Jet recommendation for '83 GS550L Carbs?

[Snoburd]

Hi, I'm new to the forum and am looking for some advice. I am building a Cafe Racer from an '83 GS550L model. As part of the modification, I cut off, narrowed, lengthened and raised the tail section. All this was easy since this bike has a mono-shock with a steel frame. The modifications required that I S-can the air box, it was in the way.
I replaced the air box with two 4" Uni Foam filters. This bike has two Mikuni BSW30SS dual throat carbs. I think that '83 was the only year that Suzuki used these carbs then went back to four carbs (not a good sign).
The exhaust is stock. Any suggestions for sizing jets?

Thanks

[JEEPRUSTY]

The siamese carbs were used from 83-86.
They are are the GS400 in the japanese home market as well.

They allow a bike to narrow at the carb rack or so the literature says.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Snoburd,

I don't have any specifics for you, just some general guidelines. There are carb and jetting tips on my little website. I think you'll want to start by going up 3 sizes on the mains and probably shim the needles if you need to richen up the midrange. You'll probably have to turn out the idle mixture screws too, about 1/2 to 1 whole turn. In order to fine tune your carbs you'll probably have to do "plug chops" and read the plugs. You do not want to run lean and burn up your motor. You might want to check with Dynojet and see if they have a jet kit for your bike. That will take out a lot of the guesswork, but you'll still need to read the plugs to make sure all of the carb circuits are tuned properly.

Anyway, let me dump a TON if information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

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