EL011 ELECTRICAL

I'm trying to get my Thruxton back on the road. One of the previous owners apparently converted the dynamo to 12V, with some sort of regulator mounted on the rear mudguard. This is sealed, has no identifying marks and isn't working, ergo my desire to convert to a 12V alternator.
Can you advise me on this venture? Would like to maintain the original appearance as much as possible. I'm not especially adept mechanically (or electrically!), so a "drop in" conversion would be my first choice. - Paul Rochmis 16/9/2002

The regulator sounds like a "JG" electronic unit. They normally work very well, unless you connect the battery the wrong way round, when they die. Unless this has happened it is most likely just a bad connection or the dynamo has a fault. Some of the other "Electrical" Q&As discuss the subject.
Most alternator conversions end up looking pretty non-standard, unlike the JG conversion that keeps the original appearance of the dynamo and you can hide the JG. The oldest established conversion is from Criterion (see contacts), but this is clearly visible. I believe there is an alternative called the "Alton" but I do not have contact details for a supplier - you may find them with a web search. I think it even looks like a dynamo.
I think your easiest and neatest solution might be to send your dynamo and regulator to someone like Dave Lindsley or FTW in UK, or their equivalents in the US, and have them overhauled. Once done they pump out 12V very reliably, especially if you use the club conversion to a toothed belt drive. - TW 16/9/2002

I'm considering a 12v and electronic ignition conversion for my VM. Which kit do members recommend? I'd like to know about ease of fitting, change of appearance from original fit K1F and dynamo, reliability and cost. -  Dave Reid 18/9/2002

I have just taken delivery of an `ALTON` alternator from GROVE CLASSIC MOTORCYCLES It does indeed look very similar to a standard dynamo, have not tried it yet as the rebuild of my No 2 Venom is going quite slowly at the moment. - Eric Cox 25/10/2002

I fitted an ALTON alternator to a Thruxton a few years ago in order to have adequate lighting in today's traffic as a safety precaution.
Great result indeed.
Besides the outside dimensions of the unit are identical to that of the original dynamo.
The only weakness I find is that it is very demanding on the belt and I regularly have to replace it. But it may simply be that the belt does not like too much the oily mist in which it operates.
A tooth belt conversion should be explored to resolve this minor drawback. - Gilles Glachant 21/11/02

I am in the early stages of running with an Alton generator and a bespoke Interspan electronic ignition kit on my Clubman Venom. Anyone any experience of either of these things ?
Alton - no comms yet except it looks nice, whacks out a lot of power, and probably consumes a few bhp too. Service from Alton excellent. I am modifying the club toothed belt drive to fit since the std. belt slips a little.
Interspan - all seems ok so far except difficult starting initially (I traced that to a bad earth - good earth is critical to the Interspan (and I guess most electrics) so I used (a clean bit of the) crankcases not (powder coated) frame. Also it seems any p.d. between different earths in the system affects this thing too. But its OK now. I can provide some details of this as I use it more - I had the system built to my spec - i.e. fast road use, sensible advance curve etc giving full advance at sensible revs etc.
I had a very good mag (K1FC) until it 'went bang' last year, so performance and starting was always good, but so far Interspan is an improvement I believe, esp at sub 40mph speeds. Not so much difference mid-range or top end though - but its early days yet. 
Follows the basic electronic ignition spec arrived at after discussion with Fred at Interspan for a fast road bike:
12v ECM Type 2000 Mk9
DC supply range 5 to 16V for full output (i.e. turning the lights on shouldnt kill it)
Full advance @ 3000rpm
dynamic advance 30 degrees
full advance 38 degrees
All necessary components contained in one box (neat). Replacement mag housing and precision trigger assembly are separate items obviously. HT lead and cap supplied with the control box. Clear instructions/wiring diagram etc. and also excellent help/advice over the 'phone.
Expensive - yes, but in going for electronic I decided on a kit with a tailored advance curve having seen the transformation such a device has made to friends Clubmans Goldie.
Worth the money ? Debatable in real world terms - the K1FC was a bloody good un before it packed in, but if I'd been suffering from an 'ordinary' magneto I'd have probably been more pleased. But it is improved at town speeds. Starts first time now Ive got the earths sorted out.
I'll report through the year as things develop/the miles rack up. - Andrew Barnes 21/1/2003

Has anyone got any feedback on the effectiveness and ease of converting the club toothed belt drive to run his Alton Alternator? - Ian Medd 14/5/2004

I bought an Alton a few years back for my VMT when I decided to go to electronic ignition and a GP carb set-up (wanted to make sure of a good modern 12V supply that looked right as well)
Initial experience - well it takes a lot of turning over, such is the power of the thing (some people have estimated it absorbs 2-3bhp). But it certainly delivers, and Paul Hamon at Alton is a pleasure to deal with. Looks good too, at a casual glance it looks just like a dynamo, and even bears closer inspection.
In view of the effort needed to turn the Alton over, I figured that fitting a toothed belt would be a good idea - there was some indication of the standard belt slipping (but I wouldnt say it was an essential fit by any means).
The Alton shaft (and thus the pulley) are not on the same taper as the standard Miller dynamo set-up - so Alton supply a special pulley to suit for the standard velo V-belt (included in the price).
The toothed belt drive that was supplied by the brilliant Velo OC spares scheme was only available for the std Miller dynamo in those days - so the front pulley needed to be modified to fit the taper of the Alton - a simple engineering job, just bore centre hole out to size. I believe that the Velo OC now supply the toothed belt drive with a choice of front pulley - either for Alton or std Dynamo
But Alton itself - I can recommend both the kit and the Company - I've had one failure - replaced free of charge - and the second one has lasted for a long time - all sorts of riding/abuse. But then my clutch hasn't needed adjusting for 15K miles, so maybe my Velo is a bit odd...! - Andrew Barnes 14/5/2004

My experience is 100% in agreement with Andrew, including a quickly replaced failed unit ironically while in France. I too fitted the club belt kit as the V belt was slipping (an easy mod to a mag toothed pulley). My only other comment is that the Alton is a little noisier than a Miller dynamo.- Dai Gibbison 14/5/2004

In the VSL spares list the pulley listed with a 13mm shaft, which is presumably the one for the Alton, is a 36T.
The pulley supplied with the alternator is SMALLER than the normal small size pulley I was using previously on a dynamo. i.e. the equivalent of a 32T.
Dimensionally it gives a running speed around 1.39 x engine speed (80mm/57.5mm).
Although I haven’t contacted the manufacturer yet, I suspect that using the club pulleys will lead to a significant reduction in output.
Do you have any idea on why the larger size is supplied for the Alton? - Ian Medd 2/6/2004

The VSL388 pulley should have an attached comment of "Keywayed shaft for Alton alternator and Lucas Dynamo" (both use a 13mm parallel shaft). The Sales List will be updated.
Regarding the size of the pulley, some people have happily fitted the VSL388 36T pulley to an Alton with no reported problems.
It is what I would do too, since alternators give good wattage at low revs and will last longer and absorb less bhp if they turn at 1/8 lower revs, which is all the difference using the larger pulley will make. It would be a while before VSL could get a batch of 32T 13mm pulleys made, but by all means put your requirements to them if you do want the 32t and can't machine one of the taper bore ones yourself. - TW 15/6/2004