this wil get you to american power sports I think but you can google the name and look for tachs digatron 30 or 40 series they are not cheap!
here is a tach and head temp gauge from American power sports GoKart racing
its not cheap but a very rugged gauge I have one on my racing kart. I haven't raced the kart in a couple of years so I might take it off the kart and put it on one of my bikes this tach will work on either 2 or 4 stroke engines it has a head temp sensor and a lot of features it will record your highest rpm and head temp etc. I know they cost more than the bike engine just wanted to let you all know what is out there. Turk brothers also sells them google racing karts you might be able to find this gauge for less money if you want to do some searching.