Farm Implements
The basic layout is simple: dope-burning 500cc single, steel tube frame, sprung front and rear ends. But it's the levels of development, adjustment and build within the 500 solo class that fascinate. The current fave frame is the monoshock Nu-trak, with fully adjustable suspension geometry, but older items from Antig, Dula and Maximum can still get results in the right hands.
The Czech Jawa is the most popular powerplant at the moment, followed by the Italian GM lump, and British Godden units are still doing the business in the right hands. These engines run total-loss oil systems: castor oil carried in the frame top-tube is pumped in and then out of the engine - no recirculation. And they suck cool-burning methanol to keep engine temperatures down and power outputs high. Brute simple.
The trick with set-up is to get the gearing spot-on and make sure there's just the right balance between traction and wheelspin by adjusting frame and swingarm geometry.
Two-speed gearboxes are Bewley items and the laid-down engine configuration is now a must for big-time racing if you're planning to spend any time at the front. You won't be needing brakes at National level either.
Tractor Boys
With a 1000cc upper-limit (and a possible 1045cc for next season) Yamaha EXUPs and R1s and Kawasaki ZX-10s are the favoured lumps. Outright power is important, but not as vital as getting drive. With 150bhp on tap through a 4.00 x 18" trials tyre (speedway pattern for dryer surfaces), set-up is vital.
A huge range of adjustment via the rear wheel spindle is largely what makes the difference between an outfit that will steer beautifully with no grip and one that has plenty of drive but won't turn. Needless to say, hurtling towards the trackside scenery at full bollocks unable to alter your trajectory is not ideal.
Chassis are mostly Steer devices (made by a bloke called Mick Steer), although the odd Antig or SGM can also be found. Gearbox internals are substituted for a strong, simple two cog set-up and the punishment these things get has to be heard to be disbelieved.
Oh, and sidecars are allowed brakes.
