Huntmaster Cams and Literature

[jim.haydock]

As you may have read in this months Cheval (Lancs Branch Report) I've discovered that my autojumble sourced Huntmaster engine was fitted with a Spitfire cam as well as a big bearing crank. The bad news is that both are in need of some renovation. Now I've just finished reading Jim Lee's book on Val Page and he mentions in passing that he converted a 57 VB using a 1968 FH engine with Spitfire camshaft and low compression 7.5-1 pistons which ran superbly all over europe. This got me thinking about what combination would be ideal for my own purposes. When finally completed I'm aiming for a bike that I can use on runs and rallies, near and far and which will be equally at home on highways and the byways much beloved of Ariel Club route planners, myself included. What thoughts dear readers?

And on the subject of reading and reading matter, I've also just completed another of my Christmas presents entitled "The Strange death of the British Motorcycle Industry", recently published by author Steve Koerner [ ISBN 978-1-905472-03-01]. A splendid read that thoroughly examines the British Motorcycle Industry from the early nineteen thirties through to the nineteen eighties. Messers. Jack Sangster, Valentine Page, Edward Turner and Bert Hopwood feature prominently in this story so you can be sure that there is a great deal of interest for followers of the fortune of Selly Oak products. I've previously read and re-read Bert Hopwoods account of Whatever Happened to the British Motorcycle Industry and if you've read and enjoyed that fine publication, then rest assured that you'll be fascinated by Steve Koerner's efforts.

Jim

[pete.collings]

I have used the export spec cam (67-356) with 7.25:1 pistons in previous Huntmasters, and think this is the best combination for performance and rideability. The Huntmaster used the thinner flange barrels of earlier A10 size, later A10s and Rocket variants had a thicker bottom flange, as the earlier thin flange had a tendancy to break when the motor was fitted with HC pistons and high lift cams. The later one piece crankshaft is up to the job for tuned motors, I used the earlier small journal crankshaft (easier to get!) which is fine up to the piston/cam combination stated above. I also prefered using an autoadvance mechanism, having tried manual advance, I think it gives better tractability in slow town traffic, where you don't want to be continually adjusting the level of advance using a handlebar lever.
It is still possible to pick up a 356 cam in a good useable condition for a reasonable price at autojumbles, whereas the 357 spitfire prices seem to be overpriced (in my opinion!). The standard cam (67-334) still gives a nice level of performance, although not as good as the 356 (I have a 334 cam to sell if you are interested!!)

[jim.haydock]

Pete, thanks for your contribution. I'm not planning to buy any parts at the moment as my efforts are presently concentrated on building a rolling chassis, but certainly agree with your views on HC pistons and automatic advance. The last thing that I want is motor that is difficult to start, especially when it's been left out overnight at some cold damp rally. So I reckon on lowish compression (7.5 or 7.25 -1) and electronic ignition which should result in easy starting and good low speed running.