VB leaking petrol

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Re: VB leaking petrol

Postby MarkOgden » Wed Jan 20, 2021 4:22 pm


Once again all useful stuff ref the adv/ret. I seem to have the standard lever forward for advance. For a VB - What do we suggest "should be" the normal running position for the lever when the bike is warm? I always assumed full advance, but I seem to remember that the lever about half way seemed best, with an option of a tad retarded when going uphill

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Re: VB leaking petrol

Postby will_curry » Wed Jan 20, 2021 5:02 pm

I seem to be retarding the ignition by slightly less than half its travel at the magdyno.
All my ignition levers seen to have more movement at the handlebar than at the mag.
These are all OHV 500s by the way.

Ignition needs advancing as the engine revs rise to allow the fuel the same amount of
time to burn.

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Re: VB leaking petrol

Postby Bob.Murphy » Wed Jan 20, 2021 6:48 pm

I had a '57 VB back in the late 60s/early 70s. I used to run it a full advance on the open road but retarded it a bit when hill-climbing. It would 'pink' to let me know it wasn't happy with the amount of advance.

At speed (relative for a VB) I would have to hold it at full advance while the mudguards split, the bar-end mirror came loose, the silencer fell in half and the fuel tank split around the central mounting bolt. These things can certainly vibrate :lol: .

Back then, of course, it was just a bike and my go-to-work hack so it got ridden hard - I recall heading into Wales with 73mph on the clock, me flat on the tank and thumb jammed between the bar and advance lever. I'd be about 20 back then :roll: .

Two years ago I started getting into MO1 Mags and bought a load of parts. I converted four to take the 'Brightspark' condensers. One is on the VH the rest are spares. I don't have another 'Slack Wire for Advance' Mag but notice that one of my spares has the pickup on the opposite side to what I'd consider normal. Interesting degree of variation in these units.


My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH

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