What jet sizes while rebuilding ???

[topher1556]

Hi all!

I've got a 1980 GS1100E in stock form (airbox, exhaust, suspension, etc).

My question is, what sizes should I stick to for the jets (Pilot Jet, Main jet, Needle jet, and what position for the Jet needle)?

I've got a choice of either a 115 or a 107.5 main, a 45 and ?? for pilot. Just not sure which to use. Should I just match up what was currently in the carb? Oh, and I can't read the main size, so I know I need a suggestion there.

I'm going for best fuel economy here. That would mean an ideal to a slightly lean ratio if possible.

Oh, and I do want to say that this is the extra set I'm rebuilding to install in my bike so it's down as little as possible. I don't know what jet sizes are currently in the carbs that are on the bike right now.

Thanks in advance!!!

[KEITH KRAUSE]

I'm sure someone here has the factory jetting for your model. We've got a thread going that has detailed carb info for various models, but I don't know where it is here.
Just don't go any leaner than factory. These bikes come a little lean as it is straight from the factory. Trying to lean the bike out more will just make it run hotter and you may damage things that will cost a lot more than the money you try to save on gas.
Get your best mileage buy driving sensibly and keeping the bike in good tune. Run about 36 PSI in your tires and keep the chain operating smoothly. Lose weight if you're a little chunky.

[topher1556]

So I should just use the more rich choices of the stock carb rebuild kit?

[KEITH KRAUSE]

So I should just use the more rich choices of the stock carb rebuild kit?

No. I'd find out what the correct jets are and buy them new if you have to.
You want genuine Mikuni jets. The rebuild kit jets are often the wrong size and can be drilled inaccurately. Just my experience and many others.
I don't take chances with jets. They're not that expensive.