seagull extra

My Feedback: (12)

I just ordered a 31cc Roybi from The Best Engines off of E-Bay. It was one of the reconditioned ones that have about an hour of run time on them. It is the twin ring type with the cylinder with no groves and I got it with the modified ie. opened up exhaust. They are claiming 7300RPM with a 20"x6" prop with this engine but from what Ihave been reading on these forms this RPM seems fairly high compared to what most owners are reporting. If anyone has one of these engines I would be interested in hearing what kind of performance you are getting.

JohnF

I have one of those too but I used a bigger carb. and Ch Ignition. I got up to 7900 rpm's with a 18x10 Master Airscrew. You will get different results depending on the tach. I plan to use a 18x10 Master Airscrew wood Schimitar prop and maybe try a 20x8. My plane is between 12-15 lbs but it hasn't been in the air yet. Good luck.

av8tor1977

My Feedback: (6)

What mods did you do to your Ryobi, if any?

Thanks,
AV8TOR

seagull extra

My Feedback: (12)

That sounds pretty good John. I am going to mount my mine on a CMP 77" Extra 330 for now. In the future I want to get a PT-19 for it but I have the Extra now and I don't have a engine for it so I'm going to give it a try. I know I'm going to be on the low end for power but if it turns numbers close to yours it should be okay. What carb did you use and do you know how much gain you got from it? I am going to run the engine stock first and then I may try bending the reed stop out a bit, but if there is a significant gain to be had from a larger carb I will do that as well. One othe question John. Did you get your engine from the best engines as well and are you using their high flow pitts muffler?

aero nut

if you use a 18X6W APC prop you could gain another 300 rpms my ryobi gives me 8200 rpms its a single ring and I run it on gas/glow.

captinjohn

I am seeing no advantage for using gasoline in with achohol fuel. Gas is dirty and cost more NOW. If you mix your own fuel it will be cheaper than the gas/glow mix. Capt,n

Ralphbf

My Feedback: (27)

The advantages are, you can run real carb. and tune it like a gas motor.
Straight Glow fuel ruins the diaphragm it the Walbro and Zama.

2 Quarts of gas and 1 quart of 10/10 glow fuel.
That’s $1.65 for a 1/2 gallon of fuel and $3.00 for the Quart of glow fuel.

I have gas /Glow engines that run better now than they did on gas.

Less weight, no raido interferance less to go wrong.

That's just to name a few.

seagull extra

My Feedback: (12)

Captinjohn what kind of rpms are you getting with your ryobi on straight achohol? I don't think I am going to go with the glow unless I really need to get rid of the extra lb. for the ign. What I am looking for is max performance on gas and from what I have read none of the guys on gas glow mix are matching the prop no's JohnF is reporting for his gas version.

av8tor1977

My Feedback: (6)

All my Gas/Glow engines run about 200 rpms faster than the same engine on straight gasoline, besides the weight advantage, and the smoother, lower idle, and easy starting.

The only exception seems to be my Ryobi, which doesn't seem to turn up quite as well as some others on either Gas/Glow or regular ignition. That's why I ask what mods have been done to the Ryobis that seem to run well.

AV8TOR

captinjohn

seagull extra: I have not run a Ryobi on strait alky. I like the 25cc homelite more. I will take a RPM reading when I get that engine back on my test stand. My friend has a tack. I tune them by ear! Capt,n

KI8FR

the advantages sound good and looks like fun to look in to.. When you say you can run a real carb.. what do you meen by real carb.. a glow carb or a walbro. Not sure on what you are saying..

And what is 10/10 glow fuel.. 10% nitro? [sm=confused.gif]

I have a hommie 25cc that is just looking to try somthing new...

What do you do about a glow plug. That is a big hole to put a small glow plug in to.. lol

I know that Im getting off the subject in this post but you all started talking about it 1st lol

Paul

captinjohn

You can get a glow plug adapter from Horizon that screws right in spark plug hole. Then screw in glow plug. Use a hot OS amx 4cycle plug. Capt,n

flyjoe540

seagull
I have the same engine with ch ignition, port and polish . I also opened up the exhaust to about 160 degrees duration .with the stock carb I get 7800 rpm on a 18x6 prop .

aero nut

I am using GAS/GLOW on all of my Ryobis; some Ryobis needed increasing of the exhaust porting to 150-155 degrees duration, opening the stop plate of the reed valve to 1/8", opening the ventury on the carb to 0.400", gutting out the stock muffler for free flow, use an O.S. "F" 4 stroke plug, an APC 18X6W prop and my fuel consists of 1 part 10nitro / 10% oil Glow Fuel mixed with 2 parts 91 Octane gasoline.
My oldest Ryobi which is a single ring engine is developing 8100-8200 rpms on these settings I was getting 7600 rpms on the original ignition system with gas alone. A friend is using GAS/GLOW with CH ignition and getting 8100 rpms with no mods other than the muffler. and another is getting 8300 rpms on his 2 ring newer engine.
So Gas/GLOW does gives a better performance than gasoline alone and it saves weight, no interference, inexpensive and it gives better fuel economy than Methanol/Oil mix.

homeboy61

Hello I have a Balsa nova 120 iam thinking about putting an 31cc ryobi in it will it work does any body know??????????

cwick1989

Yeah Im converting a ryobi for my huge spad... dont even know if the spad will fly yet but Im done with the engine except I cant figure out how I wanna mount it?

seagull extra

My Feedback: (12)

Well I'm still waiting for my engine that I ordered from the best engines on ebay but I bought a MTD weedwaker for $95 and have converted it. It was the twin ring model and it did not have the decompression slots in the cylinder. I gutted the stock muffler but the carb that came with the motor does not have adjustable needles so I am going to but a new carb before I run the motor as I do not want to damage my new motor on a lean setting. It looks like I'm getting a 12.5mm carb with coke and twin needels. I measured the stock base gasket and it is a thick .032" so if I make a new gasket out of thinner paper say .012" I can get a comp increase. I will post my prop no's once I have them. I'm hoping to match JohnF's prop no's of 7900rpm on a 18"x10" prop or I would be happy with anything over 7000rpm with a 20"x8" We'll see.

tstotts

got mine on a 4star 120 no mods on the engine and under propped. Flew it with an 18x10. flew well with no problems with the engine at all but was a lazy flyer (which isn't all bad) Flew scale didn't feel I had enough power for any real manuevers. going to do some mods on it before I take it out again. motor starts easily and sounds good w/good transition on stock motore and mag ignition.

seagull extra

My Feedback: (12)

I got my engine from the best engines and I did some bench running with it. I got 5800rpm with a Zinger 20'x8'. I know this is a heavy prop for this engine but I would like to run a 20''x8" if I can. It has a 8mm zama carb on it so I'm going to try and get a 11mm c arb for it and see what I get from that. If I can get 6500 on the zinger I will be happy with that. I also compared it to my MTD weedeater engine and was surprised to see that the transfer ports were quite a bit larger in the engine from the best engines and the piston is different as well.

av8tor1977

My Feedback: (6)

A 20 x 8 prop is just too much for a Ryobi. I only have a 20 x 10 on my 46cc twin and it turns it at 6700. I just read a review on a popular 45cc engine that turned similar rpms. You need to run an 18 x 8 max on a Ryobi. You are going to overheat it with such a large prop load.

AV8TOR

aero nut

use an 18X6W APC prop thats the best prop for the Ryobi, trust me I've tested all different types of props and this one is the best!!!

seagull extra

My Feedback: (12)

I tried my other motor from the 31cc weedwacker with the 20"x8" zinger prop and it had less power than my ryobi from the best engines. It is surprising how many differant versions of this motor exist. When I bought the MTD weedwacker and took it apart and found it had a two ring piston and no decompresion slots on the transfer ports I figered I had the best version of this motor but the cylinder on the motor from the best engines for sure has better transfer ports. As for the 5800rpm with the stock best engines Ryobi, I feel is not that bad considering that the Zinger is a very wide and large prop for a 20"x8" prop. It is just as thick of prop as my 22"x8" that I have for my DL-50. If I tried a master airscrew or topflite 20"x8" I'm sure I would pick up a few hundred rpm over the Zinger. I also decieded I'm not going to fool around with the stock ign. CH ign. has a new kit for the ryobi with the same auto advance module that my DL has for $119. This should make the engine smoother and a little more power maybe 200rpm. So between the larger carb and the ign. and a thinner brand of 20"x8" prop ie. master airscrew I feel rpm of near 7000 may be atainable with this engine. I will post my results when I get the new parts.

aero nut

try Hobby People's CDI ignition for the Thor 45 it's only $47.95 they work very good!!!!

aero nut

This is the link: http://www.hobbypeople.net/gallery/210246.asp

av8tor1977

My Feedback: (6)

Sorry to be negative, but if you ever get 7000 rpms out of any 20 x 8 prop with a Ryobi, I will be incredibly surprised, and you better make a bunch of them because everyone will want one. You could make a fortune!! 50cc power out of a cheapie mass produced 31cc? Go for it!!

Once again, sorry to be negative and sarcastic, but the goal is unrealistic. With a that large a prop, it would take almost double the power to get from 5800 to 7000 rpms. Even a 200 rpm increase with a 20" prop is a big power gain.

AV8TOR