Hitchcocks Forum

140 mph 500 Enfield.
90mm bore, 78mm stroke, 8500 rpm, 6 speed gbox...
http://www.bikesportnews.com/news/news- ... ield-dream

Tim
N.Z.

Probably not in standard trim

and needs super unleaded to do it

I have met Steve Linsdell on several occasions, one of which was a guided tour of his bike collection including a previous incarnation of this racer, his Model K v-twin and his 800cc Series 3 Interceptor prototype among others. A very nice guy indeed, very quiet and modest and an amazing engineer and tuner.

REgards, Mark

An amazing achievement from a pushrods single, though probably no more RE internally than a Sometfield is a Manx Norton.

Would love to defrock that bike and leer at its nakedness! There must be a lifetime's creativity under wraps.

Hi Guys----- and thanks TIM NZ for posting this..I'm imagining I'm in those pits and having a "Sneak-peek" at the bike...Here's some random thoughts}--- "I wonder what the all-up weight is ??---From that I could roughly calculate the BHP at the wheel needed for 140mph....Bore/stroke = 90 x 78..... Forged Slipper piston, forged H-Section steel con rod--- roller or needle bearings throughout....Lightweight internals so mass inertia is reduced as is piston linear speed compared to a "Long" stroke but at a price}--- ie Poor chamber filling so is he using 2 small diameter inlet valves activated by big overlap polydyne type cams ??...That 42mm carb tells me that fuelling at top RPM has been a problem.....I imagine the useable power-band is narrow ( Hence the 6-speed box ) but looking at that exhaust can I bet he's using some form of reverse-pulse scavenging to draw extra fuel/air mix into the chamber...A look at the final drive sprocket ratio would help .........I can't see under that fairing but I'd expect a digital electronic ignition system firing 2 or even 3 plugs ( 1 for cold start then 2 for running ) ... only 1 disc up front ? ".............. As I say, just some random thoughts....

Alan,



something tells me he's not using some weird three valve head, read the article again. This from the man himself.



"The cylinder head, timing case, crankcases, gearbox casing - it’s all original old stuff.”



The 41mm Dell'Orto carb is also used (in pairs) by the CRMC BMW sidecar outfits, my friend Tim's 998cc oufit being one of many.



A.

It did occur to me Allan, one disk at the front and a drum at the back?
Enough on the track I suppose but.....