masonman

I have a Ryobi engine off of an old Ryan weed eater.Runs good. It is the engine with the short tapered keyed shaft. I would like to convert it to an EI. My question is. Is there something I'm missing,Is there a number cast in it telling the displacement that it yeilds? One more thing. Is there a place I can by the prop hub with the magnet already installed or is that something I will need to have custom made? Thanks

rangerfredbob

My Feedback: (13)

measure the bore and stroke and find the displacement manually, that's about your only option if it didn't say.

be warned though that some of the older ryobi's are externally balanced with the flywheel, stick the flywheel on a prop balancer and see if it's just mildly out of balance or severely out of balance to tell if it's externally balanced.

masonman

"Holy out of balance engine battman".I don't have the fly wheel anymore. This is not looking good already

Flathead

My Feedback: (11)

The 33 cc engine usually has 10 fins and the top two are square. The 28 cc has 9 fins, and the top one is round. most Ryans have a 33 cc engine as far as I know. Most ot the early engines that need the original flywheel for balancing are "TRIMALL" brand. If you need a flywheel, I might find one laying around. There are seveal companies that make hubs, Jag Engines for one, or you can send the engine to C & H Ignitions in Riveton, Wyoming and the will supply the hub for electronic ignition and set it all up for you. They both have after market mufflers and are good to work with Flathead 4

masonman

Well mine ha s ten cooling fins.About what does ch charge to put the hub an EI on?

w8ye

My Feedback: (16)

The CH kits I have bought were simple bolt on and self aligning for the timing to be perfect with a minimum of fuss.

Flathead

My Feedback: (11)

My mistake, I fat fingered and hit the 3 twice. Should be 31. You can get a phone number for C & H and call them. Depending on what all you want, they have the answers, and always interesting to talk to. Flathead

w8ye

My Feedback: (16)

http://www.ch-ignitions.com/

masonman

Well I'm torn. Not sure if I should keep foolin with this thing. I don't have the flywheel no more, an I'm not sure how its balanced. Is there any distinct marking that would tell if this thing is externaly balanced.I would love to be able to convert this thing,cause it would make for a real clean set up on the RV-4

av8tor1977

My Feedback: (6)

They made a "bizillion" Ryobis, so it shouldn't be too hard to find another one, preferably a 31cc. Try swap meets, garage/yard sales, and my best luck; small engine repair shops. They often have a pile of engines customers never came back for that they will sell you cheap. Look them over good though, as some of the newer Ryobis don't have a case that unbolts and you will have to do surgery on it, and some of them don't have Ryobi engines, they have Homelite 30cc engines. (You will know instantly about the Homelite, as it is side carb, side exhaust.)

Anyway, for your engine, check out this thread I wrote about the balance problem. http://www.rcuniverse.com/forum/m_8313441/tm.htm

There is a picture showing an internally balanced crank, and one that uses the flywheel to help balance the engine. If you want to actually start weighing and checking balance, let me know and I will look up my balance instructions to send to you.

AV8TOR

masonman

Well av8tor, You talked me into it. I hope this is not an "oddball" engine. Have you converted many of the short shaft engines? You seem to have lots of time converting Ryobis. Do you think this engine is a good choice for the Great planes RV-4?.....I was noticing in your pic's.You showed engines with two diffrent crankshaft. Mine has the crank shaft that has the two holes drilled in the counter weight. Is that the crank that would be more pron to being out of balance?....Thanks

av8tor1977

My Feedback: (6)

Hi,

Well, I convert a lot of engines, not just Ryobis, but the Ryobis are neat for narrow cowled airplanes. Unfortunately, if your crank is like the one shown in the picture with two holes in it, it is most probably one that did use the flywheel to help balance the engine. Once again, you might be better looking for another engine. It seems to be irrelevant whether the engine is a long or a short shaft, some just used the flywheel for balance and others not. I believe it was the older engines that tended to use the flywheel for balance assist. Check here in the forum if you are determined to use your engine. Someone likely has a flywheel that you could get on the cheap...

Good luck,
AV8TOR

masonman

.Well that sucks. I will not be using a fly wheel. It will not have the ol mag setup. E.I. is how I want to roll, So I need a new crankshaft then.

av8tor1977

My Feedback: (6)

I don't blame you on the EI, that's what I prefer as well. But, I have MORE bad news for you. If you read that thread I sent you, it notes that the crankcase is a slightly smaller i.d. on the engines that have the externally balanced crank/flywheel combo. A crank for an engine that is internally balanced won't fit the smaller crankcase.

Sorry...

A8VTOR

masonman

Well,Guess I will just have to get away from the short shaft, an get me a long shaft an go from there..........I will find me a diffrent engine an get back with you

masonman

..........WANTED..............One ryobi 31 long shaft. Don't have to run. Just need something to rebuild an convert....If anyone has one collecting dust I would be willing to come off of some dead presidents in trade...Thanks

Ralphbf

My Feedback: (27)

It won't fit with the old bearings.....

How about with new and different bearings.

A trip to the bearing house may be in order.

balsa brain

Masonman, there was a thread on here called Another darn Ryobi thread or something very close to that that was full of very useful information. That may be the one that av8tor sent you. If you can find it it will help you a lot.

masonman

I thought it would not fit cause the crankshaft was to large for the smaller crank case

Ralphbf

My Feedback: (27)

Is it too large for the crank case or too small for the bearings.

I've never dealt with this particular problem with this engine, but
I have done similar things.

It's worth a try

masonman

IM not sure, But I belice the crank won't fit in the smaller case, Not 100% sure, would have to ask avi8tor

masonman

Hey av8tor, Check Out Item #608881 in the engine classified. If its what I need let me now! an I will buy it

billzair

My Feedback: (29)

I have a near new 31cc ryobi. its the complete weedwacker powerhead(the shaft got run over) it is the older style thats all the peices unbolt. if your intrested.....