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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
Lifted the rear cylinder today, as I wanted to clean it out thoroughly after removing carbon from the piston. The piston has rubbed against the cylinder below the rings. The guy who bored them said he could not get them “straight”, but it is only under the piston rings he said.
Here is a pic of the JE Piston:
About 10.000 miles since big bore.
Last edited by OakMountainRider; Dec 16, 2025 at 04:53 PM.
You will need the right tools to set proper valve spring pressure.. Myself, I've always had them done by the proper machinist.. I don't have the tools to check and set pressures so I leave that to them.. Here's a quick video on the tools necessary and the knowledge to do so..
You will need the right tools to set proper valve spring pressure.. Myself, I've always had them done by the proper machinist.. I don't have the tools to check and set pressures so I leave that to them.. Here's a quick video on the tools necessary and the knowledge to do so..
Oki, I should not have mixed the stock springs up. So it is all about the pressure, not spring height? And then you aim for an even pressure on all the four springs at full lift?
Anyway, I found this method in the S&S manual. Think I will look closer on that and also get the measurement tool they use.
https://www.jpcycles.com/assets/0001/8858/510-0227_streetperform_585round_valvespring.pdf?srslti d=AfmBOorC30j3rsL8X04b7mP4kt28dK6SUWC0xO8vFldtcdDJ dVrRpjJr
Last edited by OakMountainRider; Dec 16, 2025 at 10:18 PM.
JMHO but the OP does not have to be concerned about pressure for his application. Set the springs up so all are installed at the same height; pressure, whatever it is, should be at or near the same for all four. Valve spring "micrometers" are not expensive, available on Amazon and make measuring installed height to determine if shimming is required accurate and simple. Shims are available in a variety of thickness and from a variety of sources. The S&S instruction sheet is a great resource to follow. Truth be told, the OP could measure the S&S springs, out of the box, to be sure they are all within a mm or two of each other in height, install them straight up with no negative issues. Having said that, being **** and having a severe case of "tinkeritus", I would take the time to measure to ensure all springs were installed at as near the exact same height as possible.
Measured free spring height, (manual says 59,1mm)
A/ 60.2 (0,3 mm too high)
B/ 60,1 (0,2 mm too high)
C/ 60,1 (0,2 mm too high)
D/ 61,1 (2 mm too high)
