Rear wheel spacers,

MS850 · Aug 30, 2015

Hello greetings from Roseville , Ca. Im new to forum, this is my 2nd post.
I have a question about my '75 MK3 rear wheel spacers, Is the a washer between the speedo drive and the chain adjuster? Also is there a gap between the sprocket and the hub, I'll post pics to help with my description.

Thanks, Mark

Snorton74 · Aug 30, 2015

I know very little about the MK3 wheel setup but here's the exploded view... Also I seem to recall LAB and others confirming a space between the hub and sprocket.

L.A.B. · Aug 30, 2015

MS850 said:
I have a question about my '75 MK3 rear wheel spacers, Is the a washer between the speedo drive and the chain adjuster?

Yes.

MS850 said:
Also is there a gap between the sprocket and the hub,

Yes, here is a recent thread on the same subject: cush-drive-problem-mk3-t23018.html

MS850 · Aug 30, 2015

L.A.B. said:
MS850 said:

I have a question about my '75 MK3 rear wheel spacers, Is the a washer between the speedo drive and the chain adjuster?

Click to expand...

Yes.

MS850 said:

Also is there a gap between the sprocket and the hub,

Click to expand...

Yes, here is a recent thread on the same subject: cush-drive-problem-mk3-t23018.html

Thanks for the quick response,
the reason i asked about the washer between the speedo drive and chain adjuster is that the speedo drive rotates when wheel is turned, my experience with ie Honda is once the wheel axle is tightened the drive does not rotate. Wasnt sure it was normal.

thanks Mark
Roseville Ca.

L.A.B. · Aug 30, 2015

MS850 said:
the reason i asked about the washer between the speedo drive and chain adjuster is that the speedo drive rotates when wheel is turned, my experience with ie Honda is once the wheel axle is tightened the drive does not rotate. Wasnt sure it was normal.

No, that isn't normal.

MS850 · Aug 30, 2015

L.A.B. said:
MS850 said:

the reason i asked about the washer between the speedo drive and chain adjuster is that the speedo drive rotates when wheel is turned, my experience with ie Honda is once the wheel axle is tightened the drive does not rotate. Wasnt sure it was normal.

Click to expand...

No, that isn't normal.

ummm, its not,
Ill take rear wheel off and look for the problem, It wouldn't be my first screw up, and i know its not the last.
any ideas?

Thanks, Mark

L.A.B. · Aug 30, 2015

Before you pull it apart, I suggest you check that the dummy axle nut is actually pulling down against the washer, and not bottoming on the shoulders adjacent to the dummy axle flats, in which case the dummy axle will not be pulled down tight even though the nut is tight.
This can happen if the outer washer isn't sufficiently thick enough.

Edit: The rear wheel diagram in the MkIII parts book isn't a particularly accurate representation (for instance, the seal, "item 25" is drawn on the wrong side of the bearing "23". Also "27" and "28" are drawn in the wrong position), the manual diagram (below) is more accurate.

MS850 · Aug 30, 2015

L.A.B. said:
Before you pull it apart, I suggest you check that the dummy axle nut is actually pulling down against the washer, and not bottoming on the shoulders adjacent to the dummy axle flats, in which case the dummy axle will not be pulled down tight even though the nut is tight.
This can happen if the outer washer isn't sufficiently thick enough.

To late pulled apart, not a problem i'm the middle of resorting the bike.
Im coming to the conclusion its the wrong washer, it appears to an aftermarket washer, so Im not sure its the correct thickness.
dimensions, (sorry im a metric guy)
out side dia, 38mm
inside dia 17.4 mm
thickness 3 mm

MS850 · Aug 30, 2015

L.A.B. said:
Before you pull it apart, I suggest you check that the dummy axle nut is actually pulling down against the washer, and not bottoming on the shoulders adjacent to the dummy axle flats, in which case the dummy axle will not be pulled down tight even though the nut is tight.
This can happen if the outer washer isn't sufficiently thick enough.

Edit: The rear wheel diagram in the MkIII parts book isn't a particularly accurate representation (for instance, the seal, "item 25" is drawn on the wrong side of the bearing "23". Also "27" and "28" are drawn in the wrong position), the manual diagram (below) is more accurate.

Thanks for your help, I used a thinner washer, and you were right the axle nut washer was catching on the dummy axle, wasn't fitting into the washer so it wouldn't pull the dummy axle tight.

thanks again, mark
(more to come on progress)

Madnorton · Aug 31, 2015

As you may have just found out, it is very important that you get the correct washer in the correct place so that when the dummy axle is done up the speedo drive is 'pinched' in the correct place, if not the drive will not last long. Look at the two washers and the drive when in your hand, read the manual and you will see that at first it does not seem right, but it is. This will also ensure that the cable will just clear the rear sprocket teeth, and that the inner diameter of the speedo drive is not tight against the sprocket.

Hope this helps other an explains why you where rightly concerned in the first instance.

L.A.B. · Aug 31, 2015

MS850 said:
I used a thinner washer, and you were right the axle nut washer was catching on the dummy axle, wasn't fitting into the washer so it wouldn't pull the dummy axle tight.

I was only partially right-as it's normally the substitution of a thinner washer in place of the original item that causes the problem-but if you are certain the nut isn't bottoming on the shoulder when fully tightened, then hopefully, all will be well.

Rear wheel spacers,

MS850

Snorton74

L.A.B.

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MS850

L.A.B.

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MS850

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MS850

MS850

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L.A.B.

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