I’m over in Australia, and recently imported a Motocompo folding scooter from Japan, as I’ve always wanted one to go with my Honda City Turbo II. She’s in pretty good shape, though required a complete clean of the Keihin carb before she would work again. I’ve had her running up and down my street at a whopping speed of 38km/h (~23mph), haha. (This is on a tiny 8” tyre mind you!).
Anyhow, I believe the engine is very much the same as the NC50 / Hobbit, so have been looking into doing a 70cc upgrade (along with carb, pipe etc). There seems to be a lot of good reviews on kits like the DR, Malossi, Athena etc, though the DR and Malossi seem to be more ‘plug and play’ than the Athena. I am stumped on the head options though, in that they all seem to have very small cooling fins. The Malossi head, Athena head and Polini head all show the same thing, - tiny fins. Why do they have that, and should I be concerned about overheating because of using a head with a much smaller surface area? I’ve read of people re-drilling a Puch head just to have the benefit of additional cooling area. I just don’t understand why the likes of Athena and Polini make such smaller 70cc heads, but that’s why I’m asking the experts here!
Also, what is the function of the grooved ring on these heads? (as per picture shown). Is it anything to do with the decompression valve? My motocompo doesn't have a decompression valve, so I am trying to steer clear of any heads which are suited for those.
Thanks so much for helping!