RGM pre-Commando belt clutch experiment for P11

APRRSV said:
Does anyone know whether Roger is now RGM's only employee? I've placed a couple of orders with him lately with slow turnaround and no answer to email questions concerning other parts I may need.


Ed
Click to expand...
Presently having the same trouble...
 
Back to the clutch

Under power to the road the belt moves the other way toward the outside of the pulleys. I wouldn't have been able to align the belt running the motor with the outer primary off since it moved in the other direction on the pulleys when using that method. Still not done with it. More moving the gearbox around and more testing required to get the belt aligned.

I'm guessing it is "not" normal for the noises and feel coming out of the primary to give the impression the belt is about to pile up in front of the engine pulley on deceleration in 2nd gear. I went a few blocks on the last test run and wasn't sure I was going to make it home without pushing it uphill. Real happy I made it back.

Primary had a little bit of light green fuzz off the belt in it and some black rubber fuzz from a rubber plug in the outer cover near the top center of the belt run. I'm thinking the only thing keeping that belt on the rear pulley was the outer case. Sure sounded like hell slapping on the case on deceleration. I felt like I was riding a washtub bass. :)
 
I think Roger is really struggling to keep up to a great business. He isn't a young guy. Last time we talked he said he had gotten behind with answering emails and had nearly a thousand to answer.
He said " I don't know what I'm going to do" He seemed quite worried about things. We are all aging but perhaps the reduced energy levels aren't such a big deal for those of us who are retired.
If I do half of nothing in day rather than a full nothing, who is going to notice?

I've bought a lot of stuff from Roger and it's always been good quality. He has designed and produced a lot of very special lightweight parts for Nortons. The prices are reasonable too.
For selfish reasons, I hope he can carry on for awhile yet.


Glen
 
Not complaining about the RGM clutch, but I gotta say it is not that easy to get the belt where it doesn't go to one rail or the other on the engine pulley. So far I have verified I can make it go from one rail to the other. What I have not been able to accomplish is getting it to ride just off the inside fence (if you will) of the engine pulley. Fine line and it has to be done at both the top and bottom gearbox mounts. Can't be accomplished trying to cock the gearbox to ones will using only the top mount adjustment. At least not on the P11 with me doing it.

The experiment continues.
 
Note about Bolton Engineering Products:

The belt I ordered from Bolton showed up today, and it is the cheaper older standard Grey colored Continental 20AT10 880 belt instead of the Red Continental 20AT10 880 Generation 3 belt that I ordered. The Red Generation 3 belt is 25% stronger and has a higher temperature specification. Am I happy about it and do I feel sorry for Bolton because they made a mistake, Heck No. 🤬
 
Schwany said:
Not complaining about the RGM clutch, but I gotta say it is not that easy to get the belt where it doesn't go to one rail or the other on the engine pulley. So far I have verified I can make it go from one rail to the other. What I have not been able to accomplish is getting it to ride just off the inside fence (if you will) of the engine pulley. Fine line and it has to be done at both the top and bottom gearbox mounts. Can't be accomplished trying to cock the gearbox to ones will using only the top mount adjustment. At least not on the P11 with me doing it.

The experiment continues.
Click to expand...
I wasn't able to get the belt to track just right on the 920. It always walked out at the front when under hard acceleration.
I ruined one belt and one stator then made up a big washer to hold the belt in place. The kit came with a flange on the inside of the front pulley but nothing on the outside. The big diameter washer is now the outside flange, so the belt is trapped on the front pulley.
I bought the kit off ebay, I think it is an early RGM kit. It was unused but had been sitting around for years.
So far all is OK with the way it is running with the double flange at the front pulley, no sign of belt wear. Haven't done huge mileage though.


Gleb
 
worntorn said:
I wasn't able to get the belt to track just right on the 920. It always walked out at the front when under hard acceleration.
I ruined one belt and one stator then made up a big washer to hold the belt in place. The kit came with a flange on the inside of the front pulley but nothing on the outside. The big diameter washer is now the outside flange, so the belt is trapped on the front pulley.
I bought the kit off ebay, I think it is an early RGM kit. It was unused but had been sitting around for years.
So far all is OK with the way it is running with the double flange at the front pulley, no sign of belt wear. Haven't done huge mileage though.


Gleb
Click to expand...
thanks Glen

The newer RGM kit for the pre-commando has a big round flange plate that is up against the outside of the engine pulley. It is pushed up against the pulley with the alternator rotor when the pulley is torqued down. In my case the belt would come off the clutch pulley if it weren't for the outer case half. The clutch gets real noisy when the belt is anywhere near the outside edge of the clutch pulley.

Anywho, it appears that the Continental belt I just got from Bolton tracks better than the belt I got from PolyTech. The Continental belt has slightly deeper teeth is thicker in general and not as slick. I think I have a handle on getting the belt to go in the direction I want it to go. The one good thing is that when the belt moves toward the engine it never comes close to coming off the clutch pulley, so I may end up running it very close to or touching the inside flange on the engine pulley. Sort of a whatever works approach.

Last time I had the motor running the PolyTech belt looked like it was working then suddenly started heading to the outside edge of the clutch pulley after hard acceleration and deceleration. Probably similar to what you experienced. In my case I believe something changed position when I wacked the throttle open and let it off. I'll be looking into all that today and maybe get it done before too much longer. Might get done with it before summer is over.
 
Kind of threw in the towel on trying to adjust the gearbox to get the belt where I wanted it. The belt refused to go in toward the engine again. The gearbox likes to stay inline with the front pulley, and not be cocked to one side or the other either. Imagine that? The belt stayed to the engine side when everything was only torqued to 50lbs, then it stopped doing that when I torqued the engine pulley and clutch down fully.

Fix is to reduce the width of the engine pulley by a little over 8mm. The overall width would be under 22mm. This is similar to what CNW does using a narrower engine pulley with the 21mm belt set up. Difference in my case is I won't have an outer flange on the clutch pulley like CNW has.

RGM sent me the wrong 30mm wide engine pulley and wrong belt. The hub is correct, but I would not be that surprised if the clutch basket was also wrong for this kit (too wide and missing an outside flange). I could order the correct 20mm pulley for pre-Commandos from RGM, but I don't know what I would get given how things are, so I'll get the pulley machined. I don't know what the hell poor Roger was thinking when he sent me the wrong parts. It's cost me too much time trying to make the wrong engine pulley work to get my poor Roger sympathy meter to move much off zero.
 
When your narrowing the 30 mm engine pulley cut a small shoulder on outside and bolt on a flange. Four button heads would look great, and do what is needed!
I know Monday morning quarterbacking, can't help myself.
 
  • Like
Reactions: baz
mean gene said:
When your narrowing the 30 mm engine pulley cut a small shoulder on outside and bolt on a flange. Four button heads would look great, and do what is needed!
I know Monday morning quarterbacking, can't help myself.
Click to expand...
Already has a flange that slides up on the crank shaft and gets pressed up against the pulley center and edge of teeth by the rotor. Roger designed it right. He (or whatever inexperienced help) sent me the wrong parts for the kit he is selling. And the damage in shipping. You can see one of the smaller nics in the teeth below.

I'll have to use my stock rotor spacer after the part is cut.

Your idea is good. Unfortunately, there isn't a lot of meat for a shoulder. Just a big assed cut across the entire end is what I want.

RGM pre-Commando belt clutch experiment for P11


RGM pre-Commando belt clutch experiment for P11
 
I understand your belt frustration now. I see that's it's a different style belt then Newby uses.
 
RGM in the title of the post is a dead giveaway it's not a Newby clutch. :)

Newby and just about everyone else uses an 8-pitch belt and pulleys. RGM uses a 10 pitch.

The RGM pre-Commando clutch would have worked out of the gate once I got the right length belt if RGM would have sent a 20mm width engine pulley instead of a 30mm engine pulley. I do like the diaphragm spring after using it, and didn't want to work with the wider belt Newby uses. 6 spring clutches like the Newby can be a little stiff without hydraulic assist. I tried a NEB 6 spring wet cutch, and they are similar to a Newby clutch. Stiff with a suitable Venhill cable. NEB sells a 6 spring belt clutch as well.

It would not have been much more fun fitting a Newby clutch on a P11. I would have had to use a wider full perimeter spacer on the primary case, and perform other modifications to make a Newby clutch work.

Mechanical work is a piece of cake with the right parts. This post probably would have ended shortly after the first page if I had received the right parts. Using the wrong parts can be frustrating though. And I do like to complain about vendors when warranted. Letting stuff slide is not something I do well.
 
Schwany said:
Newby and just about everyone else uses an 8-pitch belt and pulleys. RGM uses a 10 pitch.
Click to expand...
The late Tony Hayward used the AT10 design as well. I don't think there is anything wrong with the basic design.
Schwany said:
The RGM pre-Commando clutch would have worked out of the gate once I got the right length belt if RGM would have sent a 20mm width engine pulley instead of a 30mm engine pulley.
Click to expand...
Perhaps, although I think Roger's design using a floppy keeper plate for the engine pulley is a cock-up. Strangely, he offers other pulleys for singles etc. with keeper plates made of steel and fixed by 4 crews on the pulley itself, mirroring the inner keeper plate. Such an arrangement provides much stiffer keeper plates, approaching the stiffness of flanges, so why didn't he make all pulleys like that? A small flange for centralising would make the keeper plate design good.

A rubber belt does not behave on its own - it needs a short run as well as firm guidance, which the engine pulley is supposed to provide, by correct width and stout large flanges. You are moving in the right direction by reducing width of the pulley. I suggest you alter the outer keeper plate design as well, and consider enlarging OD of both keeper plates. Alternatively, have a one-off pulley made with integral flanges, that's what I am looking at.

- Knut
 
Last edited:
One off pulleys are EXPENSIVE! I asked Newby to make me a 3 in wide engine pulley, for a duel engine project,and the price was $750!
 
mdt-son said:
The late Tony Hayward used the AT10 design as well. I don't think there is anything wrong with the basic design.

Perhaps, although I think Roger's design using a floppy keeper plate for the engine pulley is a cock-up. Strangely, he offers other pulleys for singles etc. with keeper plates made of steel and fixed by 4 crews on the pulley itself, mirroring the inner keeper plate. Such an arrangement provides much stiffer keeper plates, approaching the stiffness of flanges, so why didn't he make all pulleys like that? A small flange for centralising would make the keeper plate design good.

A rubber belt does not behave on its own - it needs a short run as well as firm guidance, which the engine pulley is supposed to provide, by correct width and stout large flanges. You are moving in the right direction by reducing width of the pulley. I suggest you alter the outer keeper plate design as well, and consider enlarging OD of both keeper plates. Alternatively, have a one-off pulley made with integral flanges, that's what I am looking at.

- Knut
Click to expand...

If you have the equipment to do it go for it.

The outer keeper plate is steel. It's not floppy at all with the rotor up against it torqued to 90ftlbs. It will have the potential to be a little floppy when I get done reducing the width of the pulley though. I have to use either the stock spacer, which would let it be floppy if it ever could be floppy, which I doubt, or a larger diameter shade tree engineered spacer to space out the rotor. Ideally a rotor spacer the same diameter as the rotor would be best against the keeper. The fit of the keeper plate is very tight on the crank shaft. I won't be screwing the keeper plate to the pulley. I won't be making a one-off pulley either.

The keeper plate is tall enough to keep the belt from climbing over it. I won't be running the belt so loose that it could jump up and climb over the keeper plate.

Little side note for those that don't have a complete machine shop at their home. The cost of a one off pulley made by a prototyping machine shop would be redamndickulous. (Note Gene's response, and some logic would tell most people that was the case.) Unfortunately, the machinists I have talked with to date don't want anything to do with reducing the width of the pulley. Besides merely cutting it down would put it in machinist's jail for a month. Heck with that.

RGM wants $78US plus $36 shipping for the pulley that supports a 20mm belt. I think it might be a little wider than I want. It's probably 23mm. I'm going with 21mm.

Anywho, getting out the surrogate lathe/bridgeport AKA hacksaw and a sharp blade. Might take all day to make the cut a flat surface. Yippee
 
Schwany said:
If you have the equipment to do it go for it.

The outer keeper plate is steel. It's not floppy at all with the rotor up against it torqued to 90ftlbs. It will have the potential to be a little floppy when I get done reducing the width of the pulley though. I have to use either the stock spacer, which would let it be floppy if it ever could be floppy, which I doubt, or a larger diameter shade tree engineered spacer to space out the rotor. Ideally a rotor spacer the same diameter as the rotor would be best against the keeper. The fit of the keeper plate is very tight on the crank shaft. I won't be screwing the keeper plate to the pulley. I won't be making a one-off pulley either.

The keeper plate is tall enough to keep the belt from climbing over it. I won't be running the belt so loose that it could jump up and climb over the keeper plate.

Little side note for those that don't have a complete machine shop at their home. The cost of a one off pulley made by a prototyping machine shop would be redamndickulous. (Note Gene's response, and some logic would tell most people that was the case.) Unfortunately, the machinists I have talked with to date don't want anything to do with reducing the width of the pulley. Besides merely cutting it down would put it in machinist's jail for a month. Heck with that.

RGM wants $78US plus $36 shipping for the pulley that supports a 20mm belt. I think it might be a little wider than I want. It's probably 23mm. I'm going with 21mm.

Anywho, getting out the surrogate lathe/bridgeport AKA hacksaw and a sharp blade. Might take all day to make the cut a flat surface. Yippee
Click to expand...
There must be plenty of folks on here with a lathe who who would be able to do it for you.
 
cliffa said:
There must be plenty of folks on here with a lathe who who would be able to do it for you.
Click to expand...

If what I do today doesn't work, I'll order the part from RGM. I think it will work well enough for an old Norton. I have saw skills and too much confidence for my own good. lol

Almost halfway through.

RGM pre-Commando belt clutch experiment for P11
 
Schwany said:
Unfortunately, the machinists I have talked with to date don't want anything to do with reducing the width of the pulley. Besides merely cutting it down would put it in machinist's jail for a month. Heck with that.
Click to expand...
That's weird. It's an easy part to put in a lathe chuck or on a milling machine table and face off what you need. I would understand that a machinist doesn't want to take responsibility for it working, but it makes no sense why they wouldn't do what you want, within the tolerances you call out.

As far as I can tell, Newby's pulleys have a small shoulder, with a press-fit aluminum ring as the flange/keeper on the outside. If assembled and aligned correctly, there is very little side load on the guide from the belt. It seems as though you've done plenty to insure that it's running and aligned correctly and your guide plate is more than adequate, in my opinion. In almost any belt drive solution, the belt is sacrificial. It's rubber for Pete's sake...

Your plan seems like a good one to me, but I've got a lathe and mill. A hacksaw and an afternoon makes my eyes roll back in anticipated boredom, and my fingernails curl over anticipated tolerances. I'd be happy to face it off, but it's hard to imagine someone closer wouldn't do it for you.

EDIT: Ha! Too late! "Safety with Style" indeed...
 
Schwany said:
If what I do today doesn't work, I'll order the part from RGM. I think it will work well enough for an old Norton. I have saw skills and too much confidence for my own good. lol

Almost halfway through.

RGM pre-Commando belt clutch experiment for P11
Click to expand...
Well at least you have a quality hacksaw;)
 
I don't understand why RGM doesn't send you the correct part at their cost.


Glen
 
You must log in or register to reply here.
Back
Top