Hey ive done it again. yet another peeved of customer lol.

Buddy im sorry but if i had a dollar for ever hour ive waisted reading stuff on the internet on this engine then i would be rich. I havent seen to awfull much info on this subject really. maybee there has been some good posts but i sure cant find them. the original intent of this thread was to take all the fragmented info on this subject and try and put it all together into one good post on the subject. My hope was that there would be a good pool of people presenting information with test data to back it all up. I really wanted to hear from those that are new to this hop up and those that have done it and had great sucsess. to date the largest contributers of this thread are those that are working along with me to make this thing perform. I havent heard anything from those that have all the mods that we havent even scratched the surface on or seen any relevent information on this submitted.

Ya know the more i think about this statement the more it iritates me. You make the asumption that I or anyone else here has not looked and looked and looked for this information.

Im gona make an asumption of my own. the fact that you are not willing to contribute this information that we cannnot find leads me to belive that you really do not have this information or have ever seen it to begin with. no body asked you to babysit but only asked you to make some usefull contribution. you say its there. I say i cannot find it. you say im not willing to read. I say your full of it and put up or shut up.

Again i dont expect you to look up any data on this cause i really dont think you have any data on this.

Oh god there gona kick me off here.

I'm glad you said it, because I was thinking it.

ya know, it would be real handy if the people who push searching and know of an actual thread, would give the name/search criteria. or hell even a link to the tread they need. I have came across lots of threads that were realatively unrelated to my searches.
Combat, you have my support in what your doing. There is too much fragmented info, and some info that is outright BS! We need more threads like this, that show what works and what doesnt.
Keep up the good work.

captinjohn.... Your custom reed valve looks very interesting but what effect does it have in performance of the Ryobi motor when compared to the stock reed valve?? Is there an improvement?? Do you have some data?

It's not enough to theorize configuration changes that may improve performance and declare them as valid. One has to demonstrate that the theory works in practice. You must MEASURE the performance with the two configurations to see what the effect is. Obviously if there is no improvement in performance, or some other tangible operational benefit, then it's not worth the effort to modify the stock set up.

diceco

PS. After writing the note above I discovered that the photos of the reed valve set up you included in your post #366 are not yours. They are pereivers. Furthermore pereivers, in his performance table on his referenced web page, does not show a direct comparison, using the same prop, of the stock reed and his modified reed valve.

Keep searching...and thow shall find!!! Capt,n

Sorry cap.... I'm not interested in playing your childish games....

diceco

Say andrew66. I would jump at the chance to get a stock magnito system that I could hand start. Would you be willing to give us the particulars of your motor such as what vintage is it and what weedie it originally came from and maybe some numbers off the coil and flywheel unit you have. If anyone else is able to hand start their stock Ryobi please speak up with the same info.

Maybe too someone has already figured this out. Please speak up if so.

Thanks, diceco

I WAS THINKING THAT ALSO!!!!!!!!!!! Capt,n

My ryobi is a bit of a heinz 57. The case is an old style short shaft (the one where the mounting shroud bolts on) not really sure what trimmer it came off of. The jug is off of a newer short shaft yardmachines trimmer (maybe the 1500 series if I remember correctly) and the mag is off the engine that i got the case from. The only numbers that i can read are 2 53 on the front side. There is a brand name on it as well, but its so worn that i cant really read it. My ryobi engine is kinda buggered right now. The last time i ran it, my phone rang, and I walked away to answer, and I noticed that the engine was considerably louder. Apparently the muffler bolts backed out, and ruined the threads in the jug. I tried using a bigger tap and drill to maybe salvage it, but the holes arent round anymore, and if i use any bigger than 1/4" It wont work. So if you would like my mag and flywheel, you can have it. Maybe a trade for some other parts? PM me if your interested.
I also noticed that in order to hand start my ryobi, It had to have a healthy prime before it would even consider starting. I also have to give it a pretty strong flip to get it to go.
I will be going up north for the weekend, so when i get back, I will try and get pics up

I don't have a Ryobi as of yet but my Poulan convert, didnt seem to have a spark, so I checked the plug gap and it was about 30 thou. I reset it to 20 and then I set my coil gap to 10 to 12 thou. Then I got a spark when fliping by hand and after changing brand of plug I can almost hand start. It will pop but not quite take off. I only have to bump it with a starter.

You probably already know this, but it worked for me.

So has anyone come up with the final definitive Ryobi??

As far as I'm concerned I've done all I can with mine.

1) It's a late model with the integral fan shroud
2) Bifurcated transfer ports with substantial radiusing and smoothing of the webs at the entrance to the ports (see posts 134 and 145). Unfortunately I don't have a measurement of the effect of the T port mods.
3) Two ring piston and "I" beam style rod. This only means that the stock rings on the later Ryobi seal just fine and the rod may be stronger than the older Ryobis.
4) Contoured reed valve to precisely match seat.
5) Bent reed clamp so the reed clamps at just the base of reed as opposed to stock which clamps well down the reed toward the port opening. This gives less reed force required to open.
6) Enlarged cylinder exhaust port to give increase port area and 160 deg timing.
7) Stock muffler with 5/8" ID outlet pipe replacing the 1/2" ID stock internal pipe.
8) 12.7 mm venturi carb.

It is my belief that the major performance producing mods are, at least for the late model motors, in order of importance:

1) Larger exhaust pipe on stock muffler or after market exhaust.
2) Larger carburetor
3) Exhaust porting

It is my intention to eventually get a performance derivative on the transfer port entrance mods to see if it's worth doing. It's a fairly time consuming process.

I would also like to work up, from stock, one of the older Ryobis. I'm collecting parts now but am still lacking a good cylinder with the single runner transfer ports. I also don't have a stock muffler anymore as I modified the extra one I had it to see if opening it way up would make any improvements.

My Ryobi is developing 15 lbs. of thurst at sea level static conditions with an 18 x 8W APC prop.

Most of these mods are explained in detail somewhere in this thread.

Also see post 332 where combatpilot is getting 14.2 lbs thrust with an older style Ryobi AND a different prop. From reading some of the discussion information available I get the notion that APC props are the most efficient ones out there so it's possible that combat's motor may give more thrust with the APC prop. For the older Ryobis, as combatpilot and others stress, you must first be sure the piston ring is sealing well for good performance.

diceco

I have got to say i think this thread is gona be a work in progress for a long time to come. there is more that can be tried I just havent had the time to do it. I have gotten side tracked on work and some other projects that are screaming for attention.

I agree with diceco on much of what he said in the last post. I do think a apc prop will most likelly produce more thrust. I think there is a bit more reasearch and development. that goes into the apc props than the dynathrust that im using.

As far as a difinitive ryobi im gona say no. theres always more to learn or the next better idea and i dont think we have tried everything yet. again i think this is gona be a work in progress for a long time to come.

Apperently we havent even scratched the surface on this subject but for as hard as i scratch i just cant get below the surface lol. sorry couldnt resist.

Flathead 4 has returned from 10 days in the Southwest, mostly Arizona. The RYOBI is screamming for attention, but so is the yard. Give me a couple days and I will be back testing some new ideas and additional information. Flathead

Don't you just hate [:'(]responsibility.

yea i know resonsibility suks

I ran my stock single ring Ryobi 31cc today, and that thing seems to pull pretty hard with an APC 18x6. I didn't get my tach out and see what it was doing, but perhaps tommorrow I will get some readings. I did take a short video of it running and posted it on you tube. Not a real good video because I just thought to take the video as my tank was nearing empty, but thought I would post it anyhow. Neighbor came over and watched it run for a bit, and then came back and gave me another Ryobi weedeater he had sitting in his garage. He said it pulled to hard for him and he bought a newer easier pulling weedeater. The one he gave me is the older 28cc engine so I am hoping that maybe it has lots of compression due to an extra ring, but I will have to dig into it to see.
http://www.youtube.com/watch?v=XxFcxyWr7Dc

Is it just me or is the plane vibrating like crazy when you come up to full power?

I really didn't notice it vibrating that bad, or at least not what I would call excessive for a gasser. I am certain that when the wings are mounted it will also help dampen vibration to some extent. I should probably double check the prop balance as well, but the only real thing I noticed in the video is that there is a wheel pant that I still need to fix that is loose that moves excessive when I reved it up. The vibration back at the tail feathers looks pretty much the same as my Zenoah G38 that I had on a Giant Super Sportster. Actually I really didn't notice it being any worse than running a big Saito 4 stroke, but after watching the video again..it does look worse in the video than it actually was.

Last week I was given an animal that I have not seen before. I was labeled a Craftsman 32cc weedeater. Looked just like a Ryobi. I took it apart yesterday and this is what I found.

I was definitely a Ryobi. Had the same back plate and looked just like a long shaft ryobi with the cast on mounting on the crank case. However, things started to look different when I took the muffler off. The head did not have the cast bridge in the middle of the exhaust port. I could also see that the piston had two very thin rings on it. When I pulled the head off, I found that the crank looked just like a normal Ryobi crank with the riveted together counterweights. Also, the connecting rod was of the riveted together variety. However, the head had two transfer runners per side. The crankcase had a wider mouth to the transfer ports. The piston had two very thin pinned rings and the pins looked to be recessed rather than stick out all the way to the edge like on one of the single ring Ryobis. The piston also had some machined out flat spots on the side facing the transfer ports. Looks like they may be boost ports. And finally, the head had no exhaust slits in it. This engine seemed to have more compression than any I had looked at in the past as well. The difference was very noticable.

This looks like it might be a more hopped up engine than the garden variety Ryobi. Has anyone else seen one of these?


Jim

I have a Ryobi here that looks brand new on the inside-still very shiny and clean. Anyway, it is the version that has a "slot" on either side of the cylinder up near the top of the head-I couldn't gather a good answer yet...is this type worth converting or is all the power robbed from the "slots"? Thanks!

I'm sorry to say that your slotted cylinder is not a good cadidate for an R/C motor. See posts 120 and 145 of this thread.

diceco

My brother has a Ryobi with the slots. It has a slightly larger than stock carb, and the original muffler gutted and provided with a larger outlet, and electronic ignition. No other mods. It turns an 18 x 6 prop at a little over 7500 rpms and flies his 14 lb. +/- 80" span Ryan's Rebel quite well.

AV8TOR

It sounds like this is the late model Ryobi. It IS a good candidate for an R/C motor. It already has good compression, The piston has better support with the center web between the transfer ports. The rod has an I-beam shape which theoretically should be stronger than the older style. The exhaust port looks like it would flow better (although it could be opened up, see post 284). It can be considerably improved from stock configuration but it's probably the best one to start with. This is the motor that I worked up and is described in my posts on this thread.

I believe too that the long shaft motor is better for R/C conversion than the short shaft Ryobi, especially if you want to convert it to electronic ignition. When converting to electronic ignition the prop adapter is keyed to the crankshaft as opposed to just screwed on tight which is the way it works with the short shaft version. It's also a piece of cake to affix the spinner on the end of the long crankshaft.

diceco