Sir Sidney Ruffdiamond
Hero member
- Location
- Cotwolds
Seen Robs update - he’s gone faster today - sure he will be along with the detail - flying Jota 
Elvington 1.25 mile top speed run, 11/12 Oct
- Thread starter Jota Rob
- Start date
I just ran the one day at Elvington.
Mile and a qtr track with speeds recorded at the mile and again at finish. Useful for analysis. I soon picked up on that.
I changed sprocket 3 times, ironic as i removed my regular 19/38 and started 19/35 thro 19/37
May as well have left it at 38 and worked down.
I missed the elusive 150 by 1.2 mph and couldn't do much more than what I did.
If I ran a fairing, purely speculative but I believe I could stick 10 mph on that in the same conditions . Last 2 runs were with one hand, it's that stable.
Mile and a qtr track with speeds recorded at the mile and again at finish. Useful for analysis. I soon picked up on that.
I changed sprocket 3 times, ironic as i removed my regular 19/38 and started 19/35 thro 19/37
May as well have left it at 38 and worked down.
I missed the elusive 150 by 1.2 mph and couldn't do much more than what I did.
If I ran a fairing, purely speculative but I believe I could stick 10 mph on that in the same conditions . Last 2 runs were with one hand, it's that stable.
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piranha-bro2
Hero member
- Location
- Melbourne
Nice stats, Rob!
So your highest speed at 1.25mi was running the 37T? What revs for each run? Pretty healthy speeds for an unfaired bike. What tuning mods to the motor - I notice the 3/1 ... and Mikuni flat slides?
So your highest speed at 1.25mi was running the 37T? What revs for each run? Pretty healthy speeds for an unfaired bike. What tuning mods to the motor - I notice the 3/1 ... and Mikuni flat slides?
Vmax from standstill Piet , same point at the start of the runway on the left in this pic.
Rob
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Vincent, last 2 runs, I had my left hand on the tank steadying my helmet as it is touching the tank. Rock steady. I was told to fit a steering damper so I had ....I believe it would have been the same without but a safety precaution. Tyres are Continental cr3
If you find that article, I'd like to see it, has disappeared off the net.
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Yes, that's correct, highest speed on 37 teeth, just shy of rev limit which is currently 8200 rpm. I ran out of time to try a 38t.
I've not dyno'd since a complete rebuild this year. I will be doing so after a few checks and adjustments and probably some new cam followers.
It's well documented from the past. Head, ceramic coated everything up top, new pistons, carillo, rs38, home made exhaust, ignitec. Lightened crank and inlets by Red. Will be good to compare the chart with 2012 when it's been optimized on same rolling Road .
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Hi Rob, you might try looking for some information regarding the old 125cc 2-stroke days. They would ship the riders to Japan for wind tunnel training. Just arching your back had a big effect on top speed, or pulling those massive pommy number plates off, even. No idea how you did 3 rear sprocket changes in a day, it's a big job to change one on my 3c.
Seems like an awful lotta work, this picture should help.
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andre g
Hero member
I thought so, nice drag bike and 240 km/h without a fairing is impressive, well done
piranha-bro2
Hero member
- Location
- Melbourne
It's not a QD hub, Vince. 3Cs and SF1/2 had QD hubs - and the part that stays in the frame is the cush assembly and sprocket, so you'd be pulling it all off anyway. No big deal pulling a wheel out and R & Ring 5 or 6 sprocket nuts.
I ran 149 without fairing on 2nd run, 1st run was sighting lap.
Hit a wall with fairing, redlined with 38 tooth, switched to 36 tooth and got same result. Swapped to velocity stacks and bigger mains, same result, last 2 runs..
Hit a wall with fairing, redlined with 38 tooth, switched to 36 tooth and got same result. Swapped to velocity stacks and bigger mains, same result, last 2 runs..
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piranha-bro2
Hero member
- Location
- Melbourne
Nice work, Rob. Will you manage 250kph (currently at 247kph) is the big question!
No, same result, but the stacks were running on 138, pods on 132.
The video is here on Facebook , its not mine so i cant upload it directly.
Cheers Rob
https://www.facebook.com/share/v/1DPjWNacVz/
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Andy J
Hero member
- Location
- Isle of Man
Good result Rob, I doubt there are many people who have done a genuine 150+ on a Laverda (and have the paperwork to prove it).
I'd give it a try without the stacks... or use shorter ones. Check out the shape of Reds racing intakes, way to go!
An hour or 2 with the carbs on a flow bench will most probably unleash a couple of ponies.
piet