Thanks for the answer.
I have just bought the Cub (non running) and my trialfriends says that 199cc is not strong enough. Maybee i chould try it for one sesong first.
I have Doyer Bransden, R-cam and 7;1 piston and Kehein carburettor. I had not try it in sections yet. So far i have drive my TLR250.
If I find it to weak I start with some later cases as Subira told me, but I like to do it myself as I have the machines.
I have a 199cc Cub never had a problem with power in normal pre65 trials (im 15 & a Half Stone)
Vinnie