THIS IS TRUE.... but mount that assemble between two completely out-of whack mountings and what do you get? Didn't the new Vicents do ok with their original balance factor?
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Balance Factor
- Thread starter Rob H
- Start date
Don't be a genius:
| [h=3]The bottom line is that the physics and mathematics involved in how the motor operates are far too complex to make a formula-based balance factor any more than a reasonable compromise. These are only the factors that I've personally detected; there are certainly more (of greater or lesser effect) than I am not capable of adequately describing, such as the elasticity of components, harmonic resonance, gyroscopic forces, precession, etc. Once the factor has been selected, the remaining tasks are accurately to record the component weights, and precisely adjust the flywheels to compensate. Your motor will last longer and be more pleasant to ride afterwards. My opinion: don’t try to be an innovator in selecting a balance factor; use one that has stood the test of time & experience, and has been successful in a motor very similar to yours (especially with regard to stroke & rod length, piston gram weight, operating RPM range, and compression ratio).[/h] |
Sid here . Uncrated mine myself , was first to start it on the spot . Ran nicely , smooth and strong . However it's known that there were variations in lack of unpleasant vibrations among Vincents , some shook more than others .
A convienant way to read runout is to slide the flywheel assembly back into its drive side main bearings , it will revolve very smoothly with good mains in its " home " so to speak . Mount a thou dial gauge rigidly so that a reading can be taken up close to the right side wheel and revolve the crank assembly . This will give a very close indication of how true the assembly is . And the vibration to be one might well expect . We got Gunga Din down to no more than a half thou total . Difficult job though .
A convienant way to read runout is to slide the flywheel assembly back into its drive side main bearings , it will revolve very smoothly with good mains in its " home " so to speak . Mount a thou dial gauge rigidly so that a reading can be taken up close to the right side wheel and revolve the crank assembly . This will give a very close indication of how true the assembly is . And the vibration to be one might well expect . We got Gunga Din down to no more than a half thou total . Difficult job though .
That's the whole point here: making everything as is should be..... by the way, anyone balance their clutch lately?
Sid here . Usually if there has been no shifting of the flywheels , ie loss of truth , the chance of there being main bearing problems is very rare because it is that very un planned movement that damages them and wallows out the alloy bores , causes them to migrate out of their bores inwards towards the wheels where so often they strike the crank pin nut . most often seen on the left or drive side . They are unable to withstand with the Maryln Monroe like hips movement the main shafts develop . Again just logic .
The bearings loose their fit no matter what. I have dissembled dozens of machines with true cranks and the outer bearing race machining a groove in the flywheel which was the only thing holding it in: the flywheel!
I never found this condition to my memory . It seemed to me that the shifted wheels came first .
As for clutch drums I never found them a balance problem tho I dragged with the Vincent clutch for years , turning to 7,500 rpm .
Very smooth if there was no detonation . Won a closet full of trophys . I used one of those lightened BL drums and also turned off every other rib beginning just after the first rib . I did dress all the edges of those backside releafs , especially the cuts that entered the inside friction surface , a very sharp change in direction there promoted stress . Never had a drum fail . Used a ball race thrust bearing in the outer pressure plate and a cut down VW inlet valve as a pusher . Totally reliable . Sid .
As for clutch drums I never found them a balance problem tho I dragged with the Vincent clutch for years , turning to 7,500 rpm .
Very smooth if there was no detonation . Won a closet full of trophys . I used one of those lightened BL drums and also turned off every other rib beginning just after the first rib . I did dress all the edges of those backside releafs , especially the cuts that entered the inside friction surface , a very sharp change in direction there promoted stress . Never had a drum fail . Used a ball race thrust bearing in the outer pressure plate and a cut down VW inlet valve as a pusher . Totally reliable . Sid .
Sid here . So extremely rare to strip a motor that HADENT shifted . Bill Jean says he has only gone ONE that hadent sheered or partially cut through the Mills pin . Only one in decades of working on Vincents . Might Rip comment upon this ? This indicates how prone they are to turning main shaft in wheel . The simple fact is that the steel chosen for the std. wheels is too soft to maintain its grip on the shafts , both main and crank pin . Much harder on Gunga Din . Had to be .
Nobody is saying a Vincent could not be made to go fast but that is not the issue here.... how long did it last is the issue. Main bearings were falling out in the fifties, main- shafts and pins were breaking lose in normal use from those silly putty flywheels in the fifties, and if you waited
around long enough long enough those ridiculous floating rocker retainers would eventually wear their way through the top of the head.... and what other machine needed a collection or over and under gears to assemble a timing chest? What other machine do you know of had drop-out main
bearings.... the ones that did have compression retained mains also had good alloy in the cases to keep them that way.
When you have a heavy fast revolving component like a clutch.... and it's out of balance.... what do you get? There's a good way to lesson vibration if some fellows clutch in in need of balance.
around long enough long enough those ridiculous floating rocker retainers would eventually wear their way through the top of the head.... and what other machine needed a collection or over and under gears to assemble a timing chest? What other machine do you know of had drop-out main
bearings.... the ones that did have compression retained mains also had good alloy in the cases to keep them that way.
When you have a heavy fast revolving component like a clutch.... and it's out of balance.... what do you get? There's a good way to lesson vibration if some fellows clutch in in need of balance.