Sprint Bike 1967

[john9700]

Surfing the net as you do.. I came across this rather purposeful looking machine, dating from the first meet at Santa Pod 1967.
I wonder if it had Greeves Roadster hi-comp cylinder heads fitted? Engines must have been tuned in some way and wonder what ever happened to the bike after that meeting?
Be interesting to learn more.. e.g. performance of standing quarter.. etc.

Image borrowed from 'SelvedgeYard.com'

[IanCordes]

Nice one! They have a single S25 carb each, and a cut down Villiers silencer, so not much sign of tuning here! My understanding is that all past attempts to tune 2T/3T motors had met with very limited success, so I can't see combined power creeping past 40bhp at best, and probably less. I read somewhere they weigh 95lb each, so 190lb of engine weight alone. He would have emptied the gears out of one of them, no doubt. It would have been interesting to see the primary side. An overweight, rather flatulent but brave and skilled attempt, by the looks of it! I like the Villiers twins, but most of that is to do with the sound of them. I bet two together on full song sounded fabulous! I wonder if they were 250's or 324's?

[John Wakefield]

Twin engined sprinter

I recall seeing the double engined Villiers bike (or one like it) at Duxford airfield (now the IWM) in the 1960's when the NSA & other clubs held sprints there.
Ian your right about tuning the 2T & 3T is very limited mainly owning to the very restrictive transfer ports on the inner cylinder walls, & there is also the problem of overheating again due to little or no finning on the inner cylinder walls which causes seizure, although this would not be so much of a problem with the short runs in sprinting, and running on methanol would keep things cool.
The engines on this bike as you say still have standard S25 carbs & their restrictive manifolds, I am sure some gain in performance could have been made with twin carbs per engine, or at lest a large bore one on less restrictive manifold.
This bike looks like the work of an amateur to have a bit of fun rather than a serious attempt to record quick times. I wonder who the rider was, in some of the pics it has R Perkins listed but this may have been the photographer rather than rider.

[IanCordes]

I was forgetting about methanol, which would give its main power boost. I like it though. I guess he had a double engine sprocket on the rear engine, coupled by chain direct from the front engine, which has no gearbox casing even, to allow the exhaust run on the rear engine, and carb clearance on the front one. Neat!

[john9700]

Engines

What a great cheap-as-chips bit of fun could be had whilst around that time Pride & Clarke were selling off old stock of these Villiers units..

[John Wakefield]

What a great cheap-as-chips bit of fun could be had whilst around that time Pride & Clarke were selling off old stock of these Villiers units..

And a SPECIALLY TUNED one with 10:1 heads for only £31.10

[Stuart Baskill]

And a SPECIALLY TUNED one with 10:1 heads for only £31.10

How about this from Stafford 2015.Road test reports quote that engine as 61mph max.I want one of these Anzani engines if anybody has one for sale