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#788641 10/30/19 7:25 pm
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Samsmc1 Offline OP
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I've stepped into another puddle and need help. I thought that the Mk III intermediate gear was easily recognizable by it's tapered shape on the backside.
If I'm correct, then I should have the correct gear on my engine - problem is the cover will not fit up all the way suggesting that I may have a gear that is too thick.
Does anyone have a known correct gear that they can measure for me at the center?
Same with the pinion gear, it's supposed to be thinner also. Can anyone give me a measurement of it's thickness?
Thanks
Sam

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https://www.oldbritts.com/06_1077.html
"The main difference in the gears is the thickness of the Intermediate gears. The MK3 gear is approximate 0.444" thick where the pre-MK3 gear is 0.5" thick."


https://www.accessnorton.com/NortonCommando/crankshaft-pinion.19148/#post-286113
"68-74 commando NMT2035 same part IAW parts books
all .564" 14.32mm

1975 MKIII because of wider cases therefore narrower gear 06-5670
.494" 12.54mm"

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Samsmc1 Offline OP
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It appears our limey buddies got me again!
I had the right intermediate and pinion gears in both of the fresh Mk III bottom ends I'm assembling.
One has the later bolts and washers holding the pump in place and the other has the older style stud and nut arrangement.
When I pulled the lower nut or bolt from the pump, the cover fit just fine.
I placed dye on the case near the pump bolts and that told the story.
This cover is a N.O.S. cover (not a repro or pattern as the Brits call them) I've had in stock for many years.
I don't have a used cover for either engine, so I didn't have one that was known good to start with.
Once I ground about 1/16th from the inside of the case, problem solved.

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Crew Chief
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Originally Posted by Samsmc1

This cover is a N.O.S. cover (not a repro or pattern as the Brits call them) I've had in stock for many years.
I don't have a used cover for either engine, so I didn't have one that was known good to start with.
Once I ground about 1/16th from the inside of the case, problem solved.


Either engine???
You may have just "fixed it" so the next guy will wonder who worked on this?
What is your engine series you are assembling and from what series is your NOS cover? Are they even normally compatible?
NHT timing chest covers
Are you saying you have a MKIII engine MKIII oil pump with MKIII style hardware with MKIII timing cover and gasket and there was a "crash" in the blue dye?


dynodave
BSA 3 1961-1963
Ducati 3 1992-2002
Norton many 1951-1975
87 Serv-Equip 100HP MC brake dynamometer,
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Samsmc1 Offline OP
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Yes - I had the correct gears and cover for the Mk III. It was a new old stock cover that had never been mounted.
It clashed with the bottom oil pump bolt or stud / nut assy.
I thinned the lower part of the case a bit with a Dyna Brade file and re-blued the cover - no more marks in the cover and everything fit up.

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Crew Chief
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Originally Posted by Samsmc1
Yes - I had the correct gears and cover for the Mk III. It was a new old stock cover that had never been mounted.
It clashed with the bottom oil pump bolt or stud / nut assy.
I thinned the lower part of the case a bit with a Dyna Brade file and re-blued the cover - no more marks in the cover and everything fit up.


Thanks for the reply. It makes me wonder if norton being in the last year being in bankruptcy had bad parts coming out the back door?? This after all was the last year but the first and only year for this new version. I don't really count 76 and 77 as full model years but just final assembly and disposal of the bankrupt assets.
cheers


dynodave
BSA 3 1961-1963
Ducati 3 1992-2002
Norton many 1951-1975
87 Serv-Equip 100HP MC brake dynamometer,

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