It's almost certainly fuel starvation - check main jet clearance and accelerator pump. If this is only with the engine cold but it's OK when engine is hot, check the valve clearances. Actually, it's probably worth while doing that anyway - it may have been part of the reason it was neglected in the first place.
Will start with air filter as no carb slide, must be air flow that lifts reed valve to let in more fuel, new reed? Check manifold for leaks, compression test and valve clearances, would plug tell me anything.
Yeah, my mistake, talking about diagphram or membrane, no throttle slide as on old carbs, throttle just operates a butterfly valve to lets in more air, the fuel is regulated by a needle in a tube, this has a plastic air float that is attached to rubber diagphram, when throttle applied more air goes through carb, airfloat pushed up and more fuel allowed to.engine, if diadpram is too rigid with age or damaged it will not rise and not enough fuel will be drawn into engine, could also be clogged air filter, or valve adjustment or compression not drawing in enough fuel air, or leaky carb intake, or clutch gear related, im thinking
Air filter came off without a fight, was drenched in oil and oil ran out everywhere when i opened it up, hoping this was issue not sure how it got there, any ideas? WOULD LYING SCOOT on side do this,like when i welded in new belly pan, let you know if it runs better when i get it back together.
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