What about trying the Aspen fuel they sell for lawn mowers? Changing the fuel should help you prove where the problem is coming from.

Have a close look at this...

Can you take a picture showing all the wiring? If it rotates with the battery between the f terminal and the ground, it sounds like it's not wired up correctly internally. There must be some connection somewhere to the commutator for the armature to rotate - it sounds like you have the f terminal ...

Chris Sealy wrote: Thu Jul 09, 2026 3:37 pm Where does the black wire, which is connected to the D terminal, actually go to?

There should be two wires coming from the field coil, one goes to earth and one to the F terminal.

Then there are the two brushes - one is connected to the D terminal, the other to earth.

Individual armature coils shorting each other? Just thinking aloud, and not an expert here, but adjacent commutator segments shouldn't connect to each other. The armature is a bundle of coils, and each coil has a segment at each end, so each segment should show continuity to one other.

I think a lot of us are using DVR2 or V-Reg2 regulators with the standard C35SD generator. The secret is to have a big enough battery - mine currently has 19 Ah of battery capacity; I ran it with 12 Ah for a while and had many more problems with misfires or poor starting. They don't like towns!

Excuse my ignorance - I don't have a KH - but is the AR unit stuck?

Alternatively, has your needle and jet become very worn?

And lastly - not a joke, I have done this much to my own embarrassment - has your main jet fallen out?

Hello Simon,
Yes, the cylinder has a fixed head. As it has a flange & studs for carburettor mounting it will be after 1927. It has a good standard bore & no fin chips. The guides are good, but a new set & valves here too, good quality issued by A.o.m.c.
Regards, John.


I'd like those please ...

John Hill wrote: Thu Jun 25, 2026 7:54 am Hello, ex AOMC member still has for sale :-
Good standard bore cylinder, (flanged for carb) no chips.
4 new valves.
2 new guides.
New rings.
Crank assy. fitted new Alpha. Not running true.
£80. Can deliver Kempton, Ham Street, Founders Day.

Fixed cylinder head? Any idea what year?

Looks like a Burman/Ariel clutch with added lightening!

Here's what they normally look like...