Topic: Speedo gear box retainers 750

[Jerry Rxman Griffin aka MuthaF'er]

I was surprised to find there are different part numbers for different years. What are the differences?

I'm looking for one for my front Lester wheel. I just realized the gear mechanism spins around LOL. Anyone have one they'd like to part with? I'm going to assume it's the later one, 76/77/78 K, 75/76F, A's, and the 550's. The reason I'm only assuming this is my rear Lester is for the disc brake therefore IT is the later model but that doesn't mean the front is also but probably?   

[scottly]

Are you talking about the thin, chrome-plated part that locks the drive plate to the hub?
 

[Jerry Rxman Griffin aka MuthaF'er]

No, it's the part inside with the flare. It has the 2 'wings' that fit inside those 2 indents on the chrome cover you are referencing. Can't figure out how to copy and insert the fiche image? It's item #8 on the front wheel parts page. Guess I need to remove the wheel in order to give you a better description word 'picture'.

[Rookster]

Some of them were 1 piece and others were 2 piece with a rubber grommet or some type of glue holding it together.  I'm not sure which one is earlier and which one is later.  All I know is that I put one of them in a cup of lacquer thinner to get the grease off it and it came out in 2 pieces.  I assume at some point Honda had a problem with binding in the speedometer gearbox which could potentially spin the entire assembly with the wheel and cause all kinds of trouble.  The 2 piece ones would just spin the part connected to the rim and the part connected to the gearbox would remain stationary.  That's the only real reason I can think of to make it 2 separate pieces.

Scott

[scottly]

I call it the drive plate. The earlier version engaged flats on the hub, and the later version had the "wings". Are you going to use dual discs?

[Jerry Rxman Griffin aka MuthaF'er]

OK guys, we're all on the same page now.

Here's my situation. The gearbox on my Lester wheel spins/rotates freely and it DOES have the/a 'gearbox retainer' (as referred to in the parts book) which Scottly refers to as the drive plate. Which one I do not know. I assumed it did not since the gear box spins/rotates freely on this bike as put together. I loosened the bolts and slid the chrome cover out slightly without removing the wheel to find it. The gearbox on my other F which has the stock wheel is locked in place and does not rotate.

I, once again, ASSUME the gearbox is NOT supposed to rotate??

This brings me to the next questiom - what locks the gearbox in place to keep it from rotating? The 'retainer' spins with the wheel and turns the gear box.

Do we assume mine is the one piece and perhaps I need a 2 piece one of which one piece keeps the gear box stationary while the other piece spins the gear? Trying not to tear apart the front wheel unnecessarily. Is it OBVIOUS that one of these is a 2 piece and the other a single piece? I often times need obvious LOL.

Single disc.

Scott,

What year is your bike? The part number for mine (75 CB750F) 44641-375-000 is for later models mainly 75/76 F, 76 - 78 K, and 550's but NOT for F2/F3's. The gearbox number is specific for these also.

Guess I need to drop the wheel and compare my spare gearbox with what's on the bike since there are different parts numbers for those also.

[scottly]

The center of the gear box has a steel spacer cast into it. When the axle nut is tightened, the box is pinched between the head of the axle and the inner bearing race, locking it to the axle.
The one pictured is from a K7, and is two piece. I have seen a one piece with wings from a 550, and they appeared to be interchangeable.

[Jerry Rxman Griffin aka MuthaF'er]

I thought it might well be a pinch fit like you mention. Well then I must have excessive play in there if it is moving. Need to figure that out. The 550's cross reference to the late K's and early F's so that would make sense. And the wheel was rolling soooo well. Guess I need to start with snugging down my axle, huh    Thanks for the insight. 4 manuals on hand too  they say "and tighten the front axle nut". Period.

[754]

Yes tighten axle, has to be inserted from correct side.
The speedo drive plate, must anchor to the hub....that is what the chrome cover does.

[Jerry Rxman Griffin aka MuthaF'er]

Removing the caliper and preventing the pad drag first has allowed me to continue tightening the axle nut until it begins to drag then back off slightly to get free rotation. Prior to this I did not feel any free play? Guess this is what stumped me. The gear box is staying put. Now I need to disassemble the caliper and insure I have smooth pad travel without drag there. Back to it. 

[754]

Dont back off axle nut.

[kmb69]

Dont back off axle nut.

+1. The axle nut should be tight. Front axle nut torque per the manual is 5.5 - 6.5 kg-m or 39.8 - 47 lbs-ft.

You have another issue if you are having to back off the axle nut from those values for the wheel to spin freely.

.....
Thanks for the insight. 4 manuals on hand too  they say "and tighten the front axle nut". Period.

Check the torque value table in the back of the manual. 

[754]

Sounds a bit like when center spacer is missing.
 Give it the single digit finger exam......

[Jerry Rxman Griffin aka MuthaF'er]

OK thanks for the advice. I'll check the nut tightness. I didn't find that figure in the book. I'll look again.

Brake back together with lube on the outer disc surface. It's self bleeding as we speak. Back to it tomorrow.

[my name is nobody]

I have an older (K0) front hub and speedo gearbox with everything. Got some pics of stuff if it'll help ya

[Jerry Rxman Griffin aka MuthaF'er]

Thanks Nobody. I may have it figured out. I'll shoot you a PM if it might help out.

[scottly]

Here are a couple of pics of the bearing/spacer stack.
The two notches in the drive plate have to be aligned with the nubs inside the gear box, if not, the assembly will lock up when the nut is tightened, and if over-tightened may damage the plate or box. With the nut fully tightened, the axle should spin freely in the wheel.(I always do this part with the wheel removed from the bike.) If it does, mount the wheel in the forks, and position the gear box where you want it and tighten the fork clamps.
The Honda front hub isn't symetrical; if reversed left to right, it will shift the center of the tire and the brake rotor to one side, with may cause the brake to be out of alignment enough to bind. While the drive won't work with the stock Honda wheel reversed, it will with a Morris wheel, and possibly a Lester too.

[DickL]

I'd like to see the pictures of the 1970 parts. I cracked the speedo housing. The retainer was installed wrong with the wings.