Electric start conversion

RGM are working on one but that's been a long time. For the MK2a you need to consider the black box airfilter which may clash with the CWN version.

If the airbox is gone then the CNW is the better engineered of the 2 available, but both will work. 

Correct me if I am wrong here but I think you can buy CnW parts from Holland avoiding the killer import tax from the USA.

I have used CnW parts on an 850 rebuild and have to say the quality of their parts is outstanding.

Someone asked a similar question recently in one of the forums.

Here is my opinion - truth is they are both superbly made in terms of quality. And both companies are great to work with.

Each have their benefits and drawbacks:

Colorado Norton Works

• + comes with a primary belt drive
• - you cannot use the standard air filter (cNw were looking at a building a cut down ham can which maintains a classic appearance)
• + it uses the standard alternator stator (which opens up your options for charging)
• + wound field motor means positive or negative earth compatibility
• + off the shelf (Harley style) motor with solenoid engagement

Alton

• - transmission of starter torque is solely via the alternator rotor woodruff key
• + maintains the original air filter
• - comes with it’s own alternator (which limits your choice on charging solutions)
• - permanent magnet motor means a modification (or Alton recommend they provide a different unit) to support negative earth installs
• - bespoke motor using plastic shear pins to protect against backfire

Most people’s choice is driven by cost vs geography:

• if you are in the US you buy the cNw unit
• if you are in UK or Europe you buy the Alton.

Thinking of it like this, it means the pricing is similar.

I bucked the pattern, and got the cNw kit, and am really happy with the quality of the kit - I like Matt’s stuff. It’s a project bike, and I don’t have the air filter to consider, plus I was in the market for a belt drive too.

Either way, I feel we’re blessed to have two great choices!

Two other options were available:

Old Britts - http://www.oldbritts.com/ob_3860.htm

• This was a limited run,
• Fred & Ella are sadly retiring
• I this is no longer an option.

Quiet Power Drive (QPD) - http://www.quietpowerdrive.com/QPDhtm/QPDhome.htm

• Bob ‘Ozzie’ Oswald is also in the process of retiring
• I believe he worked with Kenny Dreer on the electric start for his concept 880 - which was Kenny’s evolution of the production Commando.
• I worked with Bob on a belt drive project, and found his communication and timescales incredibly frustrating.

​​​​​​​Both of these systems were nice as the starter drove a crown wheel attached to the clutch basket, which made the entire setup low profile and unobtrusive.

The compulsory belt drive with the CNW system is a negative if you prefer a chain drive as some people do (well I do!).

agreed, and do feel free to ignore my post, as I said it's just my opinion :-)

Tony, I have gone the DIY route, KLF300 starter with internal planetary gears and a GL1100 sprag unit. Problem is it won't work with a belt drive as the sprag unit needs oil.

The Old Britts ring gear is a special due to the diameter not matching the Harley but the gear profile is a standard used on a lot of starters so can be ordered from a gear cutter once you know the profile, buy the starter and then measure the gear to determine profile.   

Interesting John, have been looking at using similar, Honda, starter but on the timing side but worried that the crank drive gear would not be up to it. Article in Roadholder by a chap looking to do similar on a Dommie looks interesting and would like to see how he gets on.

Am favouring using the the starter to drive the clutch particularly with a belt fitted.

My clutch drum is 185mm dia, a few ring gears for Harleys look to be about a right diameter so was wondering if Old Britts used one of them and modified it, but which one?

Mine is driveside, Norton tried the timing side but something was breaking so they dropped the idea in 72 and started from scratch again to give the MK3 design. Triumph tried timing side too and chased breaking components by adding strength to each broken part until the crankcases broke themselves and went no further.

I reduce the triplex sprocket to duplex and use Merc duplex timing chain as a primary chain, use the thinnest alternator which is the 10.5A 3 phase and with some other tweaks this gives space for the GL1100 sprag unit to run on the driveside of the crank. The starter motor sits in the magneto position as per MK3 and Alton and a chain drive runs to a sprocket behind the primary and then a shaft runs inside with another sprocket that runs a chain to the GL1100 sprag unit. I used the Honda Africa Twin and Polaris 700 twin starter setups as the basis for the starter gearing ratios. It easily spins the 750, yet to try it on an 850.

The only original parts I modify are the inner and outer primary cases, easily bought 2nd hand if the changes need reversing.

A couple of thoughts on Grants excellent summary above

Alton - the woodruff key shouldn't be relied on for load transfer. The nut on the crankshaft needs to be torqued, and to my mind retorqued after the first good ride, so that all being compressed together transfers load between elements. Any relaxation of the sprocket on its taper will affect that compression hence my thought on retorquing. Just my opinion of course.

Alton - changing polarity. No too difficult for any who are handy with spanners, Alton can provide a nice clear instruction sheet, but they recommend returning to base rather than DIY.

The Harley starter is a standard Nippon Denso offset gear reduction unit which is found on many, many vehicles over the last 30 years. Usually it is 1.4kW, but there are 1kW units. As it is series wound it doesn't care about polarity. The only differences between different models are the starter dogs and the casting which bolts up to the bellhousing. Crude violent things.

I am hoping that modern electronics will allow me to control the torque and avoid the problems that Norton and Triumph struggled with. As an example I can apply gentle torque and just wait until it reaches TDC, not something that Norton could have done in the '70s.

I am only aiming for a low compression 600cc, not a high comp 750cc, and so far the development is going well. The mechanical side works satisfactorily, but I have a lot of improvements in mind.

I knew about the Bonneville, but I only learned that Norton had tried this in the last week!

Just for info, here a drawing from the Norton Villiers patent of the unfortunate starter-to-be:

Just a note for any potential electric start conversions - see end Note.

My 1978 late production run Commando Mk3 is one of the last 300 made.

R/H switch gear was updated for this year and used Andover Norton part number:

12 - switch r.h., ES (60.7328) (06.5929)

in stock part-no: 60.7462

This is the exact same switch gear that was used for the Triumph T140e (1979-1983). Andover Norton part number:

18B (E-Start Models) switch r.h., ES (60.7328) (06.5929)

in stock-part-no: 60.7462

The 13mm bore size updated replacement unit for the Norton is expensive, but it will improve brake performance and it will also maintain the original look of the standard 5/8” bore size unit. Andover Norton part number:

7B (13mm gloss black)

FRONT MASTER CYLINDER ASSEMBLY C/W LEVER 850mk3 (13mm bore) PAINTED GLOSS BLACK

in stock part-no: 06.5742/13/1   £319.14

Interestingly Andover Norton offer both a complete unit, as above but also a full body unit for non Mk3 Commandos at a reduced price:

8 (13mm Conversion Kit)

FRONT MASTER CYLINDER BODY C/W MIRROR MOUNT (13MM BORE) C/W INTERNALS 

in stock- part-no: 06.1939/13  £239.70

So instead of reviewing replacement master cylinders for the Norton, I looked at what was available for the Triumph.

The standard Triumph T140e Master cylinder is a 13mm bore size, this is an Andover Norton part and fits directly onto my Commando switch gear.

Andover Norton part number:

1 master cylinder assembly

in stock- part-no: 60.7163    £249.12

I purchased this unit from Classicbikeshop LTD for £165

So the new units bolts straight on. 

It is a standard Andover Norton part and was half the price.

Note

Any conversions of pre Mk3 Commandos to electric start may well end up with the latest switch gear (as standard on my Commando).

So consider your master cylinder options at the same time.