GS750 Pilot Fuel Screw Technical Service Bulletin From Suzuki

[mattd1205]

Stumbled upon this TSB regarding the pilot circuit for 1977 GS750s. This may be of use to someone trying to figure out a starting point for their air and fuel mixture screws after a rebuild or whatever. I imagine the specs listed for the 45013 carbs would also work for the 45020 carbs found on the early model year 1978 GS750 (bikes built before January 1, 1978) as they have the same brass installed.

[billyhoyle]

LIFESAVER! I have a '77 with 27.5 pilots and 100 mains which doesn't match any of the configs seen in the compilation of carb settings so I was at a loss as to where to set my fuel pilot screws. I started at 3/4 out, still idling rich but not bad after some fiddling with the a/f screws. Backed 2 cylinders off to 1/2 out on the fuel pilots and it got slightly better but now I'm going to try 3/8 out as suggested here and see what happens. Flipping massive pilot jet in these old carbs.

Side note, does anyone know if these #15 pilot jets will fit the VM26 carbs? They look identical to my 27.5s...or does anyone know of a good source of #15 pilot jets in Canada? I'm at a bit of altitude (~1000m) so I'm pretty sure I don't need the extra fuel flow of the 27.5 fuel pilot...

[steve murdoch]

I didn't look through their catalogue but in Canada i would have a look at Sirius for jets.

https://www.siriusconinc.com/

[Big Block]

Thanks for posting. I have my 77 close but it just isn't right yet. I'll fiddle with it again. Hmm, according to my notes I am .25 turns out on the fuel screws too much. You would think the air mixture screw could compensate for that. Maybe i'll crank them in anyway.