650SS Rearsets

t ingermanson said:

Hmmm. I was wondering if an obtuse angle at the linkage rod and gearbox shift shaft lever may not exert only rotational force, splitting it with force just side-loading the shaft. Maybe so. Did you try the shorter lever at a noon position?

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I tried it at several angles including noon - I cannot explain it - it really seems like shorter would be better. The gearbox is very smooth with a normal lever.

Those look like RGM rearsets with stock foot peg rubbers.

robs ss said:

I made a set for my featherbed 500 - essentially the same frame as yours. I used a set of universal rear sets as the basis - only had to make the "lever plates" for brake & gearshift. Best part is that you control the lever length & hence the ratio, You also determine where you put the toe-piece.
The Tarozzi is an excellent design, in that the entire footage length is the bush so you will never get any slop.

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Find great deals on eBay for Tarozzi Rearsets. Shop with confidence.

www.ebay.com.au

I used "fixed" pegs on both sides and the RGM kickstart lever clears them without the need for a folding peg.
Cheers
Rob
View attachment 18045

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Rob, whilst I know this is completely off subject, I have to say I love everything in that picture. It is really a work of art which you should be proud of. Did you post pictures in the build forum? if so can you post the link, If not can you post some more piccies?

Cheers,

cliffa.

I'm back on this bike now. The shifting is good enough. The bike was converted to belt drive but the primary cover drain plug was not installed and oil dripping from there when the bike was leaned over. Took the cover off today and there was about a pint of stinky motor oil still in it so I figure I need to change the crankshaft seal. Also, the rotor nut has been rubbing on the inside of the primary outer cover which is chromed steel. I know Commandos, this is the first 650SS I've worked on. Any tips/gotcha's I should know about?

Hi, about the rotor nut grubbing , did you shorten the spacers of the stator so the rotor is flush with the crank pulley ?? if not , do it that will put the rotor more inside and thus the nut ........otherwise , I know that when I had bought the kit for my Atlas they supplied a spacer to go between the outer cover hole/footrest hanger big "bolt " to make this cover a bit further out ........

marinatlas said:

Hi, about the rotor nut grubbing , did you shorten the spacers of the stator so the rotor is flush with the crank pulley ?? if not , do it that will put the rotor more inside and thus the nut ........otherwise , I know that when I had bought the kit for my Atlas they supplied a spacer to go between the outer cover hole/footrest hanger big "bolt " to make this cover a bit further out ........

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The rotor is flush with the stator. There was no spacer and in fact something must be missing as there is nothing to stop the cover from going inward other than the flange in the cover. The center is simply a hole and there's no kind of stop on the foot peg holder - probably due to the rear sets. Thanks, now I know one thing to study!

robs ss said:

I made a set for my featherbed 500 - essentially the same frame as yours. I used a set of universal rear sets as the basis - only had to make the "lever plates" for brake & gearshift. Best part is that you control the lever length & hence the ratio, You also determine where you put the toe-piece.
The Tarozzi is an excellent design, in that the entire footpeg length is the bush so you will never get any slop.

Tarozzi Rearsets for sale | eBay

Find great deals on eBay for Tarozzi Rearsets. Shop with confidence.

www.ebay.com.au

I used "fixed" pegs on both sides and the RGM kickstart lever clears them without the need for a folding peg.
Cheers
Rob
View attachment 18045

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Nicely done.

Next problems. The rotor was a real bear to get off - zero room behind it and stuck on the shaft. I did get it off without damaging anything. Next problem. That brass disc behind the rotor has been lightly rubbing on the back of the stator. There are no spacers anywhere and the rotor lines up flush with the stator. I'm assuming that the front "sprocket" is out too far causing the brass disc to rub and the rotor nut to rub the inside of the outer primary cover.

The crankshaft taper looks good as does the taper inside the "sprocket" and they were VERY tightly together. I'm thinking I may have to lap them together to get the "sprocket" a little farther on the crank.

When I got it all apart, the crankshaft seal is in place. There is evidence of slight weeping there and from two of the screws. I expected to see it out of place. It is a weird seal. It looks exactly like the Commando seal in that it appears to be brass colored metal with rubber inside. However, the part that normally metal is brass colored but rubber. I filled the crankcase to the middle of the crank and will check later if oil has leaked. Right now I'm guessing that it only leaks when running

Questions:

Can anyone identify the belt drive kit?
Does lapping the crankshaft/"sprocket" sound right?
What is the correct name for the front "sprocket" with a belt drive?
Has anyone else seen an all rubber crankshaft seal?

The belt drive kit looks like it could be an RGM one - they use an AT10 Synchroflex belt which is what it looks like you have there (although RGM have now moved to the red gen III belts)
They also use the Commando clutch.
We have one on a 650ss and it’s superb.

Just fitted a Bob Newby kit to a different 650ss project and we ended up machining out the taper a little on the drive pulley to get it further on the crankshaft.
It was hard anodised and certainly wouldn’t have lapped on with grinding paste.

I don’t like the rubber seals - we tried one and it leaked.
I like the metal ones which have a rubber covering - and I fit them with a smear of JB Weld, I think Jim Comstock recommended that trick.

Regards the crankshaft nut - we had the same issue with it rubbing in the cover.
We machined it down on the length, it’s fine now.

gtiller said:

The belt drive kit looks like it could be an RGM one - they use an AT10 Synchroflex belt which is what it looks like you have there (although RGM have now moved to the red gen III belts)
They also use the Commando clutch.
We have one on a 650ss and it’s superb.

Just fitted a Bob Newby kit to a different 650ss project and we ended up machining out the taper a little on the drive pulley to get it further on the crankshaft.
It was hard anodised and certainly wouldn’t have lapped on with grinding paste.

I don’t like the rubber seals - we tried one and it leaked.
I like the metal ones which have a rubber covering - and I fit them with a smear of JB Weld, I think Jim Comstock recommended that trick.

Regards the crankshaft nut - we had the same issue with it rubbing in the cover.
We machined it down on the length, it’s fine now.

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The belt is a Gates HTD 976-8M. The pulley and clutch basket are anodized. The leak is coming from the seal - it leaked about two drops over night. The bike was last registered in AU in 2002. I don't know when it came to the states or when it was converted to rearsets and/or belt drive, but I assume long ago. However, the belt and other components look new. But the oil in the primary was definitely motor oil, black, and stunk. The current owner never had the primary cover off.

It turns out that the trouble with getting the rotor off was burrs on the shaft - an easy fix.

The taper on the crank also was not smooth so I spent time with a very fine file and 220 grit - before I started, the pully would slightly rock when pushed on the taper by hand in different locations and would not turn on the taper when lightly held on. That's corrected but I have no idea if that's a enough to move it in.

The footrest tube (part in the AN picture) is not centered in the inner cover and moves back and forth about 1/8" - are both of those OK?

Les Emery at Norvil uses HTD belts and does a kit for the Dommie, so that could be a likely candidate.

gtiller said:

Les Emery at Norvil uses HTD belts and does a kit for the Dommie, so that could be a likely candidate.

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Thank you! The kit is clearly Norvil. I wrote and asked for the fitting instructions and they sent them. It turns out that there is a missing spacer that goes over the footrest mount. Also, it seems like the stator needs a slight outward spacing to stop the brass disc from rubbing. There were extra washers on the outside of the stator that were doing nothing - they probably should have gone between the stator cradle and spacers. I'll see when I re-assemble.

The saga continues...

Replaced the crank seal - that went smoothly. Put everything together per the fitting instructions and tested the belt alignment, again per the instructions. The belt tracks to the front. Put it in the middle of the pulleys and within 20 turns of the engine is is hanging off the engine pully. It has been this was as the front edge of the pully has been rubbing on the retainer. Of course it stays on with the retainer, but I'm sure in more that a short ride it get very hot. on reflection, that's probably why the oil stunk.

I spent a lot of time trying to twist the gearbox where it will track correctly but never got anywhere. I'm HOPING that the frame or engine/gearbox cradle are not bent!

This kind of thing is why I only build stock bikes and while I'll not take in another even to help a guy out

We added a second adjustment lollipop to our 650ss when we fitted the RGM kit.

Originality on this bike wasn’t important, as there are already a number of non-standard tweaks.
It‘s also important not to have the belt too tight - you should easily be able to twist it through 90 degrees.

gtiller said:

We added a second adjustment lollipop to our 650ss when we fitted the RGM kit.

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I may have to do this but I haven't figured out yet how to get access. So far I haven't even figured out how to change the bottom gearbox stud (threads aren't great). Basically, it looks like a lot of the bike has to come apart to do either. I need to find a workshop manual.

It’s a bit generic, but it’s better than nothing http://classicbike.biz/Norton/Repair/1960s/NortonRepair1960-1968.pdf

We always replace the bottom stud for two bolts and a tapped bar - make life easier in the future.
Andy Molnar does a kit if you don’t want to make one yourself.

FG51
Special 3 part replacement for FG50, makes it possible to remove gearbox without taking out the engine!
Can only initially be installed when gearbox is out of frame.

I can highly recommend doing this!

You can remove the front engine plate to frame studs, the centre stand through bolts (if they are there) and the bottom rear engine plate to frame bolts then pivot engine and gear box up on the remaining top rear bolts.
We do it with a small jack and wooden block.
That allows you to push the bottom gearbox stud out.

I finally got the belt running true - counterintuitive! If I ever install decide to install a belt drive I will only do it with the bike apart and I will absolutely install an adjuster on the timing side. This was a nightmare.

Norvil is sending me the damaged/missing parts FOC - thank you Norvil!

There is a missing spacer causing the outer cover to move inward too far and there were incorrectly installed thin spacers to move the stator out from the retainer and the belt has been damaged by running incorrectly. Also, the footrest stud is bent causing the mount to not center in the outer cover correctly. Apparently, whoever installed the belt drive didn't bother to read the instructions.