Author Topic: crank lightening and balancing  (Read 5213 times)

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Offline the technological J

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crank lightening and balancing
« on: April 27, 2012, 08:47:03 PM »
is it possible to do this yourself(correctly)? i didnt know if there was some kind of method to do this at home or not?  with minimal tools nothing specialty
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Offline Retro Rocket

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Re: crank lightening and balancing
« Reply #1 on: April 27, 2012, 09:35:08 PM »
Thew answer is NO, this is fairly specialized work and should be done by an expert like Big Jay at APE or Ken at CycleX... ;)
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Offline mec

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Re: crank lightening and balancing
« Reply #2 on: April 27, 2012, 11:11:05 PM »
the answer is YES :)

lightening can be done by lathe and mill.
balancing is another thing. but when i look at some modeller forums, where people are building machines to balance their turbine mainshafts, i am sure this can be done with our cranks too.

mec
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Offline Big Jay

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Re: crank lightening and balancing
« Reply #3 on: April 27, 2012, 11:46:16 PM »
You can not static balance a crankshaft like you would a wheel. It has to be dynamically balanced, in an"X plane" thru the crank. You can not do this at home.


Offline voxonda

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Re: crank lightening and balancing
« Reply #4 on: April 28, 2012, 12:56:32 AM »
+1 on mec:




Lightening is not the problem, but like Jay says, it is in the balancing.
Better sorry for failing then for the lack of trying.

Offline brandEn

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Re: crank lightening and balancing
« Reply #5 on: April 28, 2012, 05:58:54 AM »
hey Rob, do you remove those staked balls to clean the oil gallery?

Offline Jim F

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Re: crank lightening and balancing
« Reply #6 on: April 28, 2012, 07:46:39 AM »
and there are other means of lightening a crank
you can go to the knife edge like Jay at APE for the most
or you can go a little like mine for my turbo build.
Mine has been lightened, balanced, and nitrided
the oil passage balls have been removed
these are tapped for a 1/4-20 set screw and will use red lock tight
when its ready for assembly
Brian livingood from Livingood Motorsports in Lawrenceville Ga builds road-race motors and he sent this crank out





good luck and I am with Jay and the others about not trying this at home

Jim
« Last Edit: April 28, 2012, 07:48:41 AM by Jim F »
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Offline the technological J

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Re: crank lightening and balancing
« Reply #7 on: April 28, 2012, 07:56:48 AM »
ive been reading up and whats the point of these ball bearings if the can be removed?
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
78 750K... http://forums.sohc4.net/index.php?topic=60257.0 (Omega)sold to fund the K4
94 ST1100..Gone
72 750 K2 Stay tuned!

Offline Sam Green Racing

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Re: crank lightening and balancing
« Reply #8 on: April 28, 2012, 08:41:38 AM »
Techno J, take no notice of this lot, it's quite easy. I did it to my little 175 twin years ago with nothing more than a hack saw and file to remove the surplus and a couple of digital bathroom scales to ballance it.
I put the bike over the measured flying kilometer at 156mph, well over the world record.
The motor was as smooth as silk and reved way above its previous best of 1400rpm and peaked at 1800rpm. 8)
When I shut it down, there was a loud explosion, I thought the nitro had caused it to hydraulic.
The crank some how blew out of the motor side ways and was never found. :(
A few days later I received a letter from a ladies lawer demanding compensation for the damage to the roof of her house 3 miles away. :'(
Seems the crank with 2 bits of con rods struck a glancing blow to her roof then vanished without trace. :-\
A month later, I received letters from the European Space Agency and NASA wantng to know what the hell I had put into orbit around Pluto and would I like a Job with them.
I told them it was just my crankshaft and it was just an accident.
Three days later I got a letter from the International Space Agency demanding £59 billion for damages to the solar panels on the International Space station which the crank had clipped on its way out of the Earths orbit.
Although it can be done with few tools, I  would leave it to the likes of Jay at APE.
If anything goes wrong like it did for me, you can at least blame it on Jay. ::)
One thing to bare in mind though, they don't call him BIG JAY for nothing. ;D ;D ;D ;D ;D ;D

Sam. :-X
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Offline Pecantree

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Re: crank lightening and balancing
« Reply #9 on: April 28, 2012, 11:06:50 AM »
Sam:
You really hooked me. :o
Steve
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Offline the technological J

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Re: crank lightening and balancing
« Reply #10 on: April 28, 2012, 01:10:06 PM »
you have some bad luck sam....  i think i might contact some one when i decide to get it done.... is lightening a crank a standard thing? or is some thing that one person can do better than another? like will honda man do the same work as jay as ken will at cyclex?
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
78 750K... http://forums.sohc4.net/index.php?topic=60257.0 (Omega)sold to fund the K4
94 ST1100..Gone
72 750 K2 Stay tuned!

Offline MRieck

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Re: crank lightening and balancing
« Reply #11 on: April 28, 2012, 05:57:01 PM »
ive been reading up and whats the point of these ball bearings if the can be removed?
To seal off the passages. I have seen those balls leak too under 100lbs of air. Another reason to replace them with the "grub" screw.
« Last Edit: April 28, 2012, 06:56:41 PM by MRieck »
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Offline voxonda

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Re: crank lightening and balancing
« Reply #12 on: April 30, 2012, 02:22:24 AM »
hey Rob, do you remove those staked balls to clean the oil gallery?

Yes, I did. Picture is taken just after turning the crank. After that removed the balls cleaned all up and sealed the passages.

rob
Better sorry for failing then for the lack of trying.