GS550 with Mikuni Dual Throat Carb, No Info

[Griffin]

I'm not surprised. The 16 valve '83-'86 GS550E/ES/L models were not made in great numbers, and had a tendency to wipe crankshafts if used for racing for extended periods of time. They had many parts unique to that bike only.

I had an '83 I used for racing in '86 and '87. They were very competitive with the GPZ550 and XJ550 Seca & FJ600. But then the the 600 Ninja came out in late '85, and the air cooled middleweights were swept off the track..

Your customer is best served by parting the bike out and finding a more common bike from the period that hasn't been put under the sawzall. The owners of the few left in good shape could use the parts.