Carb jets application

[jetta90]

Hello to all, picked up a 1984 GS 750 not too long ago. It used to have a 4 into 1 and individual air filters so the carb jets were changed to provide for a richer mixture.
The bike is back to stock exhaust and stock air filter at this time and I would think i need to go back to the stock jet settings.

What the carbs have now (jetted for the 4 into 1 exhaust and individual air filters)
Main jets - 120
Needle jet - Y7
Jet needle - 5D-10
Pilot - 40

What the carbs should have stock (from the factory)
Main jets - 117.5
Needle jet - Y6
Jet needle - 5D-12
Pilot - 37.5

Given that these bikes were jetted on the lean side from the factory, do you guys think that running the larger jet sizes above with the stock exhaust and air filter will make it run rich?
I know that on the main and pilot jet sizes the higher number = more fuel, does the same hold true for the needle jet and jet needle numbers?
The bike isn't in too bad shape but needs sorting out - specifically the carbs.
Valves are adjusted per spec. Carb floats are properly set.
Previous owner said bike had run rich when he had it running, which wasn't very often. If I let the bike idle for several minutes then pull the plugs, they come out very black. While idling it does smoke..............not blue as in oil, just smoke.
Ideas, suggestions and opinions please.
I just posted in the wanted section looking to find the original jets or I can trade if someone is looking to upgrade to a 4 into 1 and individual air filters.
What do you think??????

[chef1366]

Go back to the stock needle and jets and if the carbs are clean with good o-rings you should be good to go with a good sync. (If the motor has good compression ect....)
Do you have a local Suzuki dealer? I'd start there for the parts or Dennis Kirk online.

[txironhead]

Also, you can buy individual jets from Sudco.com, have no idea what the prices are though. They even sell Master Jet Kits with multiple sizes.

[jetta90]

Thanks for the responses so far, I may have to go that route if everything else fails. This is a tight budjet project so my funds are very limited.
With all the bikes out there that have been converted/updated from stock to a 4 into 1 header and pods I would like to believe that there stock carb parts sitting in someone's tool box doing nothing.

Check your tool boxes guys, there must be some hidden money there somewhere......................

More thoughts and ideas will be appreciated.