Ok,no takers then.

I am looking at three options:

1. Grinding a 2mm offset in to the big end pins. This will give a stroke of 58.5mm
2. Having new crank webs made, with an extra 2mm diameter.
3. Do nothing.

Option 1

This will be the easiest method, but will require the pins to be re-nitrided to ensure the correct hardness for the big end needle bearings. Secondly it will require a 4mm spacer and a drop of the port heights. It will also require a grind of the crank cases to ensure there at least 1mm clearance. It will also require a new conrod with a length around 108mm between centres if I keep to a standard Honda piston..

Option 2

This will be the more expensive option. For machine time/cost, full circle crank webs will be the best choice. However, this will reduce the crankcase volume (not good). The new webs would probably be stronger than the resized crank pins. It will still require a spacer to raise the barrel and port height adjustment etc.

Option 3

The cheapest option. I have ridden a Tyga 300 and absolutely loved the mid-range pull, but wasn't happy with the sudden top end drop off. The engine has so much more potential. Gaz, who owned the bike said it was dyno'd at 79 bhp (GP Performance - Fuchs rolling road dyno). It definitely felt that strong compared to my 250, as it could easily keep up with the 600s coming out of the corners. It was the straights that was the problem, just ran out off puff! Gaz's bike had pretty much the full Tyga bling except he was running standard heads (both had rears fitted). I'm pretty certain the standard Tyga pipes are not optimised for the 300, as the pipe's volume was designed for the 250.

Regards
Dave