hello from a state of disassembly.

lindie

Well Known and Active Forum User
Non-VOC Member
g'day. am currently readying my little girl for use after a long hiatus of stagnation. may as time goes by drop in to pick a brain or two.

she's equipped with a 45 and 48 toother on the rear hub and i'm wondering whether one would be more suitable for the occasional trundle with a painfully low national speed limit of 60/70 mph. meant to be lightning cams and by notes scribbled in the owners manual 8 to 1 slugs at original bore by the "STD" stamp i saw through the plug hole (is there a determining stamp on the crown as to the compression ratio?). bottom end is rapide though no idea of the internals.

it won't be receiving a new chain till it's ready for roadworthying so the 45 is likely to be the one used for any initial test rides. rear wheel is a 19" and by my reading 100 mph would be 4500, and 4800 rpm, which by my calculations is 2700 and 2880 at the 60 mph which i'll be tentatively required to stick to. this is my first big banger v twin having only dads gs1100g suzie and my mz es250/2, dt200 yammie and rg250w suzuki two strokes as reference and a run on a borrowed harley that i thought was an overrated and weight piece of ****.

obviously the 48 would be better in traffic but the plans to use it for mainly highway runs. is the near standard 45 going to be the better for that and user friendly enough round town too as the chain isn't notably worn? or will the cams and comp knock the low speed torque around and make the 48 a better proposition?

thanks for your time, glen.

p.s. will be joining the VOC soon as i'm more suitably prepared now than this time last year. apologies to Vince Farrell and David Hills for the delay.
 
Last edited:

deejay499

Well Known and Active Forum User
VOC Member
Hi Lindie. A 45t rear sprocket is Lightning gearing and check that the front is only 21t as 22t was also used for Lightnings. Personally I would start with the 48t to give you easier take off until you are more used to the bike then decide which way to go. Have you got a standard Vincent clutch, as they are a bit of an acquired taste and can be sharp,:( so again the 48t could be better, certainly in traffic.
Good luck with it, DJ
 

lindie

Well Known and Active Forum User
Non-VOC Member
thankyou dj. don't think there were any nonstandard clutch conversions around when she was spannered together(late sixties, early seventies. family owned bike but owner passed on.) but i haven't popped the clutch cover yet or been at the front sprocket to check it out. to all reports it was used exclusively for high speed thrashing in the 140mph region so i'll have to have a look to verify. bloody clutch cable is broken unfortunately and the decompressor mechanism appears to to have been removed so a cable swap isn't feasible. i would of thought that the single plate would be a nice operation if nothings warped or the springs aren't stuffed. i'll defer to you on it though as i've not tried it.

evidently the length of stroke and two pots acting as a unit would endow a fair whack of torque, but where would you expect the first good usable range to kick off? how low are they generally to idle and are the flywheels pretty weighty? they look like a decent sort of lump of steel.
 

Tnecniv Edipar

Well Known and Active Forum User
Non-VOC Member
If your not familiar with the unique design of the Vincent clutch you are in for a surprise !! Properly set up it's superb , light and progressive , but if not it will anywhere from difficult to horrible !! Don't let anyone persuade you to fit any other clutch though , it's one of the Vincents defining features.
Low speed torque is brilliant , these motors have a very wide torque curve.
 

bmetcalf

Well Known and Active Forum User
VOC Member
Meet up with the local section. (Although here in the US, that could be 100's of miles away. Maybe the same for you in Oz.) Another owner's bike and advice would give you some clues.
 

lindie

Well Known and Active Forum User
Non-VOC Member
thankfully she came with an owners maual, paul richardson's "the vincent", 1960 printing of motorcycling magazines maintenance series on the B through D range, and a spare parts list for B and C with the 52 and 54 supplements. the clutch doesn't look that daunting and evidently works well if set up right or they'd never have achieved any status in the early days as a superbike. the drum system must have thrown the industry on it's ear when new i expect.

nother brief question or two if i may. when did the concentrics come out across the board as it's got the later flange type inlet manifolds on it and a soon to be evicted pair of wal phillips 1" 3/16 injectors?

and on the points end of the magneto is a cap with a wire draped out of it. i'm assuming this is a kill switch type apparatus but the wire currently runs to nothing. is this to simply be earthed out through a switch dirt bike style as with a lack of valve lifter there'd be no quick "polite" way of otherwise shutting it down.

dumb question i assume but do engine parts come up in a classifieds section of MPH from time to time? a long shot i know but if someone had an irreclaimable bottom end with a salvable valve lifter it'd save me an ankle in years to come. luckily the bulk of the rest of the bike is all there though in varying states of kitsch. quite why anyone would have chromed that much of anything is well beyond my reckoning.

thank you all for your help and comments. theres another one at least in the region but as i don't know the owners i'd rather deal with those who utilise the net the same as i. the other forums i belong to for varied vehicles are generally a font of information and less straining than picking just one persons brain in person plus whatever is written up can be returned to for reference at will.
 

Tnecniv Edipar

Well Known and Active Forum User
Non-VOC Member
Parts are increasingly less frequent in MPH. Most stuff tends to go on ebay these days. Concentrics were introduced in the '60's.
 

lindie

Well Known and Active Forum User
Non-VOC Member
my apologies. brain is off somewhat at present due to the time. we may be a little ahead of you as for time zone.

had mean't the monobloc i'm afraid, not the concentric.
 
Top