It would probably be easier, cheaper, and more effective to just transplant the engine from a 600 cc sportbike into it. Or for that matter, an even bigger engine. The engine speed is limited by the relatively long stroke, and there isn't much that can be done about that. That leaves increasing torque as the route to more power, power being the product of torque and rpm. Torque can be increased only by increasing average cylinder pressures. You quickly run into a limit there with the limits of fuel quality, and will have to move to ethanol or methanol to get the higher octane required. You could try to find high octane racing fuel, at quite high prices, if you preferred. You will be interested to know that these are the very same limits that have existed since the days of the Model T.

well ive looked for parts for both turbo build and all motor at its about the same price unless someone knows where you can find a piston and ring set cheaper then 160$ if i were to swap motors to a sport bike you are very limited to motors because you cant fit a SV650 motor the only motor that might look good in there would be  a twin cylinder maybe a kawi 500R motor  unless there are others that i havent seen! well any help is appreciated i would like to start getting parts soon so that i will have parts by late summer early fall to get the build underway!

Oldfeller--FSO wrote on 03/02/10 at 15:01:22:


The thing I'd worry about is dropping the bottom end out like Torque did to his bike.  Torque like to ride hard and fast if I remember.  He replaced the savage with a sport bike after the bottom fell out.

The question that must be asked - of yourself - is "What is the object of the exercise?" Do you want to push the limits of the 650 cc single in the Savage/S40 chassis? Are you trying to make what you already have perform better? Or are you looking for a more powerful/faster bike without much regard to the chassis? Once you have answered that question you can decide how to proceed. In terms of top speed, a 250 Ninja that retails for $1000 less than the S40 will happily outrun the stock S40. A 600 cc sportbike of any make will outrun, outaccelerate, outbrake, and outhandle anything you can do with the S40. Only you can decide what you want, but it helps an awful lot if you define your objective in advance. Remember too that the S40 has brakes and suspension that are adequate to its basic performance, but probably not up to much more.

Sounds like your trying to do to yours what Im doing to mine.

Ill turbo it eventually, but its alot of parts and money and many factors for error. A destroyed motor is easy to accomplish.

pitbullcustoms wrote on 03/03/10 at 16:18:24:

pitbullcustoms wrote on 03/03/10 at 16:18:24:


Interested too. Can you post a link or contact?