johnsbantam

Thanks everyone for the interesting disscussion. Perhaps I should have written a longer question. I live in New Zealand, Though (Charlie) I grew in Banbury area and lived in Brum before emigrating. I actually have a Bantam trials bike with a D7 175 motor, which is probably lighter than a Cub ? I am currently using some Betor forks off an old 70s trail bike; too log, the geometry is all wrong and the springs a bit soft. Presumably you guys are referring to Betors as on Bultacos and Marzoccis as on modern trials bikes ? looks like I will have to send some sliders over to Serco.

Can anyone tell me how I can get in touch with Serco or how to use modern fork tubes and yokes /modify Tri Cub Sports 1.375" fork sliders ?

Regarding Tubeless tyres; I guesss it depends on the difference in size betwwen rim and tyre. I have run a tubeless Dunlop for 4 years with no problems. In fact it was very difficult to get it on and tight to get the bead out on the rim. My local mechanic swears by blowing up tyre to high pressure (75 - 80 psi) leaving it overnight. I did this and happily run 4 - 6 psi in rear.