Ariel Owners Motorcycle Club

Hi All, I have a 1929 SV Ariel the carb is 1" bore, the numbers off of carb are AU 3701 and 6/112, main jet is 150 and needle is either 2 or 5 cannot make it out and is on the second slot from the top, I have removed carb bolted on to a upright board and filled with fuel through filler pipe till the float chamber stops fuel coming through also I have ground in the fuel cut off with fine paste so it is a good fit , looking in the main bore with the slide out the main jet holder is about 1/8" below the bore is that about right, the fuel level is about right with the top of the main jet holder, are the jets about right, the plugs a bit dark but I have only gone on very short trips to the top of hills both ways from the house till I am sure about the bike running ok. Any info would be welcome its a steep learning curve but am slowly getting different jobs sorted apart from the carb at the moment, Regards Clive.

The fuel level should be at the top of the mixing chamber nut 6/062 or 6/033. Your should have the 6/062, which is the deep one as shown in all parts diagrams, Ariel never used the shallow version 6/033 recognisable by the negligible gap between the hex on the bottom and the plain round part.

Settings are MJ 150, slide 5, needle 2nd groove from top, .106 NJ and 15 degree float chamber. The main jet screws into the needle jet 4/061, the top of which is usually slightly above the floor of the mixing chamber. Don't concern yourself with the main jet unless it is dramatically too small as it has no effect until 3/4 plus throttle opening. Check for play between the slide and the body, you would think that excess play would cause it to run weak but it does the opposite. If there is a lot of play have the body and slide repaired, there are several people doing it by various methods.

Hi Roger,
Thanks very much for the info., I will check all your measurements and take it from there is will not show its true running till I give it a good run out thanks again Clive.