Bought Frankenstein bike, engines been stripped and reassembled, carb cleaned still won't run

[Keep]

Hi, this is my first post on a forum, i recently bought a 140cc "demon X" pitbike, it has had a full engine rebuild by a semi skilled mechanic who i trust to have done a good job, i have cleaned the carb out and it has all been put back together. I started all the work because it was running rough, it would get to full throttle eventually but you would have to keep letting off the throttle to get it there, and it feels like it's bogging out all the time. Now that the works been done it started thismorning but i can't get the thing to start again. It has a 26mm Molkt carb on it and i can find out the jet sizes when i get back to the garage, i have took the carb to bits again because after i last gave it a petrol bath it ran well for less than a minute, but it did run, everywhere I look it says to run the bike for 10 mins or so before tuning it but i can't get the thing running to do that, any ideas please, if more information is needed i can find that out and get back to you, spent too much on this thing already to give up now, kinda wanna see it through and get it running instead of scrapping/selling it.

 

[AntNZ]

save yourself some trouble and chuck the molkt in the bin!!
grab an oko26 flatslide if you like lightswitch type power, easy to work on and tune, heaps of info for all engine sizes with this carb in the oko thread....
if its a roundslide you're after then the cheap fakuni's seem to be popular..

have you checked your fuel tap for blockages?, spark plug?, valve clearances???, just a few suggestions.

good luck

 

[bmxreeves]

Like said above, check valves. Is your ignition timing right? What about your cam timing?