cheap way to bore 300ex

[T_bling11]

how do you bore 300ex to a 390 in a cheap way

[01exrider 281]

I DONT HAVE AN ANSWER. MY GUESS IS THERE IS NO CHEAP WAY TO DO. OR IF IT IS CHEAP IT PROLY WONT HOLD UP

[bwamos]

With that large of a bore change there is no cheap way at all.

You are going from a 282cc (76mm) to a 389cc (87mm) piston. Almost half an inch larger

You are going to require a special sleeve (perhaps a modified 400ex sleeve?), major piston cylinder boring (aluminum part), machine work on the cases to make room for the new piston sleeve, the head will have to be reshaped to extend the dome out to the new piston size since it is such a drastic difference. Etc.....

It is going to be pretty dang expensive.

If you want cheap, you need to stay below 300cc's.

[kukerdan]

Go to a farm, and let a big *** pig go crazy on it

[honda300EXtreme]

yea as bwamos said
there is no true way to build a large bore 300 in a cheap way, there are too many modifications required to your current set-up to even refer to the term cheap

if your looking for a larger bore, i would not exceed 330 cc's (80mm) four stroke tech sells a 330 kit that usually does not require clearancing the lower cases, the kit its self is 295, and the boring of the cylinder and sleeve can vary and where from 100+

when your talking 300ex engines displacment is not always the key to making optimal power, the head is very retrictive of air-flow and larger valves and a port and polish can benefit your motor greatly, how ever this is not cheap either

i mean for the cost of properly building a 300ex, you can buy a decent 400ex,

[87redrider]

Originally posted by kukerdan
Go to a farm, and let a big *** pig go crazy on it :D I'm with stupid!!