I've bought a few reg/recs from them for my classic bikes and as they're not far from me I"ve gone over to collect from their factory. Really helpful company and probably the place to buy std replacements but I don't think they do specials - it's more of a factory production line than a guy in a shed.

Probably a bit extreme for what you're after, but my mate mouse uses a car alternator to get high power output.

He's done this on two different bikes, both times using a belt to drive the alternator (though I think he originally experimented with a chaindrive with poor results). On his bmw he just welded a pully onto the rotor, and on the other bike (a gsx550) I think he extended the crank somehow through the sidecasing.

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UK to Mongolia 2009, on a DR350

Andy,I know it's not really what you are looking for but how about adding an extra battery in the chair?I realise that it is only posponing the inevitable,it will obviously discharge eventually if you use it enough.Can I ask what you are looking to power with the higher output alternator?

Many thanks for the useful links.

I already have an 85 AH battery in the chair, but it doesn't solve the basic issue that 27A output drops to under 20 at low temperatures, the battery loosing capacity as it cools in addition. 240W soon goes in heated jacket, visor, grips, headlight, GPS etc. and simply can't take the additional load of extra lights or a passengers heated kit if you want the starter motor next day (Oh why can't the Hinckley clowns fit a kickstart to RETRO bikes!). I calculate that I need to ration electrical power at anything under minus 10 if I want to remain independent for more than a few days. Ten minutes use of the tyre compressor means no heated jacket for an hour, which starts to get annoying and a sump heater would be a useful addition for the far north but would cut the heat ration further still.

(I carry chemical heat packs as a back up and substitute for the heated jackets 55W, which you can recharge on a camping stove, but of course you can only carry so many)

The pulley idea doesn't strike me as entirely practical as the alternator is on the right so the shaft would need to pass through the structure of the bike or the alternator would stick out from the motor. This is where BMW's and Urals are great, you just bung on a 70A VW job then work out where you'll keep the displaced petrol and CD changer! I don't really want a shaft passing out on the clutch side as this means oil seals. The sidecar wheel is another place to mount a pulley, but two alternators and two VR's gets messy.

One alternative would seem to be to mount a second standard rotor and coil and make a spacer for the cover, but I'm hopeful a simple rewind or new stator will boost the output by 10-25% which would be enough of a safety margin even at minus 20 but wouldn't rob too much power from the engine.

As a rather weird sideline, a solar panel is useful addition, adds about 5 AH a day even on a day like today.

Andy

I don't know how modular Triumphs are these days.When I had my Trophy pretty much everything would fit most every other model they made.Is there a higher output alternator on another Triumph that you could use?
Can you shave anything off your consumption by using LED lights for example?
Failing that,an even bigger battery in the chair or an extra solar panel?

With the BMW's airheads both of the larger capacity aftermarket alternators are larger than the stock one. But they are under the front cover and have the room.
Any aftermarket or rewound alternator will have to have a bigger gauge wire and a larger rotor and or stator.
Any extra watts, amps requires a bigger alternator.
If you can find the room for a larger alternator in the Bonneville I would think it could be done.

The stator is mounted inside the crank cover so there is room for a slightly bigger one. The rotor doubles as the ignition trigger so I am wary of messing with it.

The parts catalogue is definately something I'll try, it's just a case of sifting through the obvious choices to see if any part numbers match. The devious whatsits at the factory usually give the same part as many numbers as they have models, but the aftermarket suppliers usually can't be bothered.

Thanks Gents,

Andy