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Reverse rotation
Is there a way to reverse the rotation of a ryobi engine? I want to use two of them on a twin, and I really would like counter rotating props. It seams that you could do it by changing the timing. Is it possible?
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RE: Reverse rotation
IF U USE A CDI ON THE NREVERSE ENGINE U ONLY NEED TO MOVE THE PICKUP OVER 60 DEGREES AND IT SHOULD RUN REVERSE WITH OUT A PROBLEM. A FLY WHEEL MAG MAYBE A PROBLEM. I NEVER TRIED THIS BUT I THINK IF YOU TURN MAGNETIC COIL OVER AND MOUNT IT 60 DEGREES ON THE OTHER SIDE IT MAY WORK TOO BUT IT WILL BE A PROBLEM TO MOUNT THE COIL OVER THERE. U SHOULD GO THE THE CDI I THIONK IT WOULD BE SO MUCH EASIER!
FARMER TED |
RE: Reverse rotation
The engine will run as well in one direction as well as the other as long as the ignition timing is changed
The key for the Ryobi flywheel is cast in place in the flywheel. People have been known to file off the key and put the flywheel where they want it. People have cut new keyways in the flywheel. The C-H ignition would be the easiest trick as was alreadt mentioned |
RE: Reverse rotation
A piston port is very easily reversed by changing the timing. The Ryobi has a reed valve that may cause problems when the air in the crankcase is moving the other way.
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RE: Reverse rotation
I NEVER LOOKED AT A RYOBI BECAUSE I DIDNT LIKE THE CARB AND MUFFLER POSITION BUT I WANT TO PUT A REED VALVE ON MY 1 BBL TORO. ID LIKE TO LOOK AT THEIR SYSTEM. WHICH RYOBI HAVE THE REED VALVES?
FARMER TED |
RE: Reverse rotation
ROTATING THE FLYWHEEL A LITTLE FOR A TIMING CHANGE WILL WORK BUT THERE IS SOME MAGIC GOIN ON IN THE COIL TO TRIGGER THE SPARK. SOME ENGINES HAVE 2 FLYWHEEL MAGNETS AND OTHERS HAVE 3 NOW 1 OF THESE TRIGGERS THE SPARK SO IF THE FLYWHEEL IS TURNING THE OTHER DIRECTION WILL THAT SCREW UP THE SPARK TRIGGER. THIS "NO POINT" SYSTEM FOR AN OLD FARMER IS NOT WELL UNDERSTOOD!!! IF U CAN SEE IT WORKIN ITS HARD TO GRASP!!! THE TORO HAS 10 DEGREES OF TIMING ADVANCE BUILT INTO IT SOMEHOW. MAGIC I THINK!
FARMER TED |
RE: Reverse rotation
Ted,
Good point. I forgot about the three magnet jobs. I don't have any myself. Enjoy, Jim |
RE: Reverse rotation
All the RYOBI 31 have a reed valve in the back plate.
ORIGINAL: TEDDYWILKK I NEVER LOOKED AT A RYOBI BECAUSE I DIDNT LIKE THE CARB AND MUFFLER POSITION BUT I WANT TO PUT A REED VALVE ON MY 1 BBL TORO. ID LIKE TO LOOK AT THEIR SYSTEM. WHICH RYOBI HAVE THE REED VALVES? FARMER TED |
RE: Reverse rotation
I don't think the incoming air cares which way the engine is turning;)
I reversed a stock G23 by turning the coil over and replacing the rotor on the crank...there is no need for the key, it's only there to position the rotor when the engine is assembled..I quit using keys on my conversions about 16 years ago..The keys on a tapered crank are too soft to drive the rotor if it comes loose anyway...O a straight shaft it's another story, but not many engines are like that..I know of at least one;) |
RE: Reverse rotation
A reed valve engine will run in reverse just as well as a piston ported engine. It's only the rotary valve intake two strokes that won't work this way, without changing/reworking the rotary valve and intake timing.
AV8TOR |
RE: Reverse rotation
DOES ANYONE HAVE ANY KNOWLEDGE OF HOW THE TORO 3 MAGNET IGNITION HAS 10 DEGREES OF ADVANCE BUILT INTO IT??
FARMER TED |
RE: Reverse rotation
Its not the incoming air, its the air in the crankcase. In normal rotation the reed opens and makes a small low pressure area that helps draw in the air. Reverse rotation canl cause the air mass in the crankcase to make a high pressure area under the reed and may cause spitback and reed flutter. Though the Ryoib reed is pertty stiff.
Only one way to know for sure , anybody got a tach and a Ryobi with a CH ingition.????? RC, G-23s don't count cause they are pistion port. |
RE: Reverse rotation
Terry,
Can you turn the rear cover over the other way putting the reed valve opening on the other side of the crankcase? I don't have my Ryobi in front of me but I remember a four bolt crankcase? Enjoy, Jim |
RE: Reverse rotation
Hi guys I'm not an expert but as the piston goes up in the cylinder. the reed opens and lets the gas charge into the crankcase then as the piston comes down it closes the reed and it forces the charge from the crankcase threw the intake port and into the cylinder above the piston which then the piston comes back up and fires. So in my opinion just put a cdi on the engine and change timing and you should be fine. I dont think the placement of the reed in anyway makes a difference. to change the coil and move it would be hard to do so just use a cdi. TKG I dont think it matters because there are 2 intake ports on a ryobi. I have a ryobi in my paws as I'm writing this and the 2 intake ports are on the side and the exhaust port is in the rear. I'm not sure but if it had 1 intake port then I think your theory would be true but in this case there is one on both sides. The standard plastic back cover has a slant inside to give room for the piston to come down so this back cover cannot be changed around on the back, would need to make a new one.
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RE: Reverse rotation
Not talking about the transferr ports but the reed intake port. If the reed was vertical or in a box then no problem but the Ryobi reed is flat on the back plastic plate.
ORIGINAL: Lureman Hi guys I'm not an expert but as the piston goes up in the cylinder. the reed opens and lets the gas charge into the crankcase then as the piston comes down it closes the reed and it forces the charge from the crankcase threw the intake port and into the cylinder above the piston which then the piston comes back up and fires. So in my opinion just put a cdi on the engine and change timing and you should be fine. I dont think the placement of the reed in anyway makes a difference. to change the coil and move it would be hard to do so just use a cdi. TKG I dont think it matters because there are 2 intake ports on a ryobi. I have a ryobi in my paws as I'm writing this and the 2 intake ports are on the side and the exhaust port is in the rear. I'm not sure but if it had 1 intake port then I think your theory would be true but in this case there is one on both sides. The standard plastic back cover has a slant inside to give room for the piston to come down so this back cover cannot be changed around on the back, would need to make a new one. |
RE: Reverse rotation
A reed valve has no way of telling which way the engine is rotating..it just doesnt care;)
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RE: Reverse rotation
In a Ryobi, the reed sets horizontal and opens on the right side of the engine at the point where the crank pin would have it's maximum speed going down. This assembly is very close to the crankpin/rod.
Enjoy, Jim |
RE: Reverse rotation
Any time the pressure is less than atmospheric in the crankcase, the reed opens and allows flow, and any time it is atmospheric or above, the reed closes. The charge is then compressed by the down moving piston until the transfer ports open, when it is forced into the area above the piston. The reed has no way of "knowing" whether the decrease in pressure that opened it came from the crankshaft moving one direction or the other. It only senses pressure and opens accordingly.
AV8TOR |
RE: Reverse rotation
I WANT TO PUT A REED BOX ON MY TORO SO I CAN GET A GREATER DURATION WITHOUT THE REVERSION. DOES ANYONE KNOW WHAT THE PORT TIMING IS ON THESE RYOBI'S WITH THE REEDS. MANUFATURER MUST HAVE THOUGHT THEY WERE NESSARY BUT THE OTHERS DONT. WHAT SECRET PORT STUFF ARE THEY DOING TO THESE ENGINES?
FARMER TED |
RE: Reverse rotation
It is difficult to install reed valves unless the engine is designed for them. On the high performance motorcycle engines, the reed box is angled to feed under the piston and use crankcase windage to boost the reed flow. Some engines also have ports feeding the transfers directly from the reed box. I would like to see a 50cc model engine designed like one of the 125cc Moto-Cross engines. It would produce about 15 HP. That should fly a brick.
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RE: Reverse rotation
ORIGINAL: TEDDYWILKK I WANT TO PUT A REED BOX ON MY TORO SO I CAN GET A GREATER DURATION WITHOUT THE REVERSION. DOES ANYONE KNOW WHAT THE PORT TIMING IS ON THESE RYOBI'S WITH THE REEDS. MANUFATURER MUST HAVE THOUGHT THEY WERE NESSARY BUT THE OTHERS DONT. WHAT SECRET PORT STUFF ARE THEY DOING TO THESE ENGINES? FARMER TED AV8TOR |
RE: Reverse rotation
agreed on above post, its just a pressure demand valve. the effect of proximity to the big end mentioned would be very complicated to predict, but ultimately in the state of tune of these engines I doubt it would be a measurable effect
obviously its in no danger of hitting it in any design with a reed stop, just in case anyone was thinking that;) Ive never seen a reed without a stop plate:D p.s...Av8.you got the pressures the wrong way round tho, .......gawd, im gonna get it now...next mistake I make[sm=spinnyeyes.gif] |
RE: Reverse rotation
You wanna see reeds with no stop plate, look in any 3w engine...Or a Homelite chainsaw reed in the BME engines, or D&B engines using Homelite reeds...There are more.....
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