Board index Flathead Power-Technical Questions, Answers, and Suggestions Morthodites-"Non Factory" heavy duty valve springs

heavy duty valve springs

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Post Mon Sep 29, 2008 3:16 am

Posts: 48
Just found KHK cams for my WL+K topend project. Originally planned to run KH cams and standard valve springs. Now probably need stronger springs to keep valves from floating and/or locking the springs. Can somebody give me a source and partnumbers ? Found references to using Chevy springs, the inner set from a double spring setup. Any tips? Thx PJ

Post Mon Sep 29, 2008 7:23 am

Posts: 131
Location: BRANFORD, CT

Hi P,

I looked at your pictures and think you are using single WL springs, WR tappet guides, and spring covers?
Steve Hartley, 37ULH on this forum is making single valve springs for the WL/WR that allow use of very high lift cams without coil bind, and have seat and open pressures which are similar to the dual KR springs. Most of the WR road racers in the US are using these springs with roller cams.
I have personaly measured the pressures and deflections on these springs along with the dual KR springs, and some WR springs which were made by S&S for Fred Pettis.

Email me and I can send you PDF's of my results.


Also the dual KR springs are the same as used on the Sprints, While these are unavailable. R&D Spring in Calif. makes replacements and I believe they are the same as used on 650/750 Triumphs.
Bruce Argetsinger
AHRMA Dirt Track # 67J

Post Tue Sep 30, 2008 2:10 am

Posts: 48
Thanks Bruce, Just the info I need. I'll contact 37ULH. I am very interested in your measurements, so... check your mail.

Post Tue Sep 30, 2008 2:26 am

Posts: 48
By the way I just received a message from Leineweber stating that using WR tappet guides will not line up with the K-topend valve stems and that it will wear out the cams. It has been discussed a couple of years ago here on FHP-TT. I did some measurements then on the KH cams and there proved to be a very slight difference in angles between documented WR angles. But we also know that Frankenstein has been running such a setup (WL+KH topend) for a long time without big problems. So... I guess I should just try and see what happens. In the meantime I think we should avoid the impression that it is a perfect fitting solution (WL + K topend + WR tappet guides) because it is not.


Post Tue Sep 30, 2008 10:02 am

Posts: 591
Location: Crewe, Great Britain

Hi, Piet Jan,

The KK and KHK from the factory only used single springs. I never found valve float on mine fitted as that. They are slightly shimmed, but not to the Nth degree!!! These are the springs that were on the bike when I bought it in 1987... But my valves are to KR race specs and much much lighter than std ones.

The KR double springs were originated from Tom Sifton experiments in 54, he used Triumph double springs in that year. The set up was passed on to H-D, so the specs of the H-D KR springs after that can't be far from the Triumph set up... A friend of mine is trying that on a WL/KH, he sourced some Austin Mini Cooper race springs that are very near the right spec and dead cheap... Can't say how it works, he hasn't started it yet!!!


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