Primary Drive Compensators

[Donkey Hotey]

I figured we should take this discussion out of Rich's thread and start its own topic. For some reason, I can't reply to Mike's request for help on the thread he started.

The issue is: there are no replacement primary drive compensator driven side ramps available. Depending on whether you have an early or late engine, the part in question is #4 or 15 on PDF page 72 (marked page 70) in the parts manual.

Mike Seastrom: can you post pictures of the damage to yours? Did you get the damaged one with the bike to take to somebody to be reverse engineered?

As was suggested: wire EDM could be used to cut the drive splines. The only problem with EDM is it's a slow process and--therefore--generally expensive. Just forewarning.

The rest of the machining would be fairly pedestrian. It could be easily machined on a CNC mill. Heat treating and material selection would be a large chunk of the work but, pales in comparison to the difficulty of getting the splines cut.

Again: if the original manufacturer can be located, that broach is probably a standard for them or they still have it on the shelf.

For those not familiar with the broaching process, this is generally what it would look like in production. A progressive cutting tool (the broach) has teeth that cut a little more as each passes through the part. the part starts with the basic inside diameter, then the progressive broach is pushed or pulled through the part.

https://youtu.be/vSmxi2224dc

[wytfut]

Mike does not have either piece, as I sold him the DWS without the ramps.... Which he knew when purchasing.
At the time he had a lead on an X, in a junk yard in his area (Dallas/Ft Worth). Turns out it was an early X, so the parts didn't work.
We used the ramps to put in Blue as at the time. The ones that were in Blue are being checked out with some machine shops.
Mike is only interested in one of the two pieces, as Jamie/Marty have 14 of the matching pair. Initially we were going to have both pieces made (and down the road we may have to).
Mike has been posting on a wide base.... Including the facebook site.
Jim Mccarthy, who I believe still works in R and D at Daimler, also stated that it should be an easy built via CNC.

If we don't have any luck with the machine shops up here in NebraXi.... I'll send the pieces to Mike, and he'll give it a shot down there...
Mike is in the process of organizing his projects for the winter, thus the parts request. Get a chance, get on facebook, and search Marv's garage. Mikes shop is a dandy....

Bruce

[franknsr]

..."X, in a junk yard in his area (Dallas/Ft Worth)..."

wHaT?! Where? I must buy it.

[blackheart]

I'd think wire EDM would be competetive to have a broach cut.  Are the splines involute or straight sided?  If involute they would likely be generated and not broached.  I may be way off here as Ive never seen such an operation, however with internal gears Im sure some are generated for better accuracy.  But this would only be for high accuracy production type parts operation.

[Donkey Hotey]

For a first article, EDM and broach will probably be similar but, after that, the broach will win the cost war.

Are we sure that these compensators were not cut by the same company doing the Harley parts? I realize the Harley compensator drives a chain instead of a gear but, it would not surprise me at all if they came from the same company.

This is a Harley Dyna compensator pic, lifted from Ebay:

[franknsr]

A couple thoughts on this;
First, a few years ago I needed to replace an obsolete rear sprocket and hub assembly on a bike and the only option was to ship the assembly to a shop who cut the old sprocket off and welded a new one in place. If they can do that with enough accuracy to make it true, I would think they could cut the ring gear off an old compensator and weld it to a replacement (HD?) part.

Second; would it be possible to cast one of these missing parts out of iron rather than machining it? Or would that make it too brittle for the application?

Just throwing ideas out there....

[Donkey Hotey]

The Harley ones appear to be cast steel, that gets post machined. Until we see the actual EH parts, I can only assume they're similar.

[wytfut]

have 2 shops checking out how to build these compensators....
the one shop (builds guns) will cut them out, and then send to another shop to cut gears...
Second shop is going to contact a motorcycle drag race builder for information, if there could be other things to know...
both shops want to build out of hardened SS....
cost would be around  800$ at a batch of 100...   all estimate...
maybe what we actually need to do eventually.... but 800$ is going to be expensive....

[blackheart]

I'll try to do a PMI on the one that I took out of my 08 FLTR.

That ramp and sprocket look like an investment casting then sprocket is finished machine.  FYI, investment castings can be pretty good stuff, cast out of such alloy as 8620.  Comp cams for years has cast rockers this way.  It could also be powered metallurgy which is also very good as they are post forged to get density (voids out) up.  Modern automobile connecting rods are made this way.

They wouldn't make of stainless.  Unless it is a precipitation hardening stainless, such as 17-4PH, austenitic stainless steels cannot be hardened, they are soft and strengths are low.  They can be work hardened but not heat treated to make hard.

I'd bet my life they are made of some ferritic steel, alloy of course.

[blackheart]

So I followed up this Monday and took a compesator assembly off an 08 HD TC96 & shot it for nominal alloy composition.  All three pieces came back as 8620 or some close cousin such as 8740.  This is a classic gear and shaft alloy.  I dont know the carbon content so it could be a higher carbon alloy which would not require carburizing to develop case harness upon a typical heat treatment.

Whats interesting is this compensator had 95000 miles on it and really only needed the spring pack shimmed as they had lost their preload.  The ramps looked perfect.