Single carb on Rotax 670

[Andy]

Has anyone any experience on carb size and jetting for a Rotax 670? I plan on building one like Bob Wildmer's Rans S-9 Chaos. He in his Youtube vidio uses a SB 44mm Mikuni but doesn't give any tuning specs. In other notes I have seen on the net he uses a pair of SB 38mm with tuning specs. That setup is before he used the single carb. My opinion is he must of found tuning easier with the single. Thanx in advance, Andy.

[facthunter]

Use one carb per cylinder with 2 strokes is always a good rule. . THEN you know what each cylinder is getting. Gas flow in supposedly identical 2 stroke cylinders often varies a large amount and having a manifold going from one to two is just getting a problem you don't need to give yourself. Nev

[Student Pilot]

377, 447 and 503's all had single carb options

[facthunter]

Doesn't mean they are the answer. Any slight difference can throw the mixture out in a siamesed set up. The divider never divides evenly either.. Nev