'41-'52 45 Clutch Rebuild - Choosing parts

[Rex]

1. The Hub
Which would be best to put on a new aftermarket clutch gear, NOS or after market? I've seen forum threads about new hubs that are too loose, and some that are too tight. I'm willing to do the fitting work on a tight one.

2. The Bearings
It looks like the Big Fix setup is the way to go.

3. Friction Disks
OEM type riveted to steel, or bonded to aluminum?

4. Steel Disks
I noticed after @ 150 miles that the friction and steel disks weren't making compete contact. Some showed contact around the inside surfaces, and some around the outside. Will having all new friction and steel disks provide more complete mating, or is that as good as it gets?

Rex

[Paps]

1. The Hub
Which would be best to put on a new aftermarket clutch gear, NOS or after market? I've seen forum threads about new hubs that are too loose, and some that are too tight. I'm willing to do the fitting work on a tight one.

2. The Bearings
It looks like the Big Fix setup is the way to go.

3. Friction Disks
OEM type riveted to steel, or bonded to aluminum?

4. Steel Disks
I noticed after @ 150 miles that the friction and steel disks weren't making compete contact. Some showed contact around the inside surfaces, and some around the outside. Will having all new friction and steel disks provide more complete mating, or is that as good as it gets?

______________________________________________

HUB........NOS unless you wish to measure a bunch of aftermarket ones to get a tight one.

BEARINGS....big fix as long as the fitment clearances are loose enough to allow free release play. Big fix gives better surface contact.

FRICTION DISCS....OEM Type. Steel moves around less when hot.

STEEL DISCS.....try Kurts diaphram clutch. It provides equal presure all along the surfaces. Slight mods needed to nut but nothing major for installation.

Just My Opinon... Paps

[schmittm]

Rex,

Paps is right on the money on everything he suggested.

I have a big fix setup in 3 bikes now and could not be happier, a lot smoother and quieter than those 60 loose balls floating around in the big cheese grater!

Paps suggested one of Kurt's diaphragm clutches, I've never tried one. If you stick with the stock setup make sure all the old springs have the same free length, or consider a set of new ones. Make sure that all the cover bolts are drawn down evenly and that the dowel pins and studs are straight so that the cover does not bind when moving in and out.

also remember that the steel plates are "sided", they have an inside and an outside and must be installed facing the right direction.

good luck

mike

[Rex]

Paps & schmittm -

Thanks for the advice. I've had the current clutch apart a few times and did see the "OUT" designation on the steel disks. The diaphragm spring does look like a better way, but since this is a period modified open primary machine, it's getting a set of new springs.

When I rebuilt my wheel hubs, I bought several different sizes of rollers to obtain the right running fit. Does the same method apply to fitting these bearings? I haven't seen any offerings of bearings +/- .0001" to arrive at the right size. If they are too tight, does the hub, shell, or both get lapped?

[schmittm]

Rex,
I wondered that myself when I installed the first big fix kit. Apparantly they are "one size fits all". Like I said, I've put in 3 of them now on hubs and drums that were well used, I've never installed a set on NOS or aftermarket new hub and drum combinations. I gave them the old "shake test" after installation to see how much play there was between the hub and drum and all 3 of them had considerably less than the balls but all 3 rotated freely and smoothly with no binding. No problems yet with any of them, one is a daily rider and has a bunch of miles on the set up.

Just for the record, I installed 2 sets with high-temp bearing grease and one with Lubriplate, can't tell any difference.

keep us posted...

mike

[Rex]

45 Clutch Hub Installation

How is the interference fit accomplished when installing the clutch hub to the transmission shaft? I don't want to hit it, but would rather push it on with the hub nut.

What is the correct torque value for this nut?

Is there a measurement I can take that will confirm that it's on as far as it should be?

Rex

[schmittm]

Rex,

I know a lot of precision mechanics will probably tear me up for what I'm about to say, but this is my story and I'm sticking with it.

1. Make sure both the surfaces are absolutely clean and dry, the shaft and the hub.

2. Slip everything on and start the nut. (here comes the non-traditional part) Set your air impact to a lower setting, I use #2 on my snap-on, and run the nut down tight, give it a few extra brrrrps just for luck. I don't have one of those fancy factory tools for holding the hub anyway, so a torque wrench wouldn't be of much use to me.

3. Check the alignment between the motor sprocket and the hub sprocket, if everything lines up you're all set, lock it down and you're done.

I've never had one come loose or fall off or give me any trouble. I check for play whenever I go in to adjust the clutch or check primary chain adjustment.

Now I'll go hide, I'm sure somebody will have something to say about this method. Cotten?

[Rex]

Another Dark Day...

I went to fit my n.o.s. clutch hub to my new reproduction clutch gear splines (with @200 35mph break-in miles), only to find that it falls on easier than the old hub.

I can wobble the old hub on and off, but the new one just slides
all the way on without any effort.

The clutch gear splines have no visible damage, the old one was beaten to death.

Think a new n.o.s clutch gear is the answer?

Don't know what to do if the new oem hub falls on to the new oem clutch gear.

Rex

[schmittm]

OK Rex, you got me curious enough to go out to the shop and pull out a few boxes in the "Transmission Department"

I came up with:
1. a new clutch gear (not sure of its origin but I suspect reproduction)
2. an old clutch gear, OEM, still very serviceable
3. a new hub, this one I'm sure is a repop new production
4. an old hub, used, OEM, still very serviceable
5. a complete transmission that I pulled from one of my bikes

I then started to mix and match, trying all the various combinations. Every combination was a "slip fit", I was able to insert the clutch gears completely into the hubs without any force (no hammers were involved). Placing the hubs on their studs on the bench the clutch gears would drop by their own weight all the way to the shoulder. It did seem to make a slight difference when rotating the gear so that a different set of splines engaged, some positions were tighter than others. When fully engaged there was a very slight side-to-side play detectable in every combinatin but not enough to concern me.

The one thing worth noting is that the loosest fit was with the new parts, when the new clutch gear was inserted into the repop hub it dropped in with a clunk. The tightest fit was the old hub on the complete transmission assembly, I had to "wobble" that one on but it still seated with only hand pressure.

You should be just fine with what you have as long as the the hub goes all the way on the clutch gear splines and bottoms out on the shoulder on the clutch gear. Make sure the nut is TIGHT, like I mentioned I use an air impact, and lock it securely with the "u-bend-it" locking ring.

good luck!

mike

[Rex]

Clutch Hub Clearances

Mike-

Thanks for the research and reply. It may save me the money buying a new clutch gear just to find out that it won't give me any better result than I have now.
I don't want to go all the way through that transmission again if I don't have to.

The Numbers

I've found the average clearances between the new hub and gear spline surfaces to be @ .005". A LONG way from an interference fit.

Another disappointment was the fit of the roller bearing kit. It's @ .003" (.0015" per side, new hub & old shell), and not much less wobble than the fit with the caged ball bearings. And a plastic retainer. I was hoping for a fit similar to the wheel hubs and axles.

So far, $240 for no improvement.

[schmittm]

Rex,

I don't blame you a bit for not wanting to go back inside that tranny. If my memory serves me, there are something like 104 uncaged roller bearings inside that thing, in various different diameters and lengths. If the splines and threads are good on the clutch gear that's in it you should be alright.

I rode a WL to high school, and anywhere else it would take me, back in the 60's, and I've been accumulating them ever since. I have taken lots of them apart over the years but I don't recall ever seeing clutch gear splines or hub splines beat up to the point where they weren't usable.

The hub nut, on the other hand, is a different story. Very few shade tree mechanics (or high school kids in the 60's) had one of those special factory tools for the hub nut. Every one I've ever taken apart has had a chisel on it at some time in its life, to either tighten it or loosen it. I suspect that more damage has been done to those trannies with a hammer and chisel than any other cause with the exception of running them without oil.