Emergency request.... Henderson Four Valve Spring Info

[sirhrmechanic]

Trying to help my friend get some last minute details sorted on his Henderson Four which will be on the Cannonball. The valve guides lunched themselves, probably due to some massive springs being fitted.

He had his builder do new guides and valves and the job is great. But we need to get some more original springs. The heavy springs are still in place and we think they will be a problem.

Can anyone supply me with specifications on the original springs? Free length? Wire Diameter? OD seems to be 1" ID seems to be .800 or so. Free length, I think, is supposed to be about 2"? But that's just an educated guess. Number of coils? Anyone have a LBS per inch compression number? The ones that were in there were at a free length of 2.25" and tested out to about 60 LBS for 3/4". My gut tells me that's way too much for a nice low revving old MC engine.

I can source virtually anything for valve springs... but I need to know what to order. We have another Henderson nearby and are working on borrowing a sample (original) spring from that to test. But maybe someone here has some numbers or specs.

Thanks in advance!

Cheers,

Sirhr

[kval]

Sirhr
contact Mark Hill in NY, he is the person for 4 cylinder work

[Tom Lovejoy]

also I believe Rob Olsen has them ready to go new. Check his web site, do a search for Hendersons it well come up, he has good stuff.

[Tom Lovejoy]

I just checked hendersonmotors.com is his site, did not see valve springs - but about every thing else. Might try Bill Klien too, I used to have his number - well look for it. Check the KJ web site, I am sure somebody there well be able to assist, good luck.

[sirhrmechanic]

Problem temporarily solved.

We got valve springs... they got overnighted... Not sure where the replacements came from, but they matched the 'originals' that were removed quite well. Looked much better than the springs that were in place and likely caused the first problems.

The main thing we ran into was that the new valves that were just put in (after the first ones were damaged along with their guides), were about .250" shorter than the ones that came out. This caused real problems with the 'over strong' springs that caused the problem in the first place (and were reinstalled). But even with the new and apparently-correct springs... the coils were so compressed on valve lift that the springs were verging on getting coil-bound. Since getting and fitting new valves were not an option on that short notice, we made up a set of eight "Drop" valve keepers that extended the spring further below the top of the tappet by a hair under .250", restoring the spring length.

This, unfortunately, makes it hard to adjust the valves... but we solved that by making custom feelers made out of feeler stock and trimmed/bent to fit in the hard-to-reach valve/tappet pad area.

The other thing we found on the new springs was that the end grinding to set the spring ends parallel was somewhat variable. I think this is probably ok on these lighter springs. But out-of-parallel valve springs can be really hard on an engine. Especially if they are stiff springs. So while we probably didn't *need* to, we made sure that the ends were ground perfectly parallel, grinding the spring ends wet to keep them cool. We got them within a few thousandths of parallel and when the springs are installed, the keepers are very straight.

BTW, having the valve spring ends ground parallel is especially important on valves that are secured with a cross-pin or cross bar. Unlike the more modern collet-type keepers, the cross bars/pins allow the valve to get 'kicked' to whatever side the spring wants to send it as the pin can act as a fulcrum or a toggle. This side pressure on the valve stem causes rapid wear on the guide and quickly messes up the seating of the valve as well. In the case of this bike, the brand new valves were wrecked in under 500 miles by springs that pushed the valves hard to one side. Careful when choosing and fitting new valve springs! Even the best quality parts don't always just 'drop in.'

If anyone is interested, I'll post some pictures... When the bike gets back from the Cannonball!

Cheers,

Sirhr