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Bullet runs at UK Speed Week

Posted: Thu May 19, 2016 8:03 am
by Martin C
I've previously done quite a few standing-start quarter-mile runs at Santa Pod dragstrip RWYB days (and have a third-place trophy from a Danish classic sprint) event, but I've long wanted to try an officially timed top speed run in safe & legal circumstances. The UK Speed Week 2016, organised by the 'Straightliners' seemed like a good opportunity.....

The 2002 bike has the Hitchcock's GT Cafe-Racer kit, with the Hitchcock's 612cc road-spec engine mods & 5-speed gearbox conversion, plus the belt primary-drive & clutch, with a small handlebar 'bikini' fairing. It runs on ordinary 95-octane fuel with Castrol Valvemaster "octane booster" additive, and is road-legal apart from the noisy exhaust (megaphone with reverse-cone end, no baffles). At 5' 10" and almost 14 stone I'm no lightweight.

Last Saturday (the first day of Speed Week) I did 4 standing-start mile runs at Elvington airfield, in the RWYB class, and achieved a terminal speed of 97.154 mph, with 2 other runs within 1 mph of that. I was revving to 6,200 rpm through the gears, and seeing 90 mph in 4th before changing to 5th.

There was an almost-headwind gusting about 8 to 15 mph, and at the finish line the bike was still slowly picking up speed in 5th gear, so it would doubtless do over 100 mph with a longer run up. They have a strict noise restriction at Elvington (due to a whinging neighbour), and my bike initially failed scrutineering due to exceeding the 100 decibel limit on the open megaphone, so I had to re-fit the reverse-cone to be allowed to run. I know from experience that the fully-open mega does improve top-end power above 4,000 rpm, so I'm fairly happy with my result - for now.....



Bullet runs at UK Speed Week

Posted: Thu May 19, 2016 5:43 pm
by Barry N
Presumably this is you then Martin?
By the way, what gearing were you pulling?

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Bullet runs at UK Speed Week

Posted: Fri May 20, 2016 12:41 pm
by jefrs
Nice run!



I routinely used Castrol Valvemaster octane booster when all the fuel went unleaded and my old car had 'soft' valves. Never had any problems with that engine so the lead-replacement worked but I never noticed any significant octane boot. I mainly run on pump 98/99RON now, mainly because it's the cleanest available.