Jules Boag

NO. 1: 1981-1982
This was really basic, using 78mm bore 82mm stroke 1600 cc Alfa engine (EN40B crank, sodium filled exhaust valves,etc) with Wade 4R034 blower. Running straight methanol, sucking through 2x 2inch SU carbs. Using twin SU's doesn't work very well as it difficult to get them to open evenly. Hence the change to hilborn constant flow injection on No. 3.
Alfa gearbox with air shifter and centrifugal lockup clutch (my design).
In retrospect, I suppose it was all a bit much for the 4" Avon. Best run was only 12 @ 120 mph with the tyre still smoking at the finish line.
The engine/gearbox unit was only held in the frame by 3 bolts! Total cost was £250 which was a lot as I was unemployed (story of my life). Only ever ran in one gear, as gearbox couldn't change under power; hence use of epicyclic gearboxes in all later bikes.

NO. 2: 1984-1985

Again all built by me with belt driven cams, reversed head, dry sump oil system, (pump still in use on current bike) 3 speed Pete Davies clutch and gearbox, still using chain primary drive and runing straight methanol. All subsequent versions ran on nitro/methanol mix. I built the frame from CDS2 tubing. For No's 4, 5 and 6 I used T45 or 4130 tube.Rear tyre was 8 inch Goodyear.

NON-Alfa interlude. I bought this injected nitro burning Kawaski in 1985 and on my 1st run had a violent tank slapper. This resulted in a hairy ride across the finish line at 132mph with both legs on the same side of the bike! A second run ended in a crash so a new frame was built and the problem solved.

NO. 3: 1986-1988

Delayed by couple of years of playing with the injected Kawasaki (which ran 8's).
This frame I got from my friend Alex Brachtvogel. Fuel system changed to constant flow injection with rectangular 4" x 3" injector (copied from picture of Vance and Hines fuel bike-block of ally milled out, fitted with 1/16 thick stainless butterfly and EN16 spindle). 2 litre blower and Scintilla ignition. Problems with the gearbox led to:

NO. 4: 1990

I built this to house a new B&J gearbox with Crowerglide clutch and Mallory sprint mag. This had belt primary drive and I made the barrels from solid in one lunch hour, filling two dustbins full of swarf, the pilot holes for bore were 1 1/2 inchs!
I did try 14 inch tyre, but with undersized rim it was unstable.

NO. 5: 1991-1993

Changed to single tube spine frame, all 4130 tubing, (steering head turned from solid). Engine capacity raised to 1820 cc by making new barrels and using offset rods. I usually make all the parts I can for the bikes and on No. 5 I even made pistons from blanks (10 hours each on an old myford lathe). Supercharger was a Weiand. This is the most powerful bike I have ridden, running up to 87% nitro, but was dogged with gearbox problems. I eventually found it had hydraulic seals instead of pneumatic (I was using air). You just cant trust that Mr Trett who I bought it off!! This died at Avon park when I crashed after the rear wheel failed.

NO. 6: 1993

The frame was lower, with Yamaha EXUP front wheel and forks, Mc Gee fuel system. This one was never run and I used lots of the bits for the Yamaha I have today.