Topic: Carb Guru needed for help with TX750

[RoytheBoy]

I own a 1973 Yamaha TX750 Twin (as well as a CB750 K7) which has been converted at some point in its life to a single carb, still has standard #45 Pilot jet, #130 Main, Z6 nozzle, 4N8 needle with clip on lowest (nearest needle end) point.........

Carbs are not my strong point.........so my question, as this is a single carb it obviously now needs to draw in enough fuel/air mixture, are there any Guru's out there could tell me if these sizes are correct/good starting point? Assume a #140 jet is larger? would that be the way to go?  Trial & error?

any help much appreciated
Roy

[Scott S]

 Hey Roy, and welcome. I'm sure there are some carb gurus that will chime in, but another good source for the Yamaha twins is http://www.xs650.com/forums/ . There main focus is the 650 (and there's a sister site for the 400), but there will DEFINITELY be someone there that knows the 750.

[Bankerdanny]

Here is some useful info on jetting: http://www.jetsrus.com/FAQs/FAQ_jet_kit.htm

Your spark plugs are a good source of information on the air fuel mixture. The color of the deposits will signal if the mixture is lean (too little fuel) or rich (too much fuel). The article at the link has a section about reading plugs.

[SOHC4 Cafe Racer Fan]

I had a 1974 TX750 with the different head, but didn't get to carb tuning (it was a flip bike).  Watch out for the oil starvation issues on the 1973 model.

[RoytheBoy]

Cheers guys, looks like a certain amount of trial & error.........Roy