Hello AMCA members. My question is this I have after market cylinders on my 1947 74 ci knucklehead and over time i found OEM 1947 74 ci cylinders that are nice condition. The thing about these cylinders is that the rear is stock bore and the front is 0.40 over bore so can these cylinders be cleaned up and used on my 47 knuck being they are mismatched cylinder bores.? Kenny.
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Yes you may run different bores. When a common crankpin Vtwin is balanced the first you thing you do is combine the reciperating weight (2 pistons plus the upper end of the rods) - the rotating assembling does not know that there are 2 separate piston assemblys because they are running on the same crankpin.Originally posted by kenny View Post
I do it all the time. No sense in wearing out cylinders in a machine shop.
This is going to cause arguments but....
Jerry -
And this lifted from another post.
"There is NO problem running two different sized pistons. You can run say a 20 in the front and a 60 in the rear -- the bike will not care".Comment
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When I first built my 44UL I found a n NOS front cylinder but could only find a .020os rear, been like that since the '70s...Robbie Knight Amca #2736Comment
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Kenny,
Here is something to consider and think about...
They share the same balance factor, crankpin, intake manifold, carburetor body, carburetor calibration, air intake filtration, ignition breaker point, ignition condenser and ignition coil.
Duke KlemanComment
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