Mk3 changes from 74 models

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cam bush???????????

I had to check (at AN) the early SLEEVE GEAR bushes are .88" long and they are actually still available. :shock:
The MKIII gearbox sleeve gear bush are 1.2" long.
For the last 27+ years we would put 3 early or 2 late bushes in a sleeve gear. nothing new here....
 
Yes, cam bush.
From my reading there are six different cam bushes from the Atlas thru to the MK3. The first five are listed as singles both sides , but the MK3 uses two shorter bushes on each side.
Can't say for sure that it was an improvement, definitely a change, no doubt intended to be for the better.

Glen
 
Not sure if these have been added -

Front master cylinder - different to previous model
Caliper - not sure when it changed, but he MK3 uses the chamfered caliper.
O/S lower rear suspension bolt.
I have also seen a plate backing up the seat lock, though never found a part number for it.
Outer chaincase to accept starter bush - removed on later models I believe.
Quadrant roller, and quadrant aperture in inner cover.
Front caliper scraper plates, though not sure when this was introduced.
Front mudguard.

The top yoke was changed allegedly after the MK3 was introduced to 'clear the interstate tank' but seeing as the interstate tank had been about for years in the larger wide design, this does not add up, and all the MK3's I've seen have the same the top yoke.

If you read the workshop manual, it also appears to indicate that there are different versions of crankshaft fixings for the MK3, by the description of the crank nut and studs that are described, though I believe only one version of crank fixings was ever used.

Had they not gone into administration there would have been other changes in the life of the model as well, in the short life of the MK3 some parts themselves underwent many changes as well.
 
Madnorton said:
O/S lower rear suspension bolt.
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Yes, but it was only one of a number of Mk3 rear disc brake assembly components as just about every part of the Mk3 swinging arm, rear wheel assembly and brake that were "Mk3 changes from '74 models".


Madnorton said:
Quadrant roller....
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Again, just one of a number of gearbox parts that had to be altered/added in order to convert the gearbox to left-foot change or were you suggesting there was a change made to the 'spherical' Mk3 roller during Mk3 production? And if so, what's the difference?

Madnorton said:
....and quadrant aperture in inner cover.
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Again, what was the reason for the apparent difference?

Madnorton said:
Front caliper scraper plates, though not sure when this was introduced.
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The 065143 scraper was introduced during '73.
A caliper with the scraper attached (065173) was also introduced at that time and appeared to last into Mk2/2A production as that's the caliper part number listed in the 2/2A supplement and the scraper and screws are also listed separately, however, by Mk3, the calipers (front & rear) appear to have reverted to the original 061926 part number, the scraper and screws are not listed in the Mk3 parts book.
 
Sadly, we will never know why the aperture dimension was changed - it may have nothing to do with the MK3 (unless they envisaged getting another pair of cogs in there) and so may have been just an opportunistic moment to introduce it, like the inner cover nut spot faces for washers which in any case is good engineering practice, but nothing to do with the MK3. As far as I know, for the roller it stayed the same throughout the life of the MK3, strangely the fitting of the roller, contrary to the manual, I have found may fit once the inner cover has been fitted, on my late MK3 it won't, but on my earlier project MK3 it fits, as I found when it fell out - what the difference is I don't know but will look closer when the late MK3 is refurbished later this year.

It seems the MK3 was designed on the back of a fag packet with magic marker and a bucket of Tipex, still a good piece of kit though.
 
What surprises me is the effort that was constantly going into redesign of the Commando even as Rome was burning. There were lots of changes /improvements with the earlier models as well, but the biggest redesign has to be between the Mk11 and Mk111 850s.

Glen
 
Madnorton said:
Sadly, we will never know why the aperture dimension was changed - it may have nothing to do with the MK3 (unless they envisaged getting another pair of cogs in there) and so may have been just an opportunistic moment to introduce it,
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I wasn't aware that it had been altered at all. Perhaps some of our forum members have some spare early inner gearbox covers they could measure?


Madnorton said:
As far as I know, for the roller it stayed the same throughout the life of the MK3, strangely the fitting of the roller, contrary to the manual, I have found may fit once the inner cover has been fitted, on my late MK3 it won't, but on my earlier project MK3 it fits, as I found when it fell out - what the difference is I don't know but will look closer when the late MK3 is refurbished later this year.
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I'm not sure there is a difference, the spherical roller should fit with the inner cover in place (unlike the earlier parallel roller) and it fits that way on my reasonably late (7 - 75) Mk3.
 
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