I have a Tourer and have been looking for a rev counter ,i have posted about it on here before and the latest suggestion was use a
Garmin ECO Route HD Nuvi which i have looked at and found will cost about £150 +
I just had the bike MOTed and the guy there said he used a blue tooth OBD2 with a android tablet to check engine info on his race car.So after some time on ebay i have found that i can get setup for £20 as i have an android phone and 7in tablet .
Now this is not proven yet but just wanted to put it out there so others would know