new member with honda cb125s / 65.5mm big bore kit

Hi everyone I'm mark from England iv just recently restored a 1975 cb125S...






However I'm having running problems. The bike starts but runs like rubbish pops bangs misfires through carb etc etc. The engine is a cb125s with a 65.5mm barrel and piston


And I'm using a mikuni copy 28mm carb with a 105 main jet and 38 pilot with 2.5 turns out of the mixture screw.. the engine ignition/cam and points setting's are set to factory settings...

I'm struggling to get the bike running nice and safe and would like some advice if I'm using the right size carb for the barrel etc etc any help would be great..

Some youtube links of here running .. please copy and paste..

Is it possible the timeing is out somehow?

It is going to run horribly with no muffler. It won't idle right if at all and have no low end power.

Make sure timing isn't 180* out.

cam timing?

That's an amazing transformation and a ton of work. Nice job!

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