im just starting to break this engine in.

im getting:

MAS 16x8 9000RPM




im curious what others are getting with their ryobi's

71~7100 rpm with the same prop. Want'a trade?

9000rpm is too fast for the Ryobi. It is designed for and is timed to run at 7000rpm. Try an 18 X 8 or an APC 16 X 10. I think you'll like it better.

Getting 7800 with M.A. classic 16x10, and 7500 with M.A. classic 18x6. I raised my comp. ratio by removing the jug to block gasket and just using rtv.This brougth the jug 27 thousanths closer for a substantial comp. increase essentially for free.It was good for about 2 to 3 hundred revs on a 18x10-14 zinger .This was the only large scale prop I had at the time .If anyone else tries it let me know results.Thanks

i just built a dual stack muffler and noticed a big jump in RPM. i have not had a chance to compare them with the tach, but can tell from listening that it is much improved.
ill post a picture of the muffler soon.

I removed my base gasket and my Ryobi detonated terrible! I had to replace the gasket for any decent top end power. Also I have a Bennett muffler. A little loud but good power. Sorry, I have forgot my rpm #s. Very reliable conversion. I have 2 more to build. I am thinking about a ryobi conversion to power my self powered reel mower.

Jimmy

Jimmy did you try hi octane gas if so the only thing I can think of is your ryobi must be a later model than mine & perhaps yours already had a higher comp. ratio, mine suffered no ill effects.

ZB50
Can you still use a standard electric starter with the higher compression?

It started very easily,,, even with the "quick start"!. It just made a hell of a knock and low power when at full throttle. I took it to the field and barely got it off the ground and an old guy there said that it was for sure detonating...... Anyway, the gasket back on the cyl took care of the problem. Now it runs like a watch!!!!


Jimmy

I forgot to mention I use a Sullivan Hi tork starter. I might add, it was my original starter first used in 1972!!!!!!


Jimmy

Jimmy I don't know what the difference between your's & my motor but mine easily starts with a tower hobbies heavy duty & a 12 v. motorcycle battery.I guess a guy could run a comp. check wih a auto or motorcycle type guage & it would for sure tell if yours is higher comp. trhan mine,also I guess you don't run rich and would'nt have corbon buildup as you seem very knowledeable.Anyway I would advise anyone trying it to listen for this potential problem as I've done this twice ande had sucess both times.As a matter of fact Jag engines owner has even cut down a few cylinders and maxed out the comp. by using the folded solder method and he told me he has had good success.Anyway try it at your own risk.

Buckeyes 97:
Is your Ryobi a single or double ring version? It has been 6 months since your post, how about an update on Tach readings? and any tips you may have?

7560 on a 16x10 APC. 1 ring vesion.Im' totally pleased with performance except for I cannot seem to obtain a reliable idle. My 4 Star 120 with smoke and full fuel still weighs under 15 lbs. and flies great, about everyone that sees it fly is impressed.I modified a Jag engines muff. to put in preheat coils will explain how if anyones interested.

16-8 APC 7650 tonite starting to wean it of regular oil. On stand it will idle down to 2140+/- and run smooth. I have not run it on the plane yet, hope it will sit still at that rpm. (US120)
I did remove the butterfly and soder the small vent hole closed, could not get it to die with throttle closed before, shuts down now.

Not familar with the jag muffler but would be interested in the preheat coils project esp. if you have some pics

I don't have any pics but i probably can describe it. The Jag muff is a two piece unit that is circular with the out tubes rotatable 360 deg. Make two holes one on each side of the main body slightly larger yhan 1/8 in. next coil two tubes of 1/8 brass or stainless slightly larger diameter than the ID. of the muff. I wound one clockwise and the other counterclocwise with about 1 in. left strait to put through the holes you drilled.P.S. you may have to slightly angle your holes to be able to guide the strait ends through to the outside .Now use Hi temp. RTV. on the inside around the holes . If you made your coils a little large they should spring outward holding them in place, lastly squeeze the ends a little to make the oil spray when coming out and direct the ends towards the exhaust a little. Now bolt the back on and your finished use a tee to feed both sides just like the slimline mufflers do.