Crank Balancing

[ausy300pro]

does anyone know where i can get a (pro) crank blanced and has anyone had one done, was it a worthwhile exercise.

thanks for any help.

p.s. contact in yorks preferably

Edited November 1, 2005 by ausy300pro

[ask greeves]

On a one cylinder engine, the balance factor is built in at the factory, if you wanted to change the balance factor, by drilling crank and fitting either lead, heavy metal or expleted urainium thereby altering the counter weight opposite the reciprocating parts, then your knowledge or that of your balancer on recipricating factors, must be at the cutting edge of technology. Best bet would be just to make sure crankshaft is true and that the crankpin is intact.

[zanx]

Chris Appleby are numero uno crank balancers, they can balance stuff that no one else will touch.

[kevin j]

what is your goal?

If it is to run totally smooth, can't happen in a one cylidner engine. Theoretically, anything less than 6 cylinders can't be balanced, but 90 degree V twins, 90d V4, and inlne 4 are pretty close, except for some higher frequency second order vibrations.

As greeves noted, the balance factor just defines how much of the piston is counterweighted on the crank. If the piston weight is addded to crank, it becomes 100% balanced in the vertical direction (piston goes up, crank weight goes down), but now totally out of balance front to rear (counterweight going front to rear but no piston motion in that direction). So the balance factor just is some arbitrary point of the lesser of two evils, determineed by frame reactions, and how it feels to the riders. some compromise feels the best, so it may be worth doing especially to make sure its true in line. Just have realistic expectations for what you are getting.

every one knows someone, whose brother in law heard of someone who had a neighbor with a Triumph/Harley/Ducati he could balance a nickel on the crankcase. Must be the same never found place the 250 mpg carburetors are stored.

k

[steve shakeshaft]

Don't bother. You cannot balance a single cylinder engine.

[charliechitlins]

My Harleys are always balanced within a gram.

They still ride like a lawn tractor with a broken blade.

[steve shakeshaft]

All you can acheive with a single is changing the % balance factor from stock. If the factory got it right, there's no reason to change it. Using a significantly lighter or heavier piston may justify rebalancing but that's about it. HTH.

[steve shakeshaft]

My Harleys are always balanced within a gram.

They still ride like a lawn tractor with a broken blade.

<{POST_SNAPBACK}>

Balanced "within a gram" of what exactly?

[charliechitlins]

Well...it depends on the balance factor, which, to a certain degree, is a matter of preference.

But what I mean by 'to the gram' is that everything is weighed, right down to the wristpin clips, then material is either removed or added to the flywheels.

[steve shakeshaft]

Ahh, yes I see. Excellent approach.

[ask greeves]

Bell Crash Helmets had a wonderful advert several years ago "If you've got a ten dollar head.....Wear a ten dollar helmet"

[ausy300pro]

I think everyone has missed the point a little what I initially meant was is the balancing as done at the factory consistently right, I.E. is every set of flywheels, con-rods etc balanced for the engine it will be used in, there seems to be big differences in how smooth the gas gas engines run some of them are like sewing machines and others like gold stars. p.s. I know the smaller engines are inherently smoother, there are differences (noticeable) in same capacity engines, or is it possible this is down to runout rather than balance.

Edited December 3, 2005 by ausy300pro

[charliechitlins]

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