No one has asked me, but I think you should put it together and sell it. Buy a bone stock TRX, and ride the crap out of it. Put normal gas in it and have some fun. you have blown up 2 motors in no time at all. Buying a 350 fire breather might give you bragging rights, but where does it end. You will need a bigger/better clutch and then the transmission will go, possibly taking out a case at the same time. Then a new crank. Add in a new pipe and carb, Chain and sprockets (the very best chain for a 350) for gearing, and you will be in so deep you can't see your way out. You are looking for a way to save money on race gas, the price of race gas is nothing when compared to a 350 motor. Swap parts off yours if you want, but a stock bike will last and be fun. There's a bunch out there for sale. Someone has to use some common sense here.
desertR
I think that the above is very good advice for a young guy that does not yet have the money or the experience necessary to own, maintain, tune and to ride these these hybrid engines to their full potential.
The cost of experience is measured in how many pounds of $100.00 bills one has to burn through. Good builders will give you more power, but more power adds a lot of stress to the these TRX 250R engines that their design was bullet proof at 35 HP. The stock CR250 design made around 45 HP but was not bullet proof and required more experience and money to maintain. The cost to own and maintain high HP engines is an exponential function.
The best gear materials 9310, 8620 with the best heat treat processes will never make a 250 transmission strong enough to be bullet proof. The spacing between transmission shafts is too close and the gear diameters are too small. There is just not enough room in the cases to put the necessary amount of metal to handle the torque these new cylinders can generate.
The best 250 Crankshafts, clutches and transmissions are not anywhere as strong as the stock components that come in the CR 500, KX 500 or LT500 engines. These stock 500 singles Make around 45 to 55hp on my dyno.
I can get over 110HP out of the LT 500s. These 500cc engines are very fragile at this level like the 250s are when they have more than about 60hp coming out of them. The guys that are playing at this level have paid for the experience to learn to tune and operate stuff at this level and will continue to spend a lot to keep these fragile toys running.
I have had the above conversation thousands of times with guys before I build them an engine package. Once they realize they do not have the tuning skills, the money to maintain, and buy fuel, they end up having me build something that has a lot less power than what they originally ask for. Are your builders having these types of conversations with you?
