Lost member needs Fourtrax 300 swap in a Sx hel

[AtcFactoryRacer]

Hello guys, I am an old member to this site but i havent been on here in about 4 years, not because i got out of 3 wheeling(i ride 3-4 times a week) i just lived without a computer for a while. Anyway, I have two 85 Sx's, one i ride, the other i am building with a 300 fourtrax engine. I am currently fabricating a new 2inch extended swingarm out of stock swinger pieces, and i am modifying the frame to accomodate a 250r shock and linkage. My buddy is a machinist he is making the extended driveshaft. I am wanting to build the 300 engine where i can get more power, but run the stock carb and a modified stock 400ex silencer. What are ways to build power out of these engines. I read someone was running a 4 valve head, maybe off of a 300ex? Is it possible to run 86'-87' trx 350 engine parts in the 300 cases? just want to explore my power options, once the frame is done im gonna sink money into the engine.

[bcredneck]

the original 250 motor spins backwards so there may be problems with motor or motor part swaps

[Name Brand]

You may have an easier time swapping in a TRX250 rear end in; not much fabrication required. It is 3 inches longer than the SX.

Look at the link in my signature to see how I did it on my SX.