Originally Posted by williamr

Being more serious, for a drastic increase you must start by increasing compression. Best done by milling the head unless you can find aftermarket high compression pistons. Open up and flow the ports at the same time. Then change the cams. Versys inlet cams in both inlet and exhaust are good. The TBs must be opened out and to suit them you'll need to make up new butterflies. You can ignore the secondary butterflies, although omitting them will result in poorer response when the throttle is snapped open from low revs.

You'll then need a decent exhaust and an opened up air box and free flowing filter. After that you can use a juice box or power commander to set up the fuelling to suit, and you'll need to re-map the ignition advance curve. The finished engine will need high octane petrol.

A turbo, and boring out the cylinders to increase capacity to 750cc are also worth considering, although the overbore is more for enhanced mid range capability.

Juice box or Power Commander,exhaust, air box mods and filter will give you a little, but not really very much.

By the time you've learned (and earned) enough to do all that work you may know how to ride it.

The first line of the Juice Box advert is semantically disingenuous.
• Allows addition of fuel required with engine modifications without upsetting stock fuel map.

It works by altering the ecu outputs - ie, modifying the stock fuel map on the fly. If it was possible to alter the stock map internally then there'd be no need for things like juice boxes. On some bikes you can alter the internal maps, and that's a better option than these things. Anything that alters the fuelling should be set up with a dyno and ega. Guessing and 'rider feel' are not good enough.

Rob