Since I had my old Ryobi 31cc apart to install a Frank Bowman ring, I decided to try it with the WT-499 Walbro carb from my G23 glow I had lying around.

Wow! Was I surprised. Even with the needles set very rich and the Bowman square ring not yet seated, the Ryobi was turning the 16x10 MA 8200rpm effortlessly on 15% nitro 18% oil. I momentarily pinched the fuel tubing and saw it blipped up in the high 8k range. I didn't dare run it steady near 9k, both while breaking in the new ring and with that darn stamped steel conrod. I have no doubt once it's broken in and I run it on a lot less (5%) oil, it will spin an 18x8 at the mid 8k rpm range. My guess is that it'll fly best with a 20in prop.

I can't wait to try this combination on the new twin-ring Ryobi 31cc I just bought. I hope Frank Bowman makes square rings for the new one, because I'm gonna get 'em! The twin rings look to be thinner than the single ring 31cc.

Okay, somebody is going to ask, so here it is:

bare engine w/ carb: just a little over 2lbs.
RTF as shown w/ B&B muffler and engine mount: 3lbs.

The overall cost is probably less than $125. Now why on earth would I want to pay twice that for a 160FX or a Moki?