Hitchcocks Forum

Hi everyone,
I bought back my 2001 500 Bullet a month or so ago. The previous owner has fitted a new carb' Amal Mk1 Concentric. When starting I get loads of black smoke and at tickover too. Opening the choke helps to reduce the smoke. I assume black smoke means too rich a mixture as the plug is very sooty.
Does anyone know the correct needle height and main jet size when used with the tea caddy air filter box?
Thanks,
Alan

Hi Alan,
Right before the experts get here, Basic advice (All IMHO ofcourse).........
...... Black Smoke Normally Means Oil..Ring's?"..
But Dark Grey at start up wet sumping."Dont worry" Read up on it, Running on Side stand can cause Grey smoke...Left standing for a week or Two "Wet sumping smoke & water condense = lots of grey.......
...Q: How Often Do you use it??... And (IMHO) You can blame a Carb for Lots of things But Not Thick black smoke???... "LASTLY" Check ya Plug whats it like & do's it start easy....

Cheers Craig

OK. Where to start? My dad fitted a free flow exhaust system to his Electra-X. He raised the needle on the CV carb as high as it would go. Then..... (wait for it).... put the original air filter back on! End result; Black smoke. Now, it really depends on the nature of the smoke you're getting. Run your finger around the inside of the end of the silencer. If the texture of the deposit is oily, the engine wants looking at. If the deposit is dry and sooty, then the carburation is suspect. The first step I'd take is to remove the tea-caddy air filter and run the engine again. If the problem clears up, then the air filter is the problem. If the black smoke persists, then the carb settings want looking at.

Sorry to be one of the aforementioned experts but black smoke is rich mixture and white smoke is burning oil. (although it can mean they've chosen a Pope)The Needle should be set on the middle groove as standard and adjusted from there.

Oh dear oh dear. Let's clear up some misconceptions here.

(1) Black smoke is a rich mixture. Your comment about the reduction when you open the choke demonstrates this.

(2) Blue smoke is burning oil, caused by any number of things....rigs, valves, guides etc.

(3) White smoke is condensation and usually occurs on a cold engine. A gallon of petrol will generate several pints of water. This evaporates when the engine is warm.

Ok which way do you consider opening the choke on an Amal

A gallon of petrol will generate exactly a gallon of water.

Yeah yeah blue smoke oil....

Thanks for all the helpful replies
The problem is due to the carb' having a 200 main jet. Seems that the jetting was set for a free flowing exhaust/silencer and a S&B air filter. Since I fitted a more restrictive silencer and will use a tea caddy type air filter plus not knowing which way the choke lever worked...(red faced!) no wonder it was belching out black smoke.
Hitchcocks are sending me a 180 jet.
regards,
Alan