Speedometer gear unit on front wheel of a 66' Scrambler

[moondoggers]

When I bought the 66' Scrambler the P.O. was in the middle of a restore when he had to sell the scrambler due to illness so among other parts the speedometer cable was missing. My focus was to get the motor running,using the Ed Moore tune-up procedure found on this forum and Bill Silver's tune-up procedure taken from his restore guide I was able to get the motor firing on both cylinders. Now I am gathering missing parts to make this bike street legal and I bought a new speedometer cable on E-Bay.
I installed the new cable took the bike for a run and found the speedometer needle stayed on zero so after getting some advice on how to determine if the speedometer in the bucket was stuck I ruined a new cable, a used replacement is on it's way from E-Bay.
Now to the original question: On a 66' 305 scrambler what is the purpose of the philips head screw on the speedometer gear drive on the front wheel?
Is it a set screw or for lubrication and does the unit float on the font axle? Obviously the gear has to be in a neutral position so the cable won't bind.

[conbs]

Your speedo drive should not "float". If it does, it will move until it binds, make noise and eventually wear out your speedo cable - perhaps the problem you have had. Some guys have had a problem with that. It should be clamped in place by the axle.

When you put your front axle in, just snug the pinch bolts where the axle goes through the forks. Tighten your axle and that will clamp the speedo drive in place. Then tighten the pinch bolts.

If you tighten the pinch bolt first, the axle nut can't clamp the speedo drive. Also, make sure your the tangs on the back side of the speedo drive are down in the slots in the wheel. If not, it will rub and make noise (probably eventually wearing through and causing some kind of issue).

I hope that helps

[moondoggers]

Thanks a bunch, that's exactly what I needed to know.
One more question, what size mm open end wrench fits that nut? A 17 or 18 and I'll have to grind it down to fit between the fork leg and the speedo hub.
Very cool information.
Martin

[conbs]

I am not sure I understand your question. Can you post a pic?

[moondoggers]

I'm talking about the axle nut between the right fork leg and the speedo drive. There is not enough room for a standard width open end wrench. There must be a thin open end wrench to tighten that nut.
I have to guess it's an 18 mm open end wrench that I will have to grind down to fit.

[conbs]

It would still be helpful to have a pic of what you are dealing with but, I may have figured it out.

I just looked at my shop manual and it says tighten the axle nut last. Hmmmm. I think that leads to the "float" problem with the speedo drive. The part of the speedo drive that drives the cable should be on the bottom withthat flat side about parallel to the ground so the speedo cable makes a nice smooth arc. It needs to stay in that position and the only way I can see to do that is to tighten the axle nut before the clamp bolts are tightened. Shop manual says 91 ft lbs on the axle nut so it is supposed to be really tight.

I had always thought the "nut" part of the late axle nut goes to the outside so you can reach it and avoid the problem you seem to be having. But I see the parts manual shows it with the "nut" part to the inside. Hmmm.

You should be able to take the clamps off and remove the front wheel. Turn the axle nut around. Put the wheel back on with the clamps just snugged. Tighten the axle nut, which you should now be able to reach, and then tighten the clamps. I also think it is a good idea to make sure that neither side of the forks is being stressed laterally. I would loosen the clamps and let everything come to rest before finally tightening the clamps.

That is how I would do it. If someone disagrees I hope they will weigh in and straighten both of us out.

[LOUD MOUSE]

Tighten the large nut thing to the axle.
Install wheel then install clamps. .................................lm

It would still be helpful to have a pic of what you are dealing with but, I may have figured it out.

I just looked at my shop manual and it says tighten the axle nut last. Hmmmm. I think that leads to the "float" problem with the speedo drive. The part of the speedo drive that drives the cable should be on the bottom withthat flat side about parallel to the ground so the speedo cable makes a nice smooth arc. It needs to stay in that position and the only way I can see to do that is to tighten the axle nut before the clamp bolts are tightened. Shop manual says 91 ft lbs on the axle nut so it is supposed to be really tight.

I had always thought the "nut" part of the late axle nut goes to the outside so you can reach it and avoid the problem you seem to be having. But I see the parts manual shows it with the "nut" part to the inside. Hmmm.

You should be able to take the clamps off and remove the front wheel. Turn the axle nut around. Put the wheel back on with the clamps just snugged. Tighten the axle nut, which you should now be able to reach, and then tighten the clamps. I also think it is a good idea to make sure that neither side of the forks is being stressed laterally. I would loosen the clamps and let everything come to rest before finally tightening the clamps.

That is how I would do it. If someone disagrees I hope they will weigh in and straighten both of us out.