Lack of power after half throttle

[Kenweight]

Just rebuilt a series 1 with original points system etc.
Engine revs fine unloaded in neutral and pulls away in first and second etc from low revs okay. Then bogs down after half throttle. Any suggestions.

[MickYork]

Jetting may be too rich, blockage on air filter, choke sticking on, timing too far retarded.......

Try without air filter, disconnect choke/check plunger shutting off and not sticking........

[Kenweight]

Thanks Mick.
Checked timing last week and thats set quite advanced at the original 23 degrees. Been up and down on the main jet from 115 to 85 with the original 95 as a starting point. Even went smaller on main jet and that brought weak symptoms on. Plug is a nice chocolate brown. Could points gap affect . Presently set at 0.35 mm.
Will check choke tonight.

[HxPaul]

Dont know whats causing the "bogging" down,but in your last post you say that you have the timing set at 23 degrees.I would say this is much to far advanced for todays fuel,I have mine set at 17 degrees and I would say that anywhere between 17 and 19 degrees is safer.

[Kenweight]

Originally set it at 20 degrees and had the issue, was wondering if it was too far retarded so changed to the factory setting of 23, no difference. As you say all my other electronic ignition scoots are set at 18 degrees, so may change to there.