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Ryobi differences... Comments??

Old 01-13-2009, 07:54 PM
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buck1856
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Default RE: Ryobi differences... Comments??

DANG,Av8tor your always one foot in front of me.If you decide not to take it[wich i know ya will].Send me a pm so i can.
Just like those BME twin cases.
But i did finally get onea year later.
Pulled my last new 2 ring short shaft ryobi apart.It has the new style reed.It has the rod that has the 90 degree bend at the outside edge,55mm case.
I just sent a 10 lb package to switzerland that cost $50.00 so your little reed block from PE shouldnt be much at all.
Old 02-06-2009, 07:55 PM
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Flathead
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Default RE: Ryobi differences... Comments??

In reference to your short shaft engine with a smaller crankcase and diffrent reed valve set-up. I have been doing tests on several different setups, and this particular set-up is unique, but was manufactured and sold under several different names. If you want to part with this crankshaft and backplate, let me know and I will try and work out a trade. I have a lot of different "STUFF" to include Poulan, Homelite, Ryobi, McCollough, and a lots more of different names. Flathead
Old 02-07-2009, 05:04 AM
  #28  
av8tor1977
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Default RE: Ryobi differences... Comments??

Hey, send me a pm with an offer. I have all the parts in good condition.... I would be interested in a Homelite 33cc from a chainsaw if you happen to have one...

AV8TOR
Old 02-07-2009, 12:14 PM
  #29  
bat.guy
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Default RE: Ryobi differences... Comments??

Ya otta make a few of those[sm=tongue_smile.gif] and list um in RCU classified. I've been looking for Ryobi reed valve solution for years and evidently Im not the only one.
Old 02-07-2009, 02:09 PM
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Flathead
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Default RE: Ryobi differences... Comments??

Hey Av8tor, give me a shout at [email protected]. Several things to run by you including trade. FLATHEAD
Old 02-09-2009, 09:09 AM
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hammerx5
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Default RE: Ryobi differences... Comments??

Out of 6 or 8 ryobi engines i have one that has 2 thin compression rings insted of the 1 thicker ring. I have not used one of Frank's rings but the twin ring, no slitt cylinder, large crank case and short shaft has 3 times the compression as the single ring in the same set up. Is this a coman piston are a rare find? It is the only one I have ever seen.


I will try to let you know about performance when I get that info.
PS It came out of a Lawn boy trimer. I also got a small crank case engine out of a Lawn Boy.
Old 02-15-2009, 09:29 AM
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combatpilot
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Default RE: Ryobi differences... Comments??

Av8tor77. It is really interesting that you have had such a large gain in power output indicated by your rpm gains. I am fussing with a ryobi I have converted a couple of years ago. Its been a while but i think it is a long shaft with 2 rings. I have the good backplate that has the reed valve flush mounted. The best I can do on a stock set up with a paragon muffler and stock ignition is 6450 rpm. this is on a 18-8 prop. I am wondering where yours would be with a 18-8 prop?

I would also like to know
1. what brand of electronic ignition are you using? Where did you get it as I also want to set mine up with the electronic. Hobby kingdom has a replacement set up for their engine that can be had complete with shipping for under 40$

2. How did you figure removing the gasket droped it .035? My case has a couple of small ridges cast into the case where the gasket goes to aid in gasket sealing. Did you also remove these ridges?

3. When you drop the cylinder gasket I understand it ups compression which is good. compression = power. However how does this change the port timing and how does that affect power output? I noticed you said you changed port timing to i tink it was 152 degrees. How did you accomplish this and could you show pictures of this mod? why did you use 152 degrees. How was this number derived to be a good point for port timing?

4.Did you do any modifications to the reed valve plate other than setting the reed valve stop at 1/8 inch. I think i read somwhere you decreased the lower end chamber volume. Is this true and how did you do this if so. again pics please lol.

5.you say you used an 11mm card. I am asuming the 11mm refers to the venturi size? I have a 12.8mm carb on the way. Was this gain in increase also due to a larger carburator? Was the original rpm number with the small stock carburator? Do you have the number off of the carb and where did you get it?

6. What did you do to the flywheel for the elecrtronic ignition and how did it affect balanceof the engine?

I have seen somwhere that there are two different timings of these engines. the one with standard timing you will see if you put the crank keyway straigt up twords the cylinder the crank rod journal will be straight up also. The one that is considered higher performance has a bit of advance in it. On this model if you put the keyway straight up the rod journal will be more to the left side when viewed from the top with the back of the engine to you. It is possible that your vibration problem may be due to this if you did not use the original flywheel that came with the timing of the engine. If you use an aftermarket electronic ignition with the hall effect trigger switch then this stock timming is unimportant as you canset it anywhere you want anyhow.

Thanks so much for all this info.
Old 02-15-2009, 12:35 PM
  #33  
av8tor1977
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Default RE: Ryobi differences... Comments??

Yeah, I was very pleased, and somewhat surprised how this Ryobi turned out. It runs very well and has good power. My brother has a Ryobi that is basically stock except for electronic ignition, a slightly larger carb and a gutted muffler. His engine has the slits in the cylinder. It turns an 18 x 6 prop at about 7600 rpms. My modified Ryobi turns the same prop at 8500.

Answers:

1. I am using CH ignition. Electronic ignition frees up some power, as the mag uses some power to generate electricity, and also just to turn the flywheel with its fins. Being able to optimize the ignition timing also adds power. Mine is set at 28 degrees BTDC.

2. I miked the compressed gasket, and it measured .035", so leaving it out lowered the cylinder that much. I did not remove the ridges on the gasket surface. I used Yamabond sealer in place of the gasket.

3. Yes, lowering the cylinder increases the compression, but it also decreases the exhaust and transfer port timing. Some of the Ryobi's have a very low exhaust port timing anyway, (around 120). 150 degree exhaust timing is a good general number for an engine to run up to about 8000 rpms. You can go to 160 or 165 degrees for higher rpm use. Much more than that and you are into the range where a tuned pipe would be needed to effectively utilize the high port timing. You raise the port roof to raise the timing, but do so in small amounts and keep checking the timing, and remember to chamfer the port edge when you are done so as to not damage the piston ring or piston. Note that 7500 rpms is what is generally accepted as a good max static rpms for the Ryobis due to their relatively weak connecting rod. I will be putting a larger prop on mine to lower the rpms.

4. No modifications were done to the reed valve other than setting the stop at 1/8". No mods were done to the crankcase.

5. Yes, I used a carb with an 11mm venturi, which is a good size for 25 to 30cc engines run in these rpm ranges. The original carb on the Ryobi is very tiny and limits power. I get my carbs off e-bay, and/or from engines I buy from small engine repair shops. Do a search and you will find a long list of useable carb numbers with venturi sizes here in the forum. If you want to find the size of a carb with a given number, you can do so at www.walbro.com

6. When using electronic ignition, the flywheel is left off. With the first engine, (short shaft, small crankcase, restrictive reed valve), this made the engine quite unbalanced. With the new engine, it balanced perfectly without the flywheel, and runs quite smooth. Most people have no balance problems when removing the flywheel on a Ryobi, so I believe the first engine I was working with on this plane was an oddball and not commonly encountered.

7. Note that the Frank Bowman ring provides a nice power gain as well. It reduces the stock ring gap from around .030"+ to near zero.

8. WHEW!!

Here is the plane the engine is in....

AV8TOR
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Old 02-15-2009, 02:26 PM
  #34  
andrew66
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Default RE: Ryobi differences... Comments??

Has anyone tried mounting a ryobi like a glow engine using the bolts for the jug? I still havent got around to running my ryobi that i modified the transfer ports on. If the two bolts arent enough, could i make a small plate that would bolt to the jug with seperate mounting holes, or is the typical setup necessary?
Old 02-15-2009, 02:55 PM
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combatpilot
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Default RE: Ryobi differences... Comments??

av8tor1977. Thanks so much for the info. I know its an awfull lot to get out all at once lol.

I dont see any reason to modify the intake tube on the stock packplate. I also got a carburater off of e-bay and it has the 12.8 mm venturi. It may be to big but wanted to try it anyhow. The intake tube is 16 mm which is what the bore of the butterfly vavle is. the limiting factor of flow in this situation is gona be the venturi which is the smallest part. In other words the intake tube on the back plate is still the largest part of this set up so increasing the diameter of this part will increase the voulume it can flow but wont do any good as the venturi is far smaller. In my opinion it will actually reduce the velocity of the air if it is increased. Bigger ports are not always better. sure you can move larger voulumes of air but at a snails pace.

The gasket thing makes sense and thats what i am going to try also. I am wondering if there can be more improvement in this area. Thanks for the info on port timming I found a pretty good like for this but it still does not have a recomendation for the best port timmings. http://rcfaq.com/ANSWERS/ENGINES/TIMING.HTM they also do not cover the correct way to find tdc which i will cover on another thread. it requires the use of a dial indicator which can be made out of a old spark plug and an in expensive harbor frieght dial indicator. I will show this on my thead also. http://www.rcuniverse.com/forum/m_8479610/tm.htm

I was wondering if the engine would balance without the flywheel. It sounds like the flywheel is balance indepndant of the engine. I dont quite understand how all this fits together without the flywheel. Do you make a spacer to go where the flywheel was? I was thinking just cutting down the flywheel to where i wanted it to be able to mount a magnet in it for the hall affect switch. It would be great to see a pic of what you have done in this instance. Where do you get the magenets for the pickup? I am considering using the ignition set up on hobbyking.com. like i say a complete set up can be gotten for around 40 bucks shipped.

Old 02-15-2009, 03:31 PM
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Default RE: Ryobi differences... Comments??

Ok my mistake on the finding the port timing. I can see now that the timing number is the amount of degrees the crancshaft will turn from when the exshaust port opens to when the exshaust port closes as it is rotated through the cycle. I had the misunderstanding that it was the number of degrees till the eshaust port opened from the tdc as it goes through the cycle.

Anyhow to properly set the timing it will be required to find true tdc.
Old 02-15-2009, 04:13 PM
  #37  
av8tor1977
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Default RE: Ryobi differences... Comments??

The engine should balance fine without the flywheel, unless it is an oddball one like the one I encountered.

You leave the flywheel off. The new prop hub fits on in place of the flywheel, and has a provision for a magnet to trigger the sensor. Sorry, but I don't have any pics at the moment.

AV8TOR
Old 02-15-2009, 04:38 PM
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combatpilot
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Default RE: Ryobi differences... Comments??

Where did you get the prop hub? I really like my paragon one.
Old 02-25-2009, 06:33 PM
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Default RE: Ryobi differences... Comments??

CombatPilot, I also was interested in the hobbyking CDI's.

Besides modifying the ryobi flywheel, what other options are available to mount the magnet (and prop hub) for the hall-effect sensor? Also, since the flywheel is keyed to the crankshaft, how/where do you find the spot to clamp the pickup to the crankcase?
Old 02-25-2009, 09:35 PM
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Default RE: Ryobi differences... Comments??

Well as best I can gather there are two types of prop hubs or shafts for this conversion. The first is a hub that you would use with the stock flywheel. It really dosent work without the flywheel so it is nessacary to macine down the stock flywheel hub to match the prop hub to be able to get a spot to mount the magnet. This is the type I have as i bought a paragon aeronutics conversion kit and the project got benched for a few years. Paragon has since gone out of bussines as the owner has died or so i have heard. As far as where to put the magnet it should go near the same spot as the stock magnet. the hall effect sensor is ussually held to the output shaft housing with a hose clamp and will be now well exposed after machining down the flywheel. if The magnet is located in the same spot as the stock magnet and the hall effect sensor is mounted in the area where the old ignition coil was located then it should all match up pretty good. As far as adjusting the timming of the hall effect sensor it is ussually just rotated on the shaft housing.

The second type prop hub is used without the flywheel and already has or has a spot for a magnet. I have not seen one of these as this is not what I have.

I will be covering this conversion on the ignition on the another darn ryobi post that I have started when I get one of these units.
Old 02-25-2009, 11:39 PM
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Default RE: Ryobi differences... Comments??

it doesn't really matter where you put the magnet as long as you get it lined up with the sensor to be timed correctly... and the hose clamp mounting method for the sensor is normal and easy enough on an engine with a snout like the Ryobi
Old 02-26-2009, 09:03 AM
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Default RE: Ryobi differences... Comments??

Thanks, I'll keep watching this and the other darn ryobi post. I have access to machining tools, and fabricated the prop hub, carb spacer, and mount myself. I would like to machine my own prop hub with a mount for the magnet incorporated into it, but machining the tapered hole to fit over the crank keyway area could be problematic. I was hoping to power a Midwest G202 w/ this engine.
Old 02-26-2009, 11:04 AM
  #43  
tkg
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Default RE: Ryobi differences... Comments??

www.ch-ignitions.com
CH has complete ignition conversion for the Ryobi, we also sell just the timing kits.
Old 02-26-2009, 04:15 PM
  #44  
Racinrc14
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Default RE: Ryobi differences... Comments??

tkg, link didn't work for me.

Anyhow, as it turns out, machining the propeller hub wasn't all that difficult. I just used the compound rest and a very small boring tool to cut the taper. Then I used a set of jewelers' files to file the keyway. Pretty slick actually. I'll post a pic later. Can anyone tell me how to embed a picture in a post?

AV8TOR1977 will any old magnet work for the hall sensor? Counter-boring a small recess in the hub should be quite easy to do, but where can I find the correct magnet?
Old 02-26-2009, 08:58 PM
  #45  
av8tor1977
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Default RE: Ryobi differences... Comments??

Hey Terry, you mis-spelled your own link.... www.ch-ignitions.com (That's why it didn't work Racinrc14, check it out, it is a good link to have handy. They can fix you up.)

Anyway, to post photos, you have to click on the "post reply" at the bottom of the last post in the thread. Using "Fast reply" doesn't enable you to upload pics.

Any decent magnet will work, and there are lots of sources. I have had good luck with 1/8" diameter magnets that I stole out of the end of little give away screw drivers. Radio Shack is a source, as well as the internet of course.

AV8TOR
Old 02-27-2009, 08:29 AM
  #46  
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Default RE: Ryobi differences... Comments??

To post a picture i use a picture hosting site. The one I use is myspace. Ok so you put your pictures on myspace. you can choose there weither you want them public or private. There is also photo bucket, pretty much any site you can post pictures on will work. So when your on your photo hosting site you bring up the picture. Right click on the picture and it will bring up a menu. Select properties. then go to where it says Adress: URL and highlight it and copy it. this is what you will get ie here is one of my pics.

htp://c1.ac-images.myspacecdn.comimages01/26/_0facda2c09fb974da070ced452fb8de8.jpg

ok so now go back here to where your wrighting the post and click on the image button on the message tool bar and you will get this

[img][/img]

Put your cursor right in the middle of the ][ then paste your url adress like this

[img]htp:/c1.ac-images.myspacecdn.commages01/26/l_0facda2c09fb974da070ced452fb8de8.jpg[/img]

ok now notice there is a [img] before and after the url adress. the last one has the / after the [. this is important as it closes it out. this is what you should get when it posts







As far as magnet there are tons of places here is one. I was looking at the magnet on my buddies engine and it is .200 in dia. I dont even think it needs to be recessed and could be epoxied on the shaft. it is so small it shouldnt change the ballance.
http://magnetking.thomasnet.com/viewitems/bonded-neodymium-magnets-3/disk-magnets-2?&bc=100|1096|1099|1113|1041&forward=1


I think the CH ignition cost over $100. The hobbyking ignition is under 40 bucks delivered. I know I dont like it either. I guess the only thing we can do about it is stop voting for these stupid polticians that just cant understand why we cant compete in the world market, due to the fact that we have so much goverment overegulation, EPA OSHA ect ect.
Keep voting for them democrats and maybee it will get better. NOT. Sorry its just the way it is as I am on a thin budget anyhow and really shouldnt even be spending any money on this at all right now.
Old 02-27-2009, 04:30 PM
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Racinrc14
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Default RE: Ryobi differences... Comments??

CombatPilot I feel your pain regarding the diffenence in prices. I looked over the C-H website and read that they use the Chinese-made boxes also. I could get a complete setup (electronics only) for around $80, which unfortunately still doesn't compete with Hobbyking (and I must assume others). Hopefully my other half will let me order the ignition pieces tonight.

Is it realistic to assume that with the right carb. and reed setup, that 7500RPM with an 18-8 is attainable? That would fly this 12-13lb G202 nicely, I think.

I got the picture thing figured out. In the preview post screen it doesn't show the pictures, so I wasn't sure I got it right until I actually looked at the post.
Old 02-27-2009, 04:57 PM
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Default RE: Ryobi differences... Comments??

Yea it really does suck that chinesse products are so much cheaper. Im so tiered of the only buy american attitude. I am sure the CH guy is gona say what a holes we are cause we wont by american. Its not my fault the goverment has made it impossible to compete in the world market so then why should I have to pay a higher price cause our goverment is a bunch of dumb ass clowns that have no clue. I think i would rather just quit paying our goverment to run this ship aground but im affraid there are not enough others to stand with me. I could go on and on on this subject and it is an awfull sore spot lol.

The other thing about ch is the box they offer for the ryobi is not an advancing ignition with rpm and is set to just one point as far as I can tell on thier web site. I really hate to bash an american company but they really dont compare with the hobbyking unit and i sure would like to hear some other view points on this even if it is from CH ignition.

I think I am darn close to the 7500 rpm with all stock parts and a larger carb. I think this ignition will put it over the top.

I like posting the pics like I do it rather than using the upload photo link on the rcu website. they come up full size right away instead of the little dinky pick they put up.
Old 02-27-2009, 05:56 PM
  #49  
tkg
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Default RE: Ryobi differences... Comments??

The orginal Ch package for the weedies had fixed timing. When we started offering the CH-Exl ignition we changed the weedie conversion to the auto advance unit at the same price.
All CH-Exl are warrantied by US and serviced by US. No run around, no problems, no shipping back to China.
We are offering the CH-Exl units to be able to have something to sell for our regular customers. The HD CH units are mostly going to the military, with the occasional one to somebody who only wants the best and is not bothered by having to spend an extra $100 on a $5000 airplane.
TKG


ORIGINAL: combatpilot

Yea it really does suck that chinesse products are so much cheaper. Im so tiered of the only buy american attitude. I am sure the CH guy is gona say what a holes we are cause we wont by american. Its not my fault the goverment has made it impossible to compete in the world market so then why should I have to pay a higher price cause our goverment is a bunch of dumb ass clowns that have no clue. I think i would rather just quit paying our goverment to run this ship aground but im affraid there are not enough others to stand with me. I could go on and on on this subject and it is an awfull sore spot lol.

The other thing about ch is the box they offer for the ryobi is not an advancing ignition with rpm and is set to just one point as far as I can tell on thier web site. I really hate to bash an american company but they really dont compare with the hobbyking unit and i sure would like to hear some other view points on this even if it is from CH ignition.

I think I am darn close to the 7500 rpm with all stock parts and a larger carb. I think this ignition will put it over the top.

I like posting the pics like I do it rather than using the upload photo link on the rcu website. they come up full size right away instead of the little dinky pick they put up.
Old 02-27-2009, 11:04 PM
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Default RE: Ryobi differences... Comments??

My appologies, I stand corrected on the timming of the ch igniton. I didnt get that out of the website. i am not trying to spread missinformation but just relaying what I have seen.

What is the cost of a CH ignition for a ryobi. Just the ignition and a sensor and a magnet? I dont need a prop hub and can modify mine. how much would a hub with a magnet in it already add to the cost?


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