I dug an already converted Ryobi out of the shop because I wanted to see if I could shorten it a bit. The result is a side mounted carb and a prop to firewall distance of 5". The change didn't affect the rpm and with the 1/2" pvc ell on the carb I picked up a couple of hundred rpm. Not shown is a ST 90 muffler with a 1/2" outlet and 360 degreese rotation. The flywheel and cut down coil weigh about 8oz. total. 16/10 prop spins 7440 rpm with an actual quiet muffler. Stock carb. Just wanted to see if it would work.

Nice job!
How did you do the induction? Still with reeds or rotary valve?

More details on the flywheel and coil.

Nice looking engine. Ryobi? What don't they make. I have a Ryobi 12V drill motor and just bought a 10" table saw. The drill has been great and the table saw (new) was only $75.00. What did your engine come out of?

Bill

The induction is the original reed valve. The carb mount is aluminum with a bore to match that of the backplate. The case is machined to match the o.d. of the new mount because the intake is recessed 1/2 of it's diameter into the case. There is a muffler extension availiable in 6" lengths that would require little work to accomplise the same thing and have the carb forward facing and still have the 5" length. Much less work.

The flywheel is covered a little more in an earlier thread, 6oz flywheel. It uses a neodyne 1/2" cube magnet and steel angles to duplicate the dimentions of the stock magnets. The coil is a cut down stock unit. I cut away as much of the potting material as I could and removed the iron core from the coil and machined the excess lenght plus a little extra that resulted from the shortened coil. The other thread shows a coil in the stock position using the same magnet and the original iron removed from the stock flywheel. I used the new coil location because of the round cylinder. If you get the magnet too close to the crankshaft (I believe) the magnetic field is scewed. I've tried several other locations. I use a 3/8" o.d. by 5/16 " i.d. prop ( like the OS multi cylinder engines) nut through the prop to secure the prop and the flywheel to the taper. With shims and a wide keyway, I can fine tune the advance from about 25 to 35 degreese. My timming light will pick up the spark so it times like a car. I have too much time on my hands and a bunch of doners. ProfG

This engine is out of a weed wacker ie. 31cc older version, single ring piston. California engine. The cylinder to case gasket has been removed and the head clearance is .025. The piston is chamfored and the case to bypass port seams have been smoothed and polished. Otherwise stock.

Thanks for the info. You indeed must have a lot of time, and you did make very good use of it.

Chapeaux!