A10 having difficulty running over 3/4 throttle.

[Swarfcut]

The fault can only be one of three possibles.....Mechanical, Electrical, Fuel.

I'd check the tappets for a start, too large a gap will retard the valve timing so it starts and runs OK but valves will be opening just that bit later and closing a bit earlier and so stifle full throttle performance.  Costs nothing, could be the answer.

 Swarfy

[owain]

I took apart the magneto, visually the only thing I could find was a smear of carbon on the earth slip ring (not 100% if that is the correct terminology but I hope it's understandable). Hoping that I had finally solved the issue, I reinstalled the mag and gave it a test ride...only for the same issue to happen again.

I think the the next stage will be to check the tappets. Checking the plugs is also a good idea but in practice is difficult to carry out as this usually occurs when riding on the motorway.

I am really hoping that this can be resolved soon as a Honda replacement is looking more appealing by the day!

[berger]

i know what i would do but this is me , from past experience with brit bikes and concentric carbs and slides with slight slop i would beg borrow or buy a second hand monobloc jetted to your bike model and try that, buts that's me.

[CheeserBeezer]

That armature has been restored so it should be OK. However, only an exchange armature would tell you if the armature is the culprit as you need to go further than a visual inspection.