BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike Sponsor SteadfastCyclesBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorHepolite PistonsBritBike SponsorBritBike Sponsor
Upgrade to: Gold Membership | Premium Membership | Vendor Membership | Site Sponsor Membership
Words from our sponsors..
Vintage Motorcycle Auctioneers!
Vintage Motorcycle Auctioneers

CLICK HERE to see VIDEO
How the Electric Roller Starter works.

ORDER on eBay. CLICK HERE!
Buy your Electric Roller Starter here
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments.
Buy BritBike staff a coffee
Buy BritBike's staff a coffeeStill here since 1996 serving BritBike enthusiasts..
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Member Spotlight
Tribsauk
Tribsauk
Death row next in line norfolk
Posts: 461
Joined: July 2013
Show All Member Profiles 
Newest Members
Phil McClusky, 1957 Road Rocket, Payne, Mysticbus, T140v
11017 Registered Users
Top Posters(30 Days)
franko 136
koan58 69
DavidP 61
Popular Topics(Views)
1,148,972 mail-order LSR
a word from..
Forum Statistics
Forums35
Topics68,940
Posts690,948
Members11,017
Most Online14,755
May 5th, 2019
Who's Online Now
82 registered members (1957 Road Rocket), 2,226 guests, and 843 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Mk ll intermediate gear #785034 09/22/19 2:38 am
Joined: Jan 2014
Posts: 105
S
Samsmc1 Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
S
Joined: Jan 2014
Posts: 105
Can anyone tell me why Norton changed the cam drive intermediate gear for the Commando Mk lll? I'm building an engine from pieces mostly Mk lll, but with some other bits thrown in the pile I started with.
The cam sprocket is the same, therefore there shouldn't be an alignment problem for the chain.
Is there any reason I can't use the older intermediate gear assy?
Thanks
Sam

Support Your #1 BritBike Forum!

Check out British motorcycles for sale:
British Motorcycles on e-Bay UK
British motorcycles on e-Bay North America
CLICK HERE to see VIDEO
How the Electric Roller Starter works.


ORDER on eBay. CLICK HERE!

Buy your Electric Roller Starter here
Re: Mk ll intermediate gear [Re: Samsmc1] #785128 09/22/19 11:15 pm
Joined: Aug 2001
Posts: 1,348
D
Dave Comeau Offline
Crew Chief
Offline
Crew Chief
D
Joined: Aug 2001
Posts: 1,348
The MKIII is a very significantly different engine from all the previous versions. The crank is longer and the cases are wider. The timing chest had to be altered to keep the cam and oil pump in a similar position. A high skill or experience level is required to navigate all the variations of the norton heavy twins evolution. 1949-1975. I've worked on them all...


dynodave
BSA 3 1961-1963
Ducati 3 1992-2002
Norton many 1951-1975
87 Serv-Equip 100HP MC brake dynamometer,
Re: Mk ll intermediate gear [Re: Dave Comeau] #785139 09/23/19 12:35 am
Joined: Aug 2001
Posts: 2,823
R
Rohan Offline
BritBike Forum member
Offline
BritBike Forum member
R
Joined: Aug 2001
Posts: 2,823
Much chest thumping - but is there an actual answer there anywhere !?

Cheers !

Re: Mk ll intermediate gear [Re: Dave Comeau] #785180 09/23/19 11:27 am
Joined: Aug 2001
Posts: 1,348
D
Dave Comeau Offline
Crew Chief
Offline
Crew Chief
D
Joined: Aug 2001
Posts: 1,348
Originally Posted by Samsmc1
Can anyone tell me why Norton changed the cam drive intermediate gear for the Commando Mk lll?



Originally Posted by Dave Comeau

1.The MKIII is a very significantly different engine from all the previous versions.
2.The crank is longer and the cases are wider.
3.The timing chest had to be altered to keep the cam and oil pump in a similar position.

4. A high skill or experience level is required to navigate all the variations of the norton heavy twins evolution. 1949-1975. I've worked on them all...


This experience with enough research will show that
A. 21 years the NHT had a twin chain engine.
B. 4 years the NHT had a single chain engine.
C. The last year only of NHT (MKIII) had a different wider engine... see above.

Pretty clear to the most casual observer...


dynodave
BSA 3 1961-1963
Ducati 3 1992-2002
Norton many 1951-1975
87 Serv-Equip 100HP MC brake dynamometer,
Re: Mk ll intermediate gear [Re: Samsmc1] #785195 09/23/19 2:01 pm
Joined: Mar 2006
Posts: 4,248
L.A.B. Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Mar 2006
Posts: 4,248
Originally Posted by Samsmc1
Can anyone tell me why Norton changed the cam drive intermediate gear for the Commando Mk lll?


As explained by DD.


Originally Posted by Samsmc1
I'm building an engine from pieces mostly Mk lll, but with some other bits thrown in the pile I started with.
The cam sprocket is the same, therefore there shouldn't be an alignment problem for the chain.
Is there any reason I can't use the older intermediate gear assy?


The 850 Mk3 intermediate gear is thinner so there would be an alignment problem with the wider pre-Mk3 gear (and the timing cover wouldn't fit).

The Mk3 crankshaft pinion 06-5670 is also thinner.

https://andover-norton.co.uk/en/shop-details/16604/crankshaft-pinion



Last edited by L.A.B.; 09/23/19 2:01 pm.
Re: Mk ll intermediate gear [Re: Samsmc1] #785204 09/23/19 3:27 pm
Joined: Jan 2014
Posts: 105
S
Samsmc1 Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
S
Joined: Jan 2014
Posts: 105
OK - I understand what's going on now.
i had a reply in a previous post from Gregg stating that the covers were interchangeable but I didn't pay close attention to exactly what he said .

The MKIII covers are interchangeable with the older covers with a few mods (like the flat pump seal to allow the plunger to seat). I even updated a very early 20M3 Commando engine with a MKIII cover years back, though on that one I had to machine back the boss in the timing cover that supports the idler gear shaft.
.. Gregg *************************************************************************************************

Thanks
Sam

Re: Mk ll intermediate gear [Re: Samsmc1] #785261 09/24/19 12:30 am
Joined: Aug 2001
Posts: 2,823
R
Rohan Offline
BritBike Forum member
Offline
BritBike Forum member
R
Joined: Aug 2001
Posts: 2,823
Golly gosh we got there.
Extracting Norton info is sometimes a bit like like being a dentist ??

Re: Mk ll intermediate gear [Re: Samsmc1] #785330 09/24/19 4:38 pm
Joined: Jan 2014
Posts: 105
S
Samsmc1 Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
S
Joined: Jan 2014
Posts: 105
Rohan
I'm not sure that I agree completely with you analogy
Many times, we don't ask the proper question or read what was actually said like in my case with Gregg's reply.
thanks
Sam

Re: Mk ll intermediate gear [Re: Samsmc1] #785351 09/24/19 9:54 pm
Joined: Aug 2001
Posts: 2,823
R
Rohan Offline
BritBike Forum member
Offline
BritBike Forum member
R
Joined: Aug 2001
Posts: 2,823
I've used that analogy before, but I'd agree that there are lots of different scenarios and minor technicalities.
I've commented before though that Norton info (sometimes) seems much tougher to nail down.
But they were not a big volume producer, so maybe thats to be expected.
These forums sure fill a big need, so we do pretty good, mostly.

Re: Mk ll intermediate gear [Re: Samsmc1] #785353 09/24/19 10:33 pm
Joined: Jan 2014
Posts: 105
S
Samsmc1 Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
S
Joined: Jan 2014
Posts: 105
10-4 on filling a big need .


Moderated by  Dave Comeau 

Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Gold Membership | Premium Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.7.3