400 to a 440ex help???

[honda400ex01aca]

12.5:1 440cc Big Bore kit. Kit includeds all parts needed to turn your 400 into a fire breathing 440cc monster.Includes a Namura Big bore sleeve 12.5:1 440 Wiseco piston with rings,circlips,and wrist pin and also a Namura 440 Top End Gasket kit.


is this a good kit? and what else would i need to finsh it, like do i need a new head or some thing?? :)

[quadracer500]

you need to install the bigger head studs or you will be replacing headgaskets frequently, extremetecatv.com did mine.
he can also install the sleeve at the same
time, ask for jeff.
he is located in mt.gilead, ohio

[Topeka-440]

Lol….sounds like an eBay ad to me. I bought mine from the same place with the same ad. Anyway everything you need to do the conversion is there, except the machine work of course. There are some options that will make it more reliable too, like the HD head studs, HD timing chain. You’ll have to have the old sleeve pressed out of your cylinder. Then have your cylinder bored out to fit the new sleeve, then have the new sleeve pressed in and bored out to fit the new 89mm piston. Cost me about $125.00 for all the machine work. Like I said I bought mine off eBay and assembled myself, so far no problems.

[400exrider707]

With that compression I would get a heavy duty rod, the heavy duty studs for sure, and the cam chain is a no brainer at $30. Plus the machine work, then what other mods do you have already? Just doing this mod alone will not yield the best results. It will really come alive with a full exhaust, filter, cam, port/polish, and a larger carb like the 04/05 450R carb.

[Topeka-440]

Also I hear you'll have to run "race gas" with that high compression. I have 11:1 and runs fine on 92 Octane pump gas.