It physically looks like an NSR crank, but who knows. There are also differences between the early model NSR cranks and the later model ones. I dont even know for sure when they changed them, but somewhere in the MC18 era.

Also, the RS had a different style end than the NSR where the magneto pickup is. If it is an early model RS crank, you would have to use the RS total loss ignition system.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
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