Hi,
I have recently restored an Atlas from October 65. The bike is fitted with a pair of 389 Amal Monobloc carbs. As the engine has been rebult I am attempting to run it in however suffering very sooty black plugs (Bosche) after only a couple of miles. Bike starts fine but soon starts a misfire and pop on the right hand cylinder. Both plugs soot up quickly. I have replaced all the jets etc as per the manual and checked and rechecked the timing, changed plug leads and plugs. I do not know whether it's case of the carbs being warped with age or twin carbs not performing too well and gentle speeds necessary to run the engine in. Not too sure if it's significant but the bike has wide bore pipes fitted. From researching this site I understand it is possible to fit a 2 to 1 manifold and use one of the Amal carbs currently fitted? If I have this correct can anyone tell me where I might source such a part and what changes to jetting might be necessary. Any advice will be greatly appreciated. Paul.
hello your machine has bee…
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Another possibility is tha…
Another possibility is that the carb floats have expanded (new petrol to blame once more) and are catching on the float chamber covers.
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Thank you for your advice.…
Thank you for your advice. I have now ordered 2x floats, needles and settings and will give them a whirl. Many thanks Paul.
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hello your machine has been giving you black sooty plugs we its Not the Plugs or the Ignition is the carburettor that flooding in side the Carburetor there is lot of bikes doing the same thing with this new type of fuel (ron)95 what you need too do is lower the float level by taking out the float valve holder and filing the flat were the float valve fits you need to take a good 20 thou or more it finicky but this is the only way