I am thinking of buying a 85 250sx 3 wheeler,does anyone know if this engine is simaler to a 250x.Can you buy parts to build them like a 250 or 300ex?Are they worth doing?Thanks for any input.Daryl

 

I have 2 85 SX's. They have an auto clutch, reverse, electric start, and shaft drive output so they are pretty different from the 250X. Just like any engine I'm sure you can mod it but I'm not sure if parts are available. Sx's are very reliable and if it runs good and looks ok I would think its worth about $800.

Woodo

 

Thanks Woodo68 I will check into engine mods before I buy,the want $750.for it.I thought that wasn't to bad.

 

A 250x top end will fit on the motor, ONLY if you put the whole works, cyclinder, head, piston, cam ..
You should be able to get a little more performance from that mod, i don't know anyone personally who has done it but after examining the two motors (well close enough, 97 300 4x4- same head and cyclinder).

 

The 250X top end WILL NOT fit on your engine. The spacing on the cylinder studs aren't even close to being the same. TRX 300's top end parts WILL fit but you don't want them. It will only slow you down. Before the big aftermarket boom on fourwheelers hit about 6 years ago, the guys running the 300's actually scavenged salvage yards for 250SX parts. That 250SX has one hot cam straight from Honda. Do not confuse this with the 250ES engine. The Big Red engine was the same as the SX except with different cam and the transmission gear ratios are different.