Lets do a 40cc ryobi conversion!
 

Alright, since I havent seen any one do one yet, and their on sale......Im gonna convert the ryobi 40cc saw and use electronic ignition.
I was trying to decide between a poulan 42 and this one.After pulling them both over, I chose the ryobi because the compression was MUCH stronger! I will post as much as I can and after Im done I will give total weight, prop rpm etc....hopefully well have a lightweight powerfull engine.Lets get started.......

Here are the first engine pics............suprise, suprise.....the cylinder says ZENOAH.:D

theres some cutting to be done and you could do it with a "hack saw" but Im puttin this in the mill at work .
Also,the carb manifold has those "secondary" intake ports for emission purposes...[:@] but maybe we can block those ports with a new
intake?well tackle that when it comes.You could use the stock coil and magneto if you wanted but its side mounted and its ugly..LOL

RE: Lets do a 40cc ryobi conversion!
 

Where are they on sale at?I want one!What model number or would i just look at the sticker for the specs.

RE: Lets do a 40cc ryobi conversion!
 

I got mine a the home depot for $119....the poulan 42 was $129.

RE: Lets do a 40cc ryobi conversion!
 

oh, also ryobi only makes one saw that I am aware of...and the box says 40cc on it.

RE: Lets do a 40cc ryobi conversion!
 

Thanks,ill call tommorow.

RE: Lets do a 40cc ryobi conversion!
 

HEY....I want one too....its gotta be good...I would think. Lets get on with the conversion!!!! Capt,n:D

RE: Lets do a 40cc ryobi conversion!
 

Nice looking engine-Will be watching this one, please post the weight when you can and details on the conversion regarding mount, carb and exhaust, prop hub, threads, ectt.
Thank-you

RE: Lets do a 40cc ryobi conversion!
 

ok...today I removed the coil and the muffler. The block is now ready for some milling! I cant believe how light the coil and flywheel are.The flywheel is also pretty thin too.Its a bummer there mounted on the side like that. The crankcase is small, as you can see. That should make the engine really want to draw fuel/air.
After the milling is done Ill start the prop hub.Im thinking about a 18-6 for a starter prop...hows that sound?

RE: Lets do a 40cc ryobi conversion!
 

Sounds good to me.Still havent called HD,its like 40 miles to drive there one way so im not going to pop over to see.Looks like it wont be that hard to make a mount.

RE: Lets do a 40cc ryobi conversion!
 

What is the purpose behind the extra intake ports?

RE: Lets do a 40cc ryobi conversion!
 

I bought a refured version from Amazon.com for $109.
The compression is wicked.

If anyone has a lead on prop adapters let me know.
I'm going to set mine up as gas / glow.

Thanks

RE: Lets do a 40cc ryobi conversion!
 

What size are the threads on the crank.

RE: Lets do a 40cc ryobi conversion!
 

What is the plate on side of engine that is held on by 3 bolts...right above the word Zenoah? Thanks Capt,n

RE: Lets do a 40cc ryobi conversion!
 

That plate is on front and back.

RE: Lets do a 40cc ryobi conversion!
 

Alright lets see if I can awnser some of these questions...
The threads on the crank are 8mm x 1.00
The plates on the front and back have ports under them that are directly tied into the portion of the intake manafold that lets air in at higher rmps. This seems to me to be epa related, because the ports under those plates will not be transfering fuel/ air mix.....just air making it run "cleaner" Im not sure how they do this without making the engine run to lean ??
Foamcut, I can make you a prop hub if you want...$25 shipped.
I should have more pics up sunday.

RE: Lets do a 40cc ryobi conversion!
 

Thanks for the info.The thread size is the same as the sachs and if i remember right the 25cc toros also.I(ll go look online and see if my local HD has the saw.

RE: Lets do a 40cc ryobi conversion!
 

Good night
Nice engine, good casting.How many rings have it? I am interested to see the conversion process, and the performance.
Many thanks for your time and posting to the community.
Jose
Argentina
South America

RE: Lets do a 40cc ryobi conversion!
 

Well, milling is almost done...just have to finish up the "detail" work then Ill start the prop hub. As it sits now it weighes in at 2lbs 7 oz.
Im sure I can get it down to 2lbs when i trim the rear shaft off and finish the milling. I think(dont hold me to this) I can have her ready to fly weighing...3.8 lbs
Do you guys think that a respectable weight for a 40cc gasser?
What are poulan 42 coming in at on EI?

RE: Lets do a 40cc ryobi conversion!
 

If it weighs 3.8 lbs with it RTF including ign i think it will be great.A crrc45 weighs 3.63 lbs[dry weight???]what ever that means.Dont know if the weight includes ign.Will have to see what your total cost would be.My home depot doesnt have a ryobi saw[at least on the website].I guess ill call and ask.The crrc 40cc kit weighs 2.87[again-dry weight].But,you made your own and i know parts are going to be easier to get.[priceless];)

RE: Lets do a 40cc ryobi conversion!
 

Hello
How many rings have it?
Thanks for your time to posting
Jose

RE: Lets do a 40cc ryobi conversion!
 

The engine has two piston rings and the piston is domed. I am almost done with the prop hub and will post more pics soon. I took the whole engine apart and the crank is beefy. If it were thinner we cound get the block down to 1.5 lbs...;)

RE: Lets do a 40cc ryobi conversion!
 

I have a 40cc Poulan that has the extra intake port also and was wondering how to plug it? Did your engine come with a Walbro carb. and if so which one?

RE: Lets do a 40cc ryobi conversion!
 

any updates?

RE: Lets do a 40cc ryobi conversion!
 

The prop hub is done...I will take some more pics tomorrow. Next I think I will work on the engine mounts. I need to order the ignition also. Sorry for the delay, but some it always seems like I have 5 things giong on at once;) Oh well, nothing a little medication cant fix!! lol.

RE: Lets do a 40cc ryobi conversion!
 

How hard is going to make a engine mount? Will a flat plate of aluminum work? Thanks Capt,n

RE: Lets do a 40cc ryobi conversion!
 

They're still $109.90 on Amazon and free ship. The site won't let me buy one tho. Says cookies are blocked but they aren't. How's the thrust bearing or can you tell yet? Looking good and thanks for all the info.

RE: Lets do a 40cc ryobi conversion!
 

What is this about thrust bearings? Is this engine a ball bearing engine or a needle bearing engine with a thrust washer? Thanks Capt,n[:-]

RE: Lets do a 40cc ryobi conversion!
 

eeyup- saws don't NEED much of a thrust bearing. A few years ago a club member converted a MAC MiniMac (2.1ci I think). Gutsy little motor but it didn't take long for the crank to eat through the needle bearing cage and lock up. Lucky thing it never got off the ground.

RE: Lets do a 40cc ryobi conversion!
 

I think mac saws are known for having that issue. This engine has two roller bearings at each end so their wont be any issues. Sorry I havent posted anything in the past week on this prodject. I was planning to get something done seeing as we had a long weekend but...as luck would have it ...I spend most of my free time fixing a pipe in my crawlspace that decided it wanted to become a spinkler...and replacing the power steering pump on my tahoe....AGAIN! When I get back to work tomorrow Ill start on it again. It looks like Ill be able to use a flat aluminum plate for a mount but becauseI making a rear dump pitts style muffler, Ill need stand offs as well.I will have more pics up in a day or two.....really.:eek::)

RE: Lets do a 40cc ryobi conversion!
 

Sell the Tahoe as is, turn the water off going to the house and POOOOF all your worries are gone. Now you'll have more time to git-er-done.........

RE: Lets do a 40cc ryobi conversion!
 

Outstanding. Hope the probs are over and looking forward to more.

RE: Lets do a 40cc ryobi conversion!
 

END PLAY...If you can, measure crank end-play with a dial indicator...before you run the engine and after you have ran it a hour or so. Thanks capt,n

RE: Lets do a 40cc ryobi conversion!
 

I wunder if those Hobbycity CDI's for $25 23:D are any good? The sensor is seperate for $7.59[>:]. Wared ya go billzair? Is no news bad news?

RE: Lets do a 40cc ryobi conversion!
 

sorry guys, I fried the circiut board on my lathe and had to weight a week to get the new one. Heres some new pics for ya...its gettin there!I will post more later gotta do some family things right now.:)

RE: Lets do a 40cc ryobi conversion!
 

What are the 2 holes for in black piece above or on carb? Thanks Capt,n

RE: Lets do a 40cc ryobi conversion!
 

Billzare,

That's a nice prop hub. Did you make it? If so how did you bore the taper for the crankshaft end?

Thanks

RE: Lets do a 40cc ryobi conversion!
 

Very nice looking engine so far,great job.My HD doesnt stock them yet.May have to go amazon route.

RE: Lets do a 40cc ryobi conversion!
 

Please show how you plugged off the extra hole for the intake. Thanks. If anyone else has done this please jump in and show what you did.

RE: Lets do a 40cc ryobi conversion!
 

Thanks for all the replies. Captin, the two black holes are the extra "barrels" that let in air a upper rpms. its like I have a 3 barrel carb...lol I want to make a new intake and block these off, but would like to run the engine, add put my finger over those two intake and make sure it dosent kill my rpms first.
I do make my own prophubs, and just use a angle finder to determine about what angle I need to cut. I dont get real critical with this, because there are plenty of treads there to snug it down with no problems.
Sears now carries this saw. Of course its labeled a 40cc craftsman professional series, I believe is yellow colored.Home depot dosent have it any more.
now time to work on the motor mount!

RE: Lets do a 40cc ryobi conversion!
 

Billzair, Does this engine have roller bearings or ball bearings. If rollers you'll have to build in some sort of thrust washer.