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Discussion Starter · #1 ·
I have a 1971 BSA Lightning 650 that I'm getting back on the road in a coupe of months and I want to get the rotator assembly balanced and blueprinted. Now anyone in the know knows that these are vibrating sons-a-bitches due to the fact that the motors are solid mounted to the frame and I want to cut down on that as much ass possible!

What I need to find out is who can get me the ROTATING & RECIPRICATING percentages for the crank? Another question is- Is there a way to fine-tune these percentages to make it more highway freindly? Its an awesome bike and I really want it back on the road but enough is enough

And anyone who gives me shit for not dealing with it obviously hasn't ridden their girlfreinds gas powered dildo down the highway for any given leangth of time!
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well i have'nt ridden my girlfriends dildo but have rode the shit out of my bsa and yes it vibrates a little at higher rpms

more important then balancing the crank is doing the needle bearing conversion in my opinion with this done and geared properly it would make for a much smoother ride

not saying balancings bad just that the conversions more important in my book
plus it will make for a longer lasting motor

i'm not sure what you mean by ROTATING & RECIPRICATING percentages for the crank?
it rotates 360 degrees and if its reciprocating somethings wrong usually the spacers used on the bushed side of the crank get worn and then beat into submission and the crank slams back and forth untill it finally goes kaboom
 

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1st I'm not a machinist. Nor an expert.

Maybe you're looking for a balance factor?

Most rigid mounted Brit engines have a balance factor of 75-85%. You will never get rid of the vibration completely, but it will move up or down in the rpm range as you change the balance factor.

Matching component weight from side to side is just as important IMO. Try to get the piston and rod assemblies from each side to match as close as possible.
 

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Discussion Starter · #4 ·
The %'s are what a machinest uses to find the smoothest ride and they can while dynamic balancing. They fine-tune the %'s as compared to the RPM's to make the bike ride better under highway use as compared to stop-n-go riding! Yes this might just stay a little bar hopper but you need to get on the highway every now and then! I would just like to find the %'s so when I take it over to the machine shop, I'm not paying for hours of trial and error

Does anyone know where I can find the stock percentages at least?

christian
 

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Discussion Starter · #5 ·
VA Rebel said:
1st I'm not a machinist. Nor an expert.

Maybe you're looking for a balance factor?

Most rigid mounted Brit engines have a balance factor of 75-85%. You will never get rid of the vibration completely, but it will move up or down in the rpm range as you change the balance factor.

Matching component weight from side to side is just as important IMO. Try to get the piston and rod assemblies from each side to match as close as possible.
The machinest Im taking it to has done tons of Triumps and Nortons but not to many BSA's and he said that the %';s are all different. I found on another site where a guy put his at 70% and said it worked a lot better than before. Im just wondering if there is a precise number to aim for!
 

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come on ******.....you did'nt havta tell on me did ya?
now what little rep i had left is gone, all gone, now what will i do?
fucker;)
****** said:
must..resist.......must...resist.......must.....

fugit

that aint what i heard

:D
 

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i'm a slight confused i guess
are you talkin how close to 100% balanced you can get it?
meaning that with a bsa bottom end you can only come as close as 75% to 80% balanced?

i to am in no way a machinist
i think i understand what you meant now atleast

still not sure what ROTATING & RECIPRICATING percentages for the crank?
and how you would fine tune them?

if the crank ass. can be balanced to 85% would'nt mean thats about all your gonna get?
 

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use some sort of damper?? and I would think when it's being B&B that the machiest would figure all that out ,would he not? Or I could be totally missing the point
 
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