That would be my worry. The starter engages through a clutch of sorts but having it engage with the engine at anything above a fast idle is not a good idea.
This is a long shot Tony but before taking anything to bits check the side stand switch because that little micro switch is in all the crap off the road and the chain and can be the cause of a lot of starting problems
I did tell you the easy way....a misbehaving relay could give this kind of problem equally. I had a similar experience with the indicator relay last year, was absolutely certain it was a loose fuse because every time I pulled the fuse and put it back it seemed OK. Now I wonder if removing the power allowed the relay to reset in some way. The reason I asked if the bike worked normally once started was precisely because of the danger of the starter motor spinning up when you pull the clutch in. So, once the bike has started does the headlamp come on as normal?
A breakthrough, I thought to myself what changes overnight and bingo, when I turn the bars to the left to put the steering lock on it malfunctions and starts on clutch pull, straighten the handlebars as I did last night to move it and it works correctly on the starter button. Repeated it 4 times, full lock to the left starts on clutch pull, handlebars straight starts on button. I can only think something in the wiring in the headlamp is shorting, don't think it is the starter switch anymore as when I did this the starter switch was hanging off as I'd taken it off the handlebars, so don't think the starter switch was impacted by handlebar movement. Looked in the headlight and can't see anything obvious, might still be the starter button cable moving but unlikely as hanging free, so maybe something the other side of the connector it plugs into in the headlight. Anyway, far too electrical for me. Might have to see if I can get someone to come out and look at it.
Triumphs are not unknown for giving issues due to short cabling, particularly around the steering head. Since you have the thing apart, it may be worth disconnecting the RH switchgear and removing from the bike and check it closely for any nicks in the sheathing. And is the grommet where it passes into the headlamp shell in good order?
It all looks fine, can't see any obvious damage anywhere, grommet looks good but not much room, would be a nightmare trying to feed out the existing starter button cable with the connector on it. Bit messy looking but all electrics look messy to me. If I turn handlebars to the left, switch ignition on and pull in the clutch the headlight dims, bike starts and headlamp comes on full. I'm too chicken to try pulling in the clutch again though.
Have you checked the wiring around the headstock as MightyBoosh suggested? Pull it away and inspect behind the cabling where it rubs against the frame headstock.
I gave it a quick check but very difficult to see it clearly. The wiring from the starter switch just goes directly into the headlamp and doesn't really touch the headstock at all. I'll give it another look in the next day or 2. The starter switch itself is hanging loose off the handlebars and when I turn the handlebars it doesn't seem to move the cable at all, but there must still be some slight movement in the grommet even when hanging loose. Thanks
The wiring from the starter switch goes into the headlight then connects to what? The wiring that passes the headstock?
The things we do for England, and less l just had a quick gleg in my headlamp shell and this is what you will probably have... Connector for right side switches splices into the Y shaped taped loom you can see here That loom finds its way nicely clear of the headstock, to be fair. But then it passes a bit close to the fuel tank. Is that a possible?
Thanks for all the advice. It does go into another connector and I did check that and it also looked ok. I'll give it a more thorough look in the next day or so, work permitting. Cheers
