E: Engine Valve Springs

[vibrac]

So far I am no further ahead, probably because I wasn't clear at the outset.

Where can I get decent valve springs for a street motor today that will just pop in without reinventing the whole valve train??

From anyone selling standard valve springs made to drawing. As to the interference between coils I understood that only occured once they were in tension on the valve and indeed was intensified as vibration set in and dissapated as they touched but what do I know I simply replace them on my racer every season since 1965 ain't dropped a valve ( yet )

 

[Robert Watson]

Thanks Vibrac, I understood that if there was no touching the valves could go into resonance and cause valve "bounce"

I have asked the VOCS to confirm what's what. We got a new set from them and there is 40 - 50 thou clearance betwixt inner and outer, it just surprised me that it was so, hence the questions.....

They are going to investigate.

 

[Gene Nehring]

Steve Hamel sells the RD springs for terry in North America. He may have some in stock. He also has run them in his engine rebuilds and has seat pressures at hand. I recently relayed that information to Nigel.

I believe they would be close to johns. I do have the exact numbers at home in Vancouver. He does recommend relieving the upper guide seat to reduce pressure for street bikes.

 

[Nigel Spaxman]

I have used the Terry Prince kit for two years now. At first they had way to much pressure and they wore out my cams. I then checked them and I think the seat pressure was about 125 lbs. I altered the top collars and I also had to relieve the insides of the valve caps that cover the valve springs. The seat pressure is still around 100 lbs which is a bit high. The pressure with the valve open is still rather high as well. I think that I would get new standard springs if I did it again. John was using rocker arms with a different ratio for more lift so he may have needed these springs with a bit higher pressure. My bike never floats it's valves anyway. I will look this winter and see how my cams are wearing now.

 

[davidd]

RD Springs is located in Hesperia, California.

Valve Train Parts For Motorcycles, Watersports, and Powersports | Rd Valve Springs

RD Valve Springs offers valve train parts for early and late model motorcycles, powersports, watersports, automotive and custom or one-off applications. RD Valve Springs uses the best quality material available and all products are designed and made in the USA.

www.rdvalvespring.com

I have sent them heads and they will set them up however you want them. They will sell the parts as far as I know.

David

 

[Deleted member 3831]

Patrick Godet's racing Grey Flash had the intake valve lifted more than 0.500". The valve springs were RD IRL1034, and the intake valve was titanium. During testing the engine was often run up to 9000 rpm, but for racing revs were limited to 8200 max.
These valve springs are also used by many Classic racers, including Manx Nortons, G50's and Gold Star BSA's

 

[Monkeypants]

John M told me that seat pressure on his Shadow was 120 at install.
My 1360 was set at 105. I checked it with Dan Smith's home built test rig as well as John's more sophisticated device.
Both gave the same number.
As mentioned elsewhere, the cams and followers looked perfect at 1500 miles. Now it has 5,000 on it, I might have another look.
I think it's OK as the magnetic drain plug is clean and tappet clearance hasn't changed.
Cam damage can occur with a low spring pressure that allows the valve train to lose contact with the cam then slam back down at high rpm.
I think this might occur more often than we realize. It would explain why one rider has all kinds of cam and follower wear while another rider with the same components does not.
2 or 3 hundred RPM can make quite a difference.
I used to see this on little Honda engines in the 60s&70s but didn't understand the cause at the time.

Glen

 

[Gene Nehring]

Patrick Godet's racing Grey Flash had the intake valve lifted more than 0.500". The valve springs were RD IRL1034, and the intake valve was titanium. During testing the engine was often run up to 9000 rpm, but for racing revs were limited to 8200 max.
These valve springs are also used by many Classic racers, including Manx Nortons, G50's and Gold Star BSA's

According to RD’s web site max lift is .500 for lightening and single.

 

[Deleted member 3831]

RD's recommendation is based on a max valve lift that brings the spring to a certain distance from coil
bind. Many engineers do not observe this recommendation, but work to closer coilbind clearances, and such was the case for the Godet Grey Flash