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650ss, Slimline Frame, Rear Wheel Centreing, Spacers, Brake Drum / Sprocket, Brake Plate

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Hi all

Am returning to a job I tried to "bottom" years ago, to try to sort the rear wheel on the 650SS, year 1966.

The spurious spacers, which sent the wheel to the right (looking from the back) are removed and,dealer supplied, spacers fitted. This has pushed the wheel to the left. 

The new brake shoes were oversize and took a LOT of reducing (see forum topic 2017 from other annoyed owners!).

Having got the wheel turning, because it favours the left side the Torque Pivot Pin is more snuggly into the groove in the swinging-arm. The wheel will no longer align (tyre dragging on swinging-arm at right side).

I know I went through the wheel centreing years ago but am going to measure the wheel and make sure there is no off-set built in, and check sprocket / chain alignment again.

That brings us to the Brake Drum / Sprocket (unknown source, on bike when purchased. Sprocket teeth good but drum tapers to become larger to the outside. [Very large washer / spacer used inside it, not the 067603 shim(s)] with new sleeve nuts and another set of brake shoes, to start again. Possibly £210.00

If you can fault any of the above, please let me know.

I checked the Torque Pivot Pin, fig 30, 19847 / 019847 has stayed the same through the 650SS production. So have the spacers, Left, fig 29, 19268 / 067740 and Right, fig 19, 18235

The only other item I'm unsure of is fig 23, Rear Brake Plate which I understand was 19852 / NM19852 and something was changed in 1966 when the part number became 25453 / 060332.

Has anyone any idea what was changed because that would add £200 to £250 to make it right. Would it affect the wheel spacing?

That was the objective when I started this (frustrating) exercise.

Any help appreciated.

Of course, I could just fit the Mickey Mouse parts back and take up .........

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Hi Tim, I am working on my 63 SS and have found some issues with the rear brake too. Shoes too thick , shoes too wide for drum, shoes contacting back of drum Brake plate distorted possibly by action of later raised lever action. Pattern drums from India can be out of tollerance . I dont know if other parts were affected by the switch to wider sprockets and chains. The tyre should sit centrally in the forks and between the suspension units.

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A common mistake when re-assembling a Dominator wheel, from individual parts, is getting the bearing spacer the correct way round. The spacer shoulders have slightly different lengths, which look as though any fitting will be fine. It is not.  See the extract & photo below..........

Wheel BitsBearing Spacer

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Hi Robert and Phil

Thanks for your help

I've even got that section underlined in my manual.

Yes it seems to be pointing towards renewing the Brake Drum / Sprocket, from the N' dealer.

If you have time, could you check the length of spacers fitted to your F/bed Slimlines please, mine are;

Fig 29, Left spacer 067740: 0.60" (15.3mm)

Fig 19, Right spacer 18235: 1.075" (27.3mm)

 

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My first Atlas rear drum / sprocket lasted around 95,000 miles. I replaced it with a an Egremont Made in England pattern part. This got pointy teeth in only 5,000 miles. Renolds chains, back in the 60/70s were  also quality items that had a good service life. Those sold under the same brand name these days are just rip-off rubbish.

This is such a primary chain after just 150 miles from new. A tapping noise started coming from my rebuilt 99 which I attributed to an engine issue.  It was actually the primary chain waving around and bouncing off the chincase walls.

primary

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Hi All

Decision made, new parts ordered. I'll report back, even if I've made the wrong decision.

Parts (poor) quality is something I'm v interested in. Sometimes we can throw good money after bad "trying to make a silk purse out of a sows ear"

Had the same experience as you Phil with Primary Chain; rubbish out of it's box! From N'dealer. Replaced with Jvis from The Chain Man. Fantastic quality.

Hi Howard, am concerned the brake drum / sprocket is the root cause of above problems so,reluctantly,replacing

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Hi all

New parts arrived (Brake Drum/Sprocket, and Brake Shoes)

Drum fits more snugly to the Hub.

Brake shoes have "Slippers" or "Thrust Pads" at the cam end

and all the info' I can find says leave them fitted.

Brake shoes dragging on the drum. (out of the package). Not as bad as the last lot but not acceptable.

So, unless anyone can suggest anything else...

come Monday I'll go from 2 to 3 shims (between drum and brake plate) and start filing the linings to suit

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Hi Tim,  Several pattern brake shoes I have found to have slightly oversize  alloy ends that when fitted held the cam out of the plate a fraction , then once the lever nut is tightened tips things a tad out of true and makes the action a bit stiff . a rub with a file sorted it.

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Thanks Robert

I'll check that.

Distance between the Swinging Arm Forks = 7 7/8" (200 mm)

Top hat spacer on speedo' g/box checked against another new one.

Wheel built central to hub and now mounted centrally between Sw' arm with the new spacers.

It all goes together far better than before, just need to reduce the linings to stop the rubbing

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As promised (belatedly!), my findings:
1) Everything (chain, sprockets, brake) work far better when correctly aligned as the factory intended. If in doubt replace with N' factory supplied parts.

2) Smoother transmission, than before, reduced vibration and noise from that area.

3) Superior rear brake with torque arm cam support (Commando mod'). Gives far more confidence in today's manic traffic. Rear brake lost the "vague" feeling.

Was it "worth" it? It very much depends on personal opinion. I cancelled a magazine subscription
when they kept on about "bodging" in the workshop! I want my machinery to be as good as factory standards or improved by proven modifications. "You pays yer money and takes yer choice".

 



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