How to tell HD valve springs?

[renobruce]

Is there a way to tell them from OEM?

[UncleMike]

Yeah, they'll be three times as expensive as OEM, they'll be chrome, and when installed, your bike will be twice as loud and half as fast as before.

Wait, HD doesn't stand for Harley-Davidson, does it?

[trippivot]

diameter of the wire is thicker and the coils are fewer to the same height

[Dogma]

diameter of the wire is thicker and the coils are fewer to the same height

Unfortunately you would need a stock spring to compare to. Anybody out there have a stock spring to measure?

[Steve]

Well, I have a worn-out spring that I took out of Freebie a few weeks ago.

It was noticeably shorter than the new OEM springs we put back in.

.

[rapidray]

Or, if you were like me, you could use your Rimac spring tester to check the spring's pressures at installed height. That will tell you how much stiffer one spring is from the other. If you aren't in a rush, send them all to me & I will check them all. It will take me about an hour if you have 4 or 5 sets. Then I could bag them & mark which were the best. Were you sending me money for something? If so, what was it, I don't remember? Ray.

[renobruce]

To explain further, I bought a head a couple of years ago for my Beast project that was already reworked...ported, 3-angle grind on the valves, new springs and seals. But I don't know if the springs that they used are heavy duty or not. It seems that they are required if you run anything but stock cams. I don't have anything to compare them to unless I take the head off of one of my spare engines, which I suppose I could do. But then again that would be a comparison to a used spring. Maybe I'll pop one of the new ones out and see if it compares to the specs in the manual (if there are specs on the valve springs).

[Nessism]

I have a pile of extra springs Bruce. Pull one out and post the specs, and then I'll do the same. Measure the OD of the spring, the OD of the wire, and count how many coils, including the ground down coils on the ends.

[renobruce]

I have a pile of extra springs Bruce. Pull one out and post the specs, and then I'll do the same. Measure the OD of the spring, the OD of the wire, and count how many coils, including the ground down coils on the ends.

Thanks, Ed. I'll pluck one out in the morning.

[renobruce]

OK, I took one of the valves out and here is the pic and the specs.

Inner spring:

free length: 34.85mm
diameter: 3.00mm
coils: 8

Outer spring:

free length: 42.95mm
diameter: 4.00mm
coils: 7

So in comparing these to the manual, the free length is less than the range, but above the service limit on both the inner and outer spring. But of course I have no idea what the free length is on an aftermarket H.D. spring.

[Nessism]

Those are stock springs Bruce. They measure the same as the ones I have.

[renobruce]

Thanks, Ed.

[Macmatic]

I was searching for some related info and didn't find it so in an effort to reduce thread sprawl I'm going to ask my question here.

I'm getting ready to do valve stem seals on my '83 GS750 and I'm using a spare head off a Canadian bike to do a dry run and work out a spring compressor. The first two springs I pulled out from #1 EXH measured 36.84mm free length and the limit spec in the manual is 38mm. Springs would get SHORTER not longer, right?

These could be out of limit short or maybe the Canadian bikes had different springs (unlikely I know) but I'm guessing these are short, being 1.16mm under size. Unless I'm all mixed up and they would grow somehow. I know this was a pretty low mileage engine but had an oiling problem or ran low on oil, scored #2 cylinder and shot cam follower on #1 & #2 exhaust. The cams have been in the head but with very loose caps for 4+ years. I don't know which were down and which were up or for how long before than.

/\/\ac