Voltage Drop on Starting

[Grahamm]

I'd be more suspicious of the sparks.

The thing is, at times it can be very sluggish to turn over and really struggles.

Regarding the sparks, as mentioned earlier,  I've tried checking the plugs (well, the nearest one on the right hand side of the bike) and although they're fairly old, it didn't look faulty.

I did think about trying to check the resistance of the Spark Plug Cap, but although I could get it off the plug, the Haynes manual said "unscrew the cap from the HT lead", however it seemed to be directly moulded onto the lead somehow and I didn't want to damage it by using brute force.

Does anyone know if I can just uncrew the plug cap or is it actually directly moulded to the HT lead?