79 GS750e running pig rich

[Northern Mike]

I picked up this 79 a few months ago, and after some poking around, nailed down most of my issues with it.
My last major issue is she's running pig rich. Runs strong and hard on new plugs for a bit, then as they get blackened, performance drops.
Bike is stock exhaust, stock airbox, new stock air filter.
It appears to be rich on all cylinders.
Other then hitting the air adjustment screw, anything else I should be looking at?

[Steve]

Well, the air adjustment screw will change the pilot mixture, but it won't do much for anything else.

If you haven't had the carbs apart, I would suggest a full refurb. Fortunately, it's not all that expensive, if you do the work yourself. If you don't want to do them, there are a few of us on the forum that will do them for you for a modest fee.

Several key things to check in the carbs (in no particular order):
- float level
- main jet size
- needle height
- pilot fuel screw setting
- pilot air screw setting

Outside the carbs:
- valve adjustment (won't make it run rich, but it is VERY necessary)
- spark plug heat range

.

[Northern Mike]

From what I can tell, the heat range is 8 stock on this bike. What about gapping? I haven't seen anything about plug gapping.

[Nessism]

The plug gap information is in the factory Suzuki service manual. You were provided a link to a free download via Basscliff's website in one of your older posts here.

I agree with Steve that you should go through the carbs. Full tear down, replace O-rings, verify the proper jets are installed, set the fuel screws properly, and lastly verify fuel level with the clear tube method. No shortcuts allowed.

[hannibal]

I couldn't find spark plug gap in the GS750 manual. Never looked for it on 550 or 1000 maunals. I searched and found some discussion on here, but not factory info. Can't remember what I set it to.

[Nessism]

I couldn't find spark plug gap in the GS750 manual. Never looked for it on 550 or 1000 maunals. I searched and found some discussion on here, but not factory info. Can't remember what I set it to.

The plug gap info is on page 76 of the FSM

[hannibal]

Thanks Ed.