hi we (me and my dad) are getting bored with the power from our trx250 and were wondering what can be done to fix this problem. ive heard that it can be bored out to 300, is this true? my dad just mainly wants more power without spending too much money so we are down to the fallowing options, please speak up if the mod is impossible or not worth it and give me a price estimate for the cost/ any additional things which need to be done

1) high comp piston, slight overbore


2) bore out to 260-300cc with oversized piston ( tell me if i would need other things like sleeves etc

3) replacing topend with one from a trx 300 2x4 of same year

4) buying a more powerful atv like my warrior

thanks for all the help

 

come on please reply

 

You can't increase the engine size by putting on a TRX 300 topend because it's the same top end.

The 300 [actually 282cc] is nothing more than a TRX250 engine with a stroker crank. This requires a different piston to work, but everythin else in the top end [including the cylinder bore size] is the same.

If you are looking for cheap swap parts to hop-up your 250, go with a cam from a ATC250SX. Your 250 and the TRX300 use the same gring as the 250ES BigRed. The SX cam has a higher lift and longer duration.

If you decide to use a used cam, be sure to get the rocker arms from the same head you took the cam from. A used cam must be used with the same rockers to prevent wear on each other.

If you really want some pep, find a TRX300 engine and then put in the SX cam. Big difference for a "stock parts" engine. The big thing here is the TRX300 bottom end. You can put your top end on top of the 300 as long as you use a TRX300 piston.

If want to spend some bucks, check with Powroll. They used to carry quite a bit of performance parts for these engines.