help

bryan b · Mar 24, 2014

Hi all
i am new to the forum i have a 71 commando that i have just bought and i have taken the rotor off to replace the drive belt as it does not seem to be in line as it has worn the outermost edge of the belt off and filled the case with rubber , two questions one should there be any play in the rotor i.e. between the keyed centre boss and the outer body and how do you ensure the pulleys are aligned. Any help would be most appreciated.

Bryan

toppy · Mar 24, 2014

The alternator rotor should be a close fit but should slide on or push on with little or no force. If the key is worn replace it (they cost pennies) but once the rotor nut is tight it should hold it in place. But if the bore of the rotor is to loose the this could allow it to move an affect the all important air gap.

Try using a straight edge off clutch drum to line pulleys up an it may be that clutch spacers on gearbox main shaft need changing if it was not set up right to start with.
If you dont have the twin lollypop type gearbox adjuster it may be worth thinking about one as thy can help in lining up.
You can run with primary cover off to see if belt runs ok but BE CAREFUL.

Matt Spencer · Mar 24, 2014

Oh Dear .

Later ones Stamped ' W ' for Welded - magnets to inner thing , dont come loose .

These Suckers do replacements for $ 100 .

LOOK here : technical-information-how-post-photos-t2357.html and if youd started there youd be here http://www.classicbike.biz/

thisd be a bit of use .

bryan b · Mar 24, 2014

toppy said:
The alternator rotor should be a close fit but should slide on or push on with little or no force. If the key is worn replace it (they cost pennies) but once the rotor nut is tight it should hold it in place. But if the bore of the rotor is to loose the this could allow it to move an affect the all important air gap.

Try using a straight edge off clutch drum to line pulleys up an it may be that clutch spacers on gearbox main shaft need changing if it was not set up right to start with.
If you dont have the twin lollypop type gearbox adjuster it may be worth thinking about one as thy can help in lining up.
You can run with primary cover off to see if belt runs ok but BE CAREFUL.

thank you for the reply my bike only has the one adjuster i did not look to see if there was provision for a second adjuster ! or do you have to drill back plate yourself ? .
regards Bryan

Beach · Mar 24, 2014

If the center keyed part is loose from the outer rotor part replace right away...They have a habit of doing this and can cause a really big mess..Like Matt said they make welded ones now to correct the problem..

bryan b · Mar 24, 2014

Matt Spencer said:
Oh Dear .

Later ones Stamped ' W ' for Welded - magnets to inner thing , dont come loose .

These Suckers do replacements for $ 100 .

LOOK here : technical-information-how-post-photos-t2357.html and if youd started there youd be here http://www.classicbike.biz/

thisd be a bit of use .

Hi thanks for the help looks like i need to buy a new rotor as the one i have is not a welded type and as i said is loose

regards Bryan

toppy · Mar 24, 2014

.[/quote]
thank you for the reply my bike only has the one adjuster i did not look to see if there was provision for a second adjuster ! or do you have to drill back plate yourself ? .
regards Bryan[/quote]

Yes you need to drill a hole in the RH gearbox plate. I would drill the hole in front of the gearbox bolt not behind as it is on the LH plate as it will be better access with the inner primary cover in place.

bryan b · Mar 24, 2014

toppy said:
.

thank you for the reply my bike only has the one adjuster i did not look to see if there was provision for a second adjuster ! or do you have to drill back plate yourself ? .
regards Bryan[/quote]

Yes you need to drill a hole in the RH gearbox plate. I would drill the hole in front of the gearbox bolt not behind as it is on the LH plate as it will be better access with the inner primary cover in place.[/quote]

hi thanks for the tip i will do that

regards Bryan

Hobot · Mar 24, 2014

This placement worked well for me to install and access.

bryan b · Mar 25, 2014

hobot said:
This placement worked well for me to install and access.

hi thanks for the reply and pic most helpful,what is the maney part? Is this a street bike or a race bike .
kind regards Bryan

toppy · Mar 25, 2014

Its outrigger bearing that supports the sleeve gear and so helps to support the gearbox main shaft. In order to fit it you have to cut the hole in the inner primary case to make it larger but as you have belt drive then you dont have to worry about oil leaks etc.

rvich · Mar 25, 2014

Here are some photos of the double adjuster I put together. There are some commercially available.

edgefinder · Mar 25, 2014

I found a loose hub to rotor last night on a 73 850. Should I put a spare 71 750 rotor on or do all old rotors go bad sooner or later?

bryan b · Mar 25, 2014

toppy said:
Its outrigger bearing that supports the sleeve gear and so helps to support the gearbox main shaft. In order to fit it you have to cut the hole in the inner primary case to make it larger but as you have belt drive then you dont have to worry about oil leaks etc.

Thanks for that i thought it might be , is that a mod that is a good idea for a road bike or is it really a race mod !

regards Bryan

bryan b · Mar 25, 2014

rvich said:
Here are some photos of the double adjuster I put together. There are some commercially available.

Thank you for the pics very helpful.

regards Bryan

pete.v · Mar 25, 2014

bryan b said:
toppy said:

Its outrigger bearing that supports the sleeve gear and so helps to support the gearbox main shaft. In order to fit it you have to cut the hole in the inner primary case to make it larger but as you have belt drive then you dont have to worry about oil leaks etc.

Click to expand...

Thanks for that i thought it might be , is that a mod that is a good idea for a road bike or is it really a race mod !

regards Bryan

I think it is a good mod for any bike if running a belt.

My bike is a bit modified, cam, headwork, carb, etc. With the RBM belt drive the gearing is a bit on the high side even with a 20t sprocket. I decided to go to a 19t but I knew my main shaft was a bit worn and stressing it would be asking for trouble.

I re-bushed the gearbox and got a new main shaft. I felt if there was a time to add the outrigger it was now. So, I'm geared down with a new supported main shaft.
Not a race bike but should be considered Hot Street.

toppy · Mar 25, 2014

I am fitting one to my bike when I reassemble with its big valve tuned motor. Even though it will mean cutting the Alton Ekit inner primary case as I think its a worthwhile mod. I have the RGM belt drive with alloy clutch an a new mainshaft so hopefully with the outrigger added it should give not trouble as its a road bike.

bryan b · Mar 25, 2014

toppy said:
I am fitting one to my bike when I reassemble with its big valve tuned motor. Even though it will mean cutting the Alton Ekit inner primary case as I think its a worthwhile mod. I have the RGM belt drive with alloy clutch an a new mainshaft so hopefully with the outrigger added it should give not trouble as its a road bike.

Hi what are the details of the cut out in the inner case and is this the only machining needed , as this seems a worthwhile mod and as i have most of the parts off except the inner case seems like a good time to do it.

regards Bryan

Matt Spencer · Mar 25, 2014

The gearbox riddle is mentioned here : http://www.youtube.com/watch?v=a-SOXVVdIZ4

If you were touring hard out , blowing of riceburners at lights or the strip , or indulgeing in mono wheeling ,
the outrigger bearing should keep the teeth in mesh .

of course , there are ' further refinements ; if you want exclusiveity . :mrgreen:

Hobot · Mar 25, 2014

To fit Maney outrigger essentially means a big hole in case so mainly for dry belt primary only though I did seal Ms Peel's. If you are using full throttle at times even with a stock Commando it tends to jerk the life out of AMC guts. The outrigger mount thickness on LH must be compensated for to use the off the shelf SS dual adjuster top bolt and get enough threads for nut on RH. I thinned the mounts flats some.

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