MHR/SS tachometer

[spaniel1968]

Hi all, the tachometer on the post ‘76 900 SS special I have built is a nippon denso unit but it reads double the revs. I’ve looked at pictures of MHR bikes and it’s the correct unit for these era bikes from what I can see. The SS has the veglia/smiths units depending on wether uk or not models. I suspect I have the tacho for one of the single cylinder models as I believe these are 2:1 drive ratio. Can any tell me definitively how to identify the correct tacho for the MHR or is there a gearbox fitted to the back of the gauge on these particular bikes to give the correct ratio ? Or is it a redline position on the actual gauge that identifies it? They all appear to be about 8k start on the redline. I can see from photos that the engine is basically the same on a MHR as an SS and that the drive box on the front cylinder looks the same and there isn’t a cable gearbox on that either. I hope this all make sense as I’m quite baffled by it all.
Thanks
Dan

[BevHevSteve]

you need a 3.25:/1 drive for things to work. I have 1 for you.

https://store.bevelheaven.com/Engine-Re ... ah-S2-MHR/