Ok.. the 3 tracks within a 70 mile radius of me are all 4th gear only (Or some use 2nd only in their CR500's
) .
I don't know anyone who is shifting at any of these tracks.
Anyhow I wouldn't abandon your center flapper if your cylinder is a 89 and newer.
Having the longer usable power curve gives you a advantage over the CR500's.
Find some heavy duty clutch springs to help keep your power on the ground and not slipping the clutch
On the vid I posted earlier, if you can get the measurements asked for on it I can calculate your compression ratio and see what cc head you should be using based on the fuel you want to run..