Spedometer vs. Tachometer

[amontyg]

I have been having bunches of problems with my gauge cluster since purchasing my bike years ago. I own an 82gs550LZ and have just realized that it has the gear cluster for the X model on it rather than the Z. I realized this after visiting my local junk yard and testing out a speedometer which came off of a Z model. The X model seemed to always be off, way off. I'd be going about 80 down the highway and it would still read 55. The new gauge I bought reflects the accurate speed.

The question I have now is about the tach. It seems to me that where the spedometer must interpret RPM's to come up with the correct speed based on wheel size, the Tachometer simply displays the rotations of the cam shaft. This means that my X model tachometer should still be accurate, right? or do I need to purchase the correct tachometer as well?

[hampshirehog]

You are right. The tach gets its info from your exhaust camshaft so it will still be accurate.