Yeh, I know people who use the Scitsu and they do a good job. Need to be charged up which can be a pain with so many other things to do on race day. Personally I don't use a tacho at all on my race CB500, I just go by the engine revs and the feel of it. Not sure if I ever miss out on being in the absolute sweet spot of the range, but when I've ridden other race CB5's it's just been a distraction to me. In saying that, I do use it a on Monty's TZ250, (I don't really, I just have to say that so Monty believes me when I say I've not been over-revving it
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WeeJohnyB