S2 Tachometer reads 15% high after conversion

[Robin_O_Connor]

@bobgthomas

Robin, no I don’t think the factory is confused, but I do think you are. Again, the OP is NOT talking about road speed, but you are.

He is only talking about engine speed

Which relates directly back to RPM!
So sorry I am not confused, the OP has a problem with his RPM (tachometer) differing from what he is seeing against his timing light (with RPM readout)

[Andy.Preston]

Wow guys I thought I asked a very simple question, which just goes to show how wrong I was; I think there are too many well educated informed members and engineers on this site which always keeps things interesting.

Thanks for all your responses but there does not appear to be an easy way to adjust the tach. I’ll just send it out to a reputable repair shop and have them correct the over-reading.

Thanks for your interest,

Andy

[Michael_Frank]

So I’m late as usual. You can calibrate the tach yourself if you have an accurate shop tach. On the back of the case, there will be a rubber plug, or maybe a bit of tape covering a hole. Remove it and insert a small screwdriver. Then just adjust until the dash tach matches the shop tach. If you do this at idle speed, it should be accurate all the way up the rev range. If you find the reading becomes eratic, you can replace the notorious capacitor with a higher value. Sorry for the late reply.