Yes there is no reason why not! A Temp gauge is as important for a air cooled engine as it is a water cooled one. So how do we do it.
1.Air temp gauge. If you look at the digital gauges you will find a digital temp gauge with a probe sensor. You drill a 5mm hole in the tin ware surrounding your engine, insert the tip of the probe and bond it in with epoxy.
2. Think outside the box. Fit an oil temperature sensor and gauge. The only difference between a oil temp and a water temp gauge is ........NONE! So use the sump plug to mount your sensor do the wiring and, jobs done!