Will a 1994 HONDA TRX 300 FOURTRAX head....

[Tri-ZNate]

Bolt onto a 250sx? I have heard some years will bolt right on and give your SX like 286 or so cc's. Is this one years that will work? If so I'm gonna snatch it up, a friend has one and only wants $20

[TimSr]

I dont know if it will fit, but you cant change displacement with a head. You can only change it by changing the bore size or the stroke length.

[brapp]

thge head cylender and the piston.

[Jason T]

I'm 99% sure the head will fit, but as TimSr says you won't change the displacement. I am also sure the 250 and 300 share the same size bore, so you need to change the crank and rod to increase the capacity :D

Jason T

[slothminx]

where you measure the displacement of an engine, is the hieght of the cylinder when the piston is at BDC(bottom dead center) and the bore of the cylinder even mugen cant make the head change the displacement of the cylinder. the head yes does have a certain volume to it and is not flat to the top of the piston (lol pretty serious compression) but im afraid you will not be able to bolt on a head to your 200x that will change it from 200cc to 250cc etc.


that was from a post about mugen heads and cylinders ;)

[Tri-ZNate]

errr sorry brain fart I meant the cyclinder. The head will fit a 300 because it goes on a 300 :lol:. So the cyclinder off a '94 will bolt on?


Also he has a '97 300 head and cyclinder that he wants $100 bucks for. The difference? The '94 cyclinder needs to be bored out and the '97 is ready to bolt on. I'm thinking that the '97 might be the way to go if it will fit.

[brapp]

but the earlier 95 aqnd before have more power diffrent cam and valves.

[Tri-ZNate]

hmm ok then. I think i may wait then and look on ebay for an early cyclinder and head that are ready to bolt on. Thanks guys.

[Lomax]

Are you just needing a new cyclinder ? If your trying to make it a 300 then thats not going to work, both engines use the same piston. It is the stroke thats different. There used to be a company that made an actual 300cc kit fot the old 250's but I do not remember there name. A little internet searching might turn something up.

[Tri-ZNate]

I'm just looking for something to make the SX a little more peppy without cammin it. If the 300 top end doesnt displace more cc's then hopw do guys make the 286cc SXs?

[Jason T]

I don't think there are many 286cc 250's around ;)
Have a read of these it should tell you what you need :TrikesOwn

http://www.3wheelerworldforums.com/showthread.php?t=38932

http://www.3wheelerworldforums.com/showthread.php?t=37678

Jason T