4" Pistons for 4 5/8" Stroke Crank?
#1
11-12-2012, 08:40 AM
#2
11-12-2012, 12:35 PM
In either case, the MoCo offers a high compression forged piston (PN 22503-07A) that would work with the 4.375" crank if your friend is still running the CVO heads. The only pistons the MoCo offers for the 4.625" crank are 4.060" bore.
If you truly are looking for a 4" +.010" OS piston for the 4.625" stroke, you can have custom pistons made. CP will make them but they are expensive and they used to only make custom sets in pairs. Randy at King of Cubes may also be able to help.
#3
11-12-2012, 02:22 PM
Just to clarify, the CVO engine is 110" which would be 4.00" x 4.375". So, is you friend looking to build a 117" by replacing the 4.375" crank with the 4.625" crank. Or is you friend just looking for a .010" OS piston for the 4.375" crank?
In either case, the MoCo offers a high compression forged piston (PN 22503-07A) that would work with the 4.375" crank if your friend is still running the CVO heads. The only pistons the MoCo offers for the 4.625" crank are 4.060" bore.
If you truly are looking for a 4" +.010" OS piston for the 4.625" stroke, you can have custom pistons made. CP will make them but they are expensive and they used to only make custom sets in pairs. Randy at King of Cubes may also be able to help.
In either case, the MoCo offers a high compression forged piston (PN 22503-07A) that would work with the 4.375" crank if your friend is still running the CVO heads. The only pistons the MoCo offers for the 4.625" crank are 4.060" bore.
If you truly are looking for a 4" +.010" OS piston for the 4.625" stroke, you can have custom pistons made. CP will make them but they are expensive and they used to only make custom sets in pairs. Randy at King of Cubes may also be able to help.
I'll have him call CP and/or KoC.
Thanks!
#4
11-12-2012, 04:57 PM
You might consider asking Randy about possibly boring the 4 inchers out to 4.060 The 120 pistons are actually priced quite reasonably, not sure it can be done at all but you would have to address piston to case clearance and piston to piston clearance at bdc, you will also need the SE piston jets with that crank. I would suggest he just buy the 4.060 setup, bore the cases and be done with it. They have a much longer spigot and control the piston better at bdc. He can recoup some cost by selling the 4 inchers.
Last edited by BVBOB; 11-12-2012 at 05:03 PM.
#5
11-12-2012, 08:06 PM
Good advice on the 4.060" and the deeper spigot which will help stabilize the cylinder with that long stroke. The 4.060" cylinders are the 120R cylinders fro a reason. I think I would stick with the 4.375" crank and 110" and look for more power with headwork and cams. Or do what BVBOB has suggested. Nothing worse than spending a bunch of money on a project only to have it turn into the project from hell.
#6
11-13-2012, 06:29 AM
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HILLSIDE MOTORCYCLE & MACHINE, INC.
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HILLSIDE MOTORCYCLE & MACHINE, INC.
HARLEY-DAVIDSON SPEED & SERVICE CENTER
5225 SOUTH MAIN ST., MUNNSVILLE, N.Y. 13409
Sales/Support 315-495-6650
www.hillsidecycle.com
Walk-in Retail Showroom
Complete H-D Machine Shop
Case & cylinder boring
Complete Cylinder Head Shop
High-Performance Engine Kits
Crank Rebuilding
Direct Link & PowerVision Tuning
Goodson HD Tooling Manufacturer
Maxton Mile World Record
4500 sq ft. facility
OVER 35 YEARS OF H-D ENGINE BUILDING.
See us on Facebook.
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