Oops, photos...

Steve

No need to worry. The Zama carb will work just fine. I have one that worked OK, but I choose to buy a walbro wt-433($20.00 US) from Peter at wackerengines. It is a little larger carb and feeds the a engine little more fuel and air. And that means more power and RPM,s. With the wt-433 carb and the OPTI-2 oil I am getting 7400 RPM out of my old Ryobi 31cc with a MAS 18x8 prop. I fly around most of the time at half throttle. It will not hover, but I can hold her there for a few seconds before she starts to fall back. When that happens I just give here full throttle and watch her climb.

don't worry about the carb being a zama! most of the stihl products use these as do many others. all my little echo weedies have them too. the pump diaphragm and check valves are made of a better material than the walbro and don't dry and curl up after a long period of no use. be happy

also the numbers don't mean much as ryobi has made millions of these engines over the years. i doubt anyone out there knows what they all mean. your numbers are probably for an "export" product. the important things are number of rings and weather or not it has decompression slits in the cylinder.

oil: disregard what the fuel cap says, they're just trying to cover all bases as this thing is meant to be used by the average dumass that hasn't got a clue. if you have an echo dealer they'll have a nice 50:1 oil. otherwise mix per the oil manufacturers recommendations.

and have fun,

dave

Jim & Dave,
Thank you for the info and reassurance. I owe you both a big beer! Phew... Sorry if I worry too much Can you imagine what'll I be like on the maiden flight of this thing [X(]

Think I'll probably add the WT-433 on to my Wacker order - may aswell at that price!

I was going to probably use a 'good' two stroke motorcycle oil as I know I can get that locally. I understand what you're saying Dave about the 'recommended' 20:1 ratio, just covering themselves huh?

O.k. I'm happy now

Steve

If there is anything else that comes along just post it here. You will always get help. When you buy your oil look for one that will work on all engine's not matter what the mix ratio. I used the Ryobi 2 cycle oil first at a 32:1 ratio and it work real good, but when I tried the Opti-2 oil I was sold and I have never go back. I am running the Opti-2 Oil in all of my 2 cycles engines weather they are for RC or just keeping the old weedwacker running good.

Have a Ball Steve. I know I am

Hi guys,
Just to let you know that after an hour or two with a big hammer I've got my engine stripped Hardest part was the spark-plug - real tight! [:@]

I just need the new parts now, oh, and a plane to put it in lol

Thanks to all you kind folks for getting me this far - you're the best! I think I might have a couple more questions before The R-31 runs so I'll probably be back! But for now I'll leave you in peace.

All the best,
Steve

Purple Pilot
If you want to stay away from the machine shop for the trimming of the fins on magneto...
I got a small metal cut-off wheel (3" dia and the mandral to hold it) and mounted it in my drill press. Set the table to desired height and started to slowly rotate the magneto. Cut those fins off nice and easy. It will not get the the center where the prop spacer would fit, but a larger diameter wheel would. I now have the tool for future use and save the trip to the machine shop.

Oh yeah, if I recall you are getting a different carb. If so hold off on making the carb spacer, required for clearance to mount plate untill you have the new carb. I found that the throttle linkage plate (attached to the throttle shaft) was a differnt size and shape and I ended up making another spacer to get required clearances for throttle to open toally. I think all my future spacers will be from plywood epoxied to desired thickness. Lot easier to work than alum. and a better heat insulator.

Another means (that I havent tried myself) to trim the cooling fins on the flywheel would be to chuck it up in a drill press. Start it spinning and use a hack saw to cut the fins off. I've only heard of someone doing this, havent done it myself. Might try it on my next conversion to see how it really works. Just a thought.
Edwin

You're on the right track, Steve, the larger carb and a less restrictive exhaust will allow your Ryobi to turn out some useful power.

I trimmed off the flywheel fins with a milling cutter in the drill press, after cutting most off with a hack saw. This allowed me to true up the center as well. You're gonna really hate yourself if you didn't keep your dad's drillpress, it's more than a bit handy for this conversion stuff.

By the way, keep everything you remove from the engine. I reused the choke assembly on the bigger carb (mine's a Tillotson), and I used the starter pawls, springs, and pins and recoil assembly to make up a starter.

My Ryobi is in a Balsa USA 1/4 scale Cub that I'll be flying for the first time this weekend. Keep your fingers crossed for me.

Have fun:
Allan

Now that is the most ingeneous starter I've seen. Good going sportflier. Has anybody been able to hand start a ryobi. Someone asked why I use a starter and my reply was because I dont think I can hand start a stock setup. I know other gassers like the G-38 with a mag ignition will hand start, just wondering if a ryobi will.
Edwin

Mike, Edwin & Allan,
Thank you all very much for your posts - appreciated [sm=thumbup.gif]

Unfortunately I don't even have a drill press, although I know I should buy one. I doubt this months budget will stretch to it, what with the conversion parts needed. The good news is that I've been put in touch with a guy who has a small machine shop (a friend of a friend) so I hope to see him next week for fly-wheel modification.

Mike, I noticed that some conversion companies offered the carb spacer while others didn't so it obviously depends on the carb - thanks for that tip. If I can make one from laminated ply then that's cool, I'll just wait until I get the bigger Walbro.

Allan, very neat starter mechanism!

I just need to get in touch with Wacker Engines now; the e-amil obviously isn't working so a phone-call it shall be...

Have a good weekend!
Steve

Jim (jstanton),
Dunno if you're still reading this thread but I've just had an e-mail from Interlube International saying that they don't have a UK distributor for the Opti-2 oil.

I also found out this afternoon that you can't get Gator RC wing-tubes here anymore either (for the 'Ryans Rebel'). Well, one shop had one size left in stock - 48" x 1.5" bare ali version with phenolics... $60!

Thank the Lord for USPS!

sportflyer: I agree that is an interesting starter. would like to hear more about it... Maybe a seperate thread post 'what to do with the leftover weedie parts' he he

Hi Mike,
I just noticed in one of your posts in the 'Tach Readings' forum that you had made your own muffler from an electric junction box. I was thinking of trying the same but have no idea of what size to use or anything about the 'down pipes' - I know the original weedie muffler is about 225cc in volume Do you have any dimensions, images or advice?

Thanks as always,
Steve

Steve:
You might consider modifying the stock muffler rather than making one up from scratch. The muffler in your pictures looks very different from mine, but maybe the ideas would still work. I ground off the crimped over part that held the muffler together and removed all the stock "guts". For the outlet, I used a thin wall steel tube with a 5/8" I.D. (about 16 mm) which I think was a piece of electrical conduit. I reassembled with silver solder which is a form of brazing. Picked up over 400 RPM from the stock muffler, and it doesn't seem to be too noisy, but I haven't flown it yet.

Check out this site, "Teaching a weedwacker how to fly" if you haven't already seen it.
http://www.geocities.com/CapeCanaver...216/index.html

Here's a couple more pics of the economy starter for Mike. It really does work, and you don't have to get as cozy with the propellor as you do with an electric starter.

Hi Allan,
Thanks for the advice and link.

Yup, my muffler is definitely different to what I've seen elsewhere - mine is cicular. Or should I say was I deconstructed that too he, he, so it's not very usable I'm afraid. I intend to buy a new one from Wacker Engines if I can ever get hold of the guy.

Regarding the link to the "Teaching a weedwacker how to fly" web-site it confirms everything I've read elsewhere except Joe Guzzardi says that the flywheel is purposely imbalanced to compensate the piston/crank etc. Now that has really confused me as it seems to contradict other peoples advice [sm=spinnyeyes.gif]

I'm gonna ask the question in another thread I started about which prop balancer to use... so if you'd like to reply maybe that'd be a better place (?)... [link=http://www.rcuniverse.com/forum/Flywheel_balancing_%2D_which_balancer%3F/m_1734528/tm.htm]Prop Balancer Thread[/link]

I might have a go at building one of those starters too

Steve

Pic should give you an idea. FWIW: Plugging (welding) the other conduit opening close added $ and wt. someone mentioned that meta plugs are available for that purpose. If I were to do another, 1) I would try to put the cover plate on bottom vs the back.; 2) use steel brake line for the compression tubes. If memory serves the muffler bolts are #12. Impossible to get locally. Noise is not a big problem here so I'm playing around more now with exhaust 'deflector' vs muffling.

Latest silver sodered and JB weld tubes fell out of muffler this afternoon with just a few minutes run time. Soder just melted both surfaces showed good soder job just too much heat.

Thanks Mike!

Steve

Sorry I have been on vacation for the last 5 days. If you cannot get any Opti-2 oil over there can you get amsoil? http://www.amsoil.com This is another oil that can be used with all 2 cycle engines. Opti-2 oil is only $1.20(US) per package here. If you want I would be glad to send you a package so you can try it out. All you do is just mix 1 package with 1 gallon of gas.

Hi Jim,
No need to apologise Hope you had a great vacation! I have a nice, five-day-long weekend this week and I was planning on visiting this guy to get my flywheel machined. Unfortunately my car had other ideas and decided to dump its gear-box oil all over the road yesterday [] It needs an obsolete part so tomorrow I'll be crawling round junk-yards

Very many thanks for the offer of the oil btw [sm=thumbup.gif] but until I can get the conversion parts...

I sent Wacker another (3rd) e-mail today.

Ever get the feeling that 'someone' desn't want me to go gas???

All the best,
Steve

Steve

Good luck on repairing your car. I know they can be a pain sometimes. Let me know when you need the Opti-2 oil. I'll be glad to send you some. I know you'll love using it compared to the standard 2 cycle brands.

Thanks