The high compression ratio is very noticeable when starting! I've seen people starting 1.20 size O.S. engines using their finger and thumb to flick the spinner. You couldn't possibly do that on a similar size Moki.

To the best of my knowledge, Moki engines produce the best power to weight of any A/C engine - all done using straight methanol/castor fuel. I was fortunate enough to have spoken to Paul from Just Engines before I purchased mine (very sadly, he passed away about a month later). He advised that Model Technics Formula Irvine Sport 5 fuel could be safely used with the Moki 135 but reminded me that the 5% Nitro content would be tolerated, rather than enhance performance. The good thing is that this fuel is very easy to get hold of from just about any model shop.

Using straight fuel is a major bonus for obvious reasons. The main thing is that the oil content is 17-20%. If straight castor fuel mix cannot be obtained, 1/2 castor, 1/2 synthetic is acceptable. For normal sport applications, 1/4 castor 3/4 synthetic oil mixes are also permissible.

1.20 - 1.35 engines will typically reach 8000-9000rpms.

1.50 - 2.10 engines will typically reach 7500-8500rpms.

The crank on the Moki 1.20 and 1.35 are the same.

It's also worth noting that all but the twin Moki engines can be safely converted to Petrol.