LCGB Forums

Hi, is there a quick way of checking a rapido barrel to see if it's a race or classic? Got a kit which came with an escort 2 ring piston. Not got crank in yet. Seller couldn't tell me and I've not seen one before.

A race rapido has a higher/bigger exhaust port, if you measure the top of the port to the top of the cylinder the race will measure around 34mm the classic around 37mm

Thanks Scotty, it's 34 mm so a race then. I've trawled the million rapido threads, and will be using 58x107 crank, 30mm phbh preferably with a filter, and a clubman. Wondering what anyone recommends for gearbox and sprockets, for 1 up mainly. Got GP 200, SX200 and late pacemaker gearboxes.

look to gear it at about 4.9- GP200-19x47 or pacemaker 18x48-should be ok with a clubman

Cheers

Unless you are committed in some way to the 58 mm stroke, you should consider a longer stroke as a means of juggling port timings.

I don't use PH (or any round slide carbs designed for a four stroke), but the 30 mm VHB two stroke carb equipped Rapido 70 mm x 61 mm stroke I have easily pulls Pacemaker with 19 x 46 which is TV200 equivalent. Through an air filter & a home made 'Clubman' with a l-o-n-g reverse cone

I ran mine with a 28mm phbh, BGM clubman, 58x107 crank, 19x46 with an Italian GP 200 box.
Lumpy as hell low down and topped out at 70mph.
The lumpy ness wasn’t cured until I fitted a TS1 piston and an aftermarket Reed, but by that time I had a PM pipe on it.

i run a 225 race with a 30 phbh,58 x 107 , bgm clubman and sx 200 gearing, its a really good set up and pulls cleanly from low down, tops out around 70 ,,