just got hold of a honda tl125, but it does not run well, starts up without choke, but ticks over nicely from cold and revs well enough, but then once warm is all goes wrong, the idle revs increase when blipping the throttle, it starts to bog down and does not like being under load and then is hard to start, the plug is not sooty,  initially i thought condenser so i have replaced this and the coil but its still does it, the points seem in good order and timing seems right. any help appreciated

Air leak in carbie area ...google check carbie air leak...very simple test

i did check for an air leak but nothing was obviously changing the engine speed when checked