Motorcycle Forum / Country Specific / Classic (UK Group) / August 2007

Well, as ever, there were a few bodges. It seemed to be running leav,
and I could see a small gap between carb and inlet manifold casting, so
removed the carb. Someone had put in an O-ring that was too thick, and
hadn't bolted up the carb tight.

So I bolted it up tighter and the throttle slide seized.

Ah - the O-ring is too large to compress, and I'm distorting the whole
carb. Eek. Oh, and the manifold gasket is missing.

In my boxes, locate a handful of CB125 manifold gaskets, select one,
plus one smaller O-ring, and refit carb. Oh, and replace the missing
hose clip on the air filter attachment, to get a decent seal. That's
better.

Oil, filter cclean, tappets. Camchain... well, it's still a bit clattery
at low revs, but it's better at higher revs now I've adjusted it.

Runs sweetly. Everything works.

Only slight niggle is I think the carb is suffering from Gunge
Suyndrome. I cleared a lot of crap out of the float bowl, and it doesn't
really tick over. If you wind out the throttle stop screw, then once the
idle drops below 2000rpm, it just cuts out. And if you have the throttle
WFO, it just hesitates around 7.5-8k revs, but picks up cleanly if you
ease the throttle shut a fraction.

Classic bunged up pilot jet passage, methinks, so some of that there
carb de-bunging fluid is needed.

Seat is utterly originasl and barring a tiny rip, perfect. All chrome is
remarkably good, considering its age. Paintwork is original and
extraordinarily good for the age.

I think I'll just MoT it and Nige it on Fleabay.