Re: carb needles...........and the common prob of weak mixtures
Posted: Sun May 17, 2009 6:54 pm
Its surprising how little difference there is between one needle jet and the next available size and how much it effects the running of the engine with a dellorto Carburettor.....My flat slide Dellorto was running a K5 needle with a 135 main and bogged down a little at third to half throttle nothing massive but it could be felt as a slight stutter, above this it then starts to run right.....By changing the needle jet from a 265 to a 264 which is a difference of only 100th of a millimeter narrower, the engine was transformed.....Some people change needles for ones which are shorter or longer and have different tapers (shallower or steeper) and these can have a far greater effect on the engine than the mere 100th of a mm on mine....but such a small change can make a big difference....The pug is a good colour, as it was before, but the engine is smoother and more responsive.....a 100 mile run out today helped with the jetting choice....