Originally Posted by latemodel13
Hi, Can someone tell me the difference between the R-01 and the R-03 .21 engines. Are they close in H.P. and rpm.
The two engines are identical except for the sleeve material. The R-01 is an aluminum sleeve (AAC) just like the old 421P from Novarossi. For some reason or another(longevity maybe) they discontinued the R-01. The R-02 is the 7 port version. Get an R-03 if you have a choice.
*I just checked the website and it says differently. BUT, going on my past experience and watching the JP motors that others around me have used I stand by my statement.