I know some say the limmiting factor in hopping up the Ryobi is the reed valve. I did a search on the subject and turn up everything from jets to strawberry cake. What if anything can be done to modify the reed valve.

Thanks Peter

Simply bending the reed valve limiter out an extra 1/8 inch does wonders!

Just think...bigger opening...more fuel/air mix in....

Good luck!
CrazyHerb

Check out Jag Engines, they have good instructions for a complete conversion of a Ryobi 31cc engine.

Will

I guess I never thought about it, but some ideas come to mind.

Larger hole: One would need a reed with a wider head, or an oval opening so that it fits under the same reed. A tear drop shape reed would alow a larger opening.

A longer reed: I guess this would, in effect, be the same as what Crazy Herb says, but I gotta wonder.

One other thought: couldn't you put a small spacer between the limiter and the reed and get a little better result? This would also alow the reed to open more but would it cause other issues?

How about a thinner reed?

Tom

Spacer on the limiter would have same effect...as bending it out...

Which ryobi you running? Single or Twin ring ...that makes a HUGE difference...

Much more compression with the twin rings... easy to see, just pull the muffler off and look in the exhaust port at the cylinder.

I get awesome performance from mine just with high flow muffler from www.wackerengines.com.
Lower the back pressure and toss the stock muffler...

Here's a short video of my Ryobi pulling 18 lb Big Pink around...with smoke..on my web site..

Bambula 18x8 prop...
http://www.crazyherb.com/BigPink/bigpink.htm


CrazyHerb

Thanks for the reply's, gotta love RCU. I am converting two twin ring Ryobi's for a B25 I am building. Got one of them partialy converted last night. Got impatient and did not even take it to a machine shop to have the fly wheel turned. Found a old prop shaft adapter left everything stock, muffler etc. Put a 16 x 10 zinger (that I hate) and got 6700 rpms. Put a 17 x 8 apc and got 7200 rpms. Not too bad for the stock muffler and only 15 minutes on the motor (brand new) I hope to get another 300 - 400 rpms with a new muffler or gut this one. It will be interesting to see if removing most of the flwheel fins will attain more rpms.

Peter

Another option, if you like to experiment, is Fibre glass or carbon fibre reed valve. More flexible to open easier. Less chance of destroying the engine if it breaks. Still need the reed stop to prevent flutter. Done on racing carts.