Honda CG125-J Brazil, Carb Issue or what?

[atha]

Hi everybody,

A few months ago I bought myself a Honda CG 125-J Brazil.
It is in pretty good nick, always starts first time and has less rust on it than most people would expect after 22 years.

There is just one thing which starts driving me mad and I would be really glad to get some advice from your side as I am completely new to bikes and mechanics and might start eating my Haynes manual if it does not get better soon .

The problem is that I cannot run the bike without the choke open.
I have tried to adjust the idle speed but this did not seem to help.
It got a little bit quicker but never quick enough to make it possible to run the bike without an open choke even though the engine was warmed up properly (5min+).

I took the carburettor apart and cleaned it and made sure there is no dirt and no blockages inside. This did not help either.

Checking the spark plug showed that the engine seems to run 'rich' as the spark plug looks black and sooty.

My next thought was that it might be an air problem - probably to little air in the mixture.

I ran the bike with the air box cover screwed off to see if the problem is the air filter but this did not change anything either (might get a new airfilter anyway).

There might be an air leak in the carburettor/ inlet stub somewhere as one rubber seal in the inlet stub looked quite worn (turned it around for now and rubbed some oil on it for a better seal).
I am currently looking for a replacement but it does not seem to be very easy to find one.

It would be great if somebody had some advice on where to get a carburettor gasket set + inlet stub rubber seals from (checked ebay and some bike parts homepages but wasnt really statisfied).
I also heard of some kind of 'liquid gasket'. I am not sure about the quality of this and would appreciate some advice in case sb has experience with that stuff .

I am also looking for general advice because I really do not know what else to check/ replace. Maybe somebody recognizes the issue or does have an idea what else I could have a look at?

The only thing I can think of at the moment is an air leak but I might be missing something...?


Thank you very much for your help and I can upload pictures if you wanted .

[Billriach]

Points to a major air leak on the induction side or carb blockages
____________________
Honda CD185T
Honda CBR 1000F-M
Honda CB125 TD -E Oh, and my Daughters Sym Simply 50cc scooter (til shes 17)

[Billriach]

Check the induction stub for cracks / splits they go rock hard, I use a mix of instant gasket / grease to seal them.

Listen for whistling noise on idle which would indicate an air leak
____________________
Honda CD185T
Honda CBR 1000F-M
Honda CB125 TD -E Oh, and my Daughters Sym Simply 50cc scooter (til shes 17)

[atha]

Thank you very much Brilliach.
Tried a few different things out and in the end it was a combination of wrong valve clearance (far too tight) and also somebody had tampered with the throttle valve assembly.

Thanks