400 EX Motor Work

[Hondaistheshiz]

I plan on getting a 400 ex soon. I have to be able to at least beat a piped z-400 in a drag race. So here's my ordeal. I want to bore out the cylinder, is a 440 unreliable? or should I get a 426 instead. I am goign to get a Curtis Sparks x-6 exhaust system, a Curtis SParks Aggressive cam, and then get my engine orted and polished. Would I be able to beat a 4 with a pipe in a drag, and maybe a totally stock raptor?

I really wanan know what kinda differences in power there is between a 440 and a 426 and if the 440 is unreliable.

Thanks,
Danny

[EXDUNER127]

The only way a 440 is going to be a bigger difference is if you do the works, hardened rockers, hotrod, race p&p, hd cam chain, better carb, because you wont get. if you port the head, plan on getting a carb to get the full potential. i would go with the 426 and you will be fine. i have just full pipe, fcr39, full port n polish, advance key, rev box, and i beat stock banshees up olds, z400 and some piped rappys not knowing what else they have done!
soon i am going to a 416.

[Hondaistheshiz]

isnt the stock carb 38 mm??? Does 1 mm make a big difference?? Could i just get my carb bored?? Would that do anything??

[tinner]

I believe the stock carb is 35.5 mm. I have a stock bore that's pretty done up, but my brothers 440 really has alot more torque. This winter I will punch it to a 416. I don't know if I really want a 440 kit.

[Hondaistheshiz]

oh well on hondas site, it says 38mm, idk. Wil la 416 or 426 keep up with the 440?

[Natertot426ex]

A 426 is the way to go. I have had mine in for 2 years now and it is still running awesome. I have my head ported and the stage 2 cam and running the edelbrock. It has plenty of power.

[Giz400ex]

My 400 was a 406 and this spring we punched her out to a 425/426 and she's grabbed a bunch of torque.

[Rico]

Originally posted by Hondaistheshiz
oh well on hondas site, it says 38mm, idk. Wil la 416 or 426 keep up with the 440?

38 carb is a typo since the part numbers are the same for a 2004 400ex and a 1999 400ex. and a 99 400ex says it has a 35.5

and yes a 416 will keep up with a 440..:cool:

[400-416EX]

I have a 416 kit with edelbrock carb, full race port and polish, and the bike cooks. What huge difference over stock. 416 and 426 are the way to go. I have a few friends that run 440's and they always seem to be wrenching on there bikes. But a lot of people like them.

[400exracer511]

While were on the subject, im tryin to decide if i want to go to a 416 so about how much will it cost me when its all finised if i go with a 416 with a ported head and cam?

[400-416EX]

All depends on who it send it to. If you don't have anybody in mind Give extreme atv a call. There # is 860-892-4033, speak to mark. They did my motor and there machine guy does amazing work.