power would be nice, but it is expensive. I am content with stock power. The only mod I've made on my '99 400EX is Renthal bars with Scott grips. I only did that so I wouldn't bend the stockers. I plan on keeping my machine relatively stock, partly because I am kind of cheap, but mostly because I'm very happy with it stock. Stock is pretty good, and I'd rather worry about improving riding technique than buying mods. I would consider a new carb/exhaust/air filter setup to improve throttle response. I think a new carb would be key for better throttle response.