The Fred G. Sanford Fleet (Next Engine)

It looks like the kid's gonna be busy this weekend. In the wake of the recent Diesel and Chopper builds, I've started receiving small engines from friends and family.
I was offered first a rusty 3.5 hp lawn mower from a good friend, but it looked well past redemption. Didn't pull for crap, and the recoil was already funky... 2 strikes against it out of the gate, which told me enough to let him scrap it. Awful nice of him to think of me first, though.
The first gift I actually took was a Ryobi 31cc from my Dad, and the second was a very old Homelite ST-200 from my Grandad. I may have a larger saw engine on the way from my cousin as well. I won't yet count that chicken, until it's hatched.
This leads me to my first question for all of my worthy constituents here at the forum: Which of these two would you choose, if this were your build? Pros/Cons?

I've replaced the fuel lines already in the Ryobi, and I believe it may only need to replace a broken primer bulb to get a little life out of it. Smooth recoil, good compression. Known to have sat a good while in Dad's storage garage. No idea what put it down in the first place. Looks like the obvious choice, as it's the larger one.

The Homelite is definitely much older. If I were to guess, I'd say 70's. Flithy on the inside, but the gas lines are surprisingly well intact or already replaced prior to my receipt of it. Pulls harder than Hades, but still rolls over with a good punch. Still won't start. I think it may have ran too thin, too long? I'm no expert, but it seems likely. This one will definitely be the harder of the two to get running, but I'll dive in if it's worth the trouble.

I'm happy with the Diesel as my A-to-B ride, yet already scheming on my next project. No idea what frame I'll be motorizing, but I see these are popular engines for many friction drives. I also have no aversion to going chain drive, but not sure how effective these would be in that application.

(Both engines were tested as is, then torn down for a quick inspection.)

I suppose my question is, which would be more reliable and/or easier to maintain? I've no experience with either of them yet, but I feel pretty lucky to have them fall into my lap thanks to the kindness of others.

I'll gladly read and consider any relevant opinions on the subject. Thanks, all!

Thank you for the useful vids, Mat man. I know that particular Briggs sat outside for months in as much as 15 feet of snow before the thaw. My muffler came from a better Briggs still running (6.5hp), but the shaft was bent. I do know how good they are when well maintained. This was not the case with the one in question. We've always had one around here to cut the grass, though. Another caveat: my small body requires a small frame, and I have a feeling the balance would be screwy any way I managed to mount one that large. Ideally, I'd like to make another 20". Really depends more on what I can get at one of the local salvage yards or secondhand at a good price.
I've run out of frames other than my old school stock Stingray, and I can't see myself being brave enough to motorize it in the foreseeable future. That was my first 20" when I was a kid, so it's a sentimental thing. Just couldn't do it.

Also, anything over 100cc must be insured and registered as a motorcycle in MI. No dice, even if I wanted to.
Just curious, is your username a wrestling reference? I only ask because it made me think of my days on that line in the middle of the mat. I dig.

Well done, guys! Both replies are spot on.

My cousin made good in a big way, and brought me a Homelite XL saw today. Says it might only need a spark plug, but haven't torn into it yet. Orange always did look good to me for an engine. Funny how that worked out. I'm thinking this will be the power plant for the next one. I was fairly sold on the Ryobi until it showed up. May even go the in frame route with the XL if I can find one it will fit into. Let the Fleet begin!

Forecast says rain for the next week. I have the week off and it's gonna rain the whole time. Good a time as any to search up a fitting frame and get the chain drive saw bike started.

The rain giveth, and it taketh away.

Finding the right frame is going to be a quest. If I plan to go stay in my normal 20" realm, it would have to be a very unique frame. I hate messing with frame integrity, so the search continues...

Mountain bikes are too tall for me, so that would just be a balance battle from the start. It would fit though, disappointingly. An OCC would work perfectly, but I'm not going to buy a new bike for a project. The plan should be relatively easy to execute compared to the last DIY, once I find a suitable platform to build upon.

I scrounged together a few rims and tires. A set of mismatched 20" rims, and a nice set of 16" dirt bike rims and tires. The suspension fork needs handlebar hardware, but planning to use it as well. If I do use the old dirt bike set, I already have a sturdy drive sprocket.

Figuring out which front braking system it will have and how that will be feasible should be fun. This makes the dirt bike hubs even more attractive. Though it means I likely won't have pedals in the end, I'll have to register it as a moped anyway. Not a deal-breaker. The design is coming together well so far in my mind and on paper, and that's usually a good indicator of the build. I'm pretty geeked to see this thing materialize.

There are always unforeseen issues, but the ones you can catch early in design are less you have to deal with during the construction phase. Don't rush a good plan and make a conscious effort to get it right the first time.

Thanks for the suggestion Turnofftheradio- I did consider it. Not out of the question, either. A step through would be a good candidate. I just haven't seen one yet. My brother isn't coughing up his Classic step through Stingray, and I wouldn't do it to my fastback, either. I tried, even though I knew the answer before I asked the question. Can't say I blame him. Glad I did though, as he did offer up a BMX that I gave him a while ago and haven't seen since. Didn't know it was still around, so I'm giving it a once over when he has a minute.

I did run across a Cruiser frame abandoned in the street on a short ride this morning, but I figure that one is best left alone. If it looks stolen, chances are it likely is- and this one sure did. Seat missing and the usual vandalisms. Shame too, because I really dig silver. I'm going to measure up a couple more frames I've been looking at today- one the aforementioned BMX, one an old Scwinn Skipper my Aunt found abandoned on a baseball field at work. (I know, I know... Trust me, it's in rough enough condition to be considered.) The BMX may fit, but it will be a close one if it does. The Skipper is a really small bike, but there looks to be enough room for the saw in the frame. If I'm forced to choose an evil, I'd rather be lower than higher on something like a MTB or cruiser.

I think I'm going to use a straight piece of square stock for my handlebars on the suspension fork, as it has no mounts aboard for them. If it works out, it should look pretty tough.

Basically, the first frame I find with enough room to mount the motor solidly will be the direction I go with it from there. I'm working with the same budget as my last build- I hope to do this one using free/found/contributed items as much as possible. I don't think I'll be lucky enough to build another completely free bike, but I've got a lot of stuff compiled already. Call me crazy, but I'm gonna try.

There are certain things I'd like to accomplish with it, but I'm willing to adapt the game plan accordingly. The forks I can live without, as much as I do want them on it- but this NEEDS to be chain driven. On windy, rainy, and snowy days (no stranger to riding in any conditions), it sure would be useful.

I got the XL running! The tank was bone dry, and the air filter wasn't the cleanest; but a good shot of premix and a dozen pulls later it runs like a top. Didn't have to touch a bolt. That's one huge prerequisite out of the way.

After mocking it up on a few different frames, I find the exhaust to be in exactly the wrong place for an in-frame build. Even attempting to put it inside a huge mountain bike frame, the muffler would be directly behind the clutch and in the path of the chain. It's looking more and more like I'll end up with another rack design similar to the last, aligned differently for chain drive. I was so hoping for it to work inside, but this opens up the options quite a bit as far as my frame is concerned. Odds are good on a BMX again.

Thanks, CF. I was already heading down that road. I'm pulling the muffler today to find out. If the pipe/flange that remains is small enough, I may be able to work around it.

This is what I'm looking at. The exhaust port is almost as large as the clutch, so adding some length to the pipe won't solve my problem. It would still be in the way of the motor sprocket if I mounted in the frame.

If I can't think of something better by the time I get back from checking out another BMX, I intend to bite the bullet and build above the back wheel. It seems to be the most practical way without climbing these extra mountains. (Rats...)

I picked up a nice little step through Mongoose BMX today, thanks again to my Grandad! He ran across this underneath a pile of other stuff in his junkyard, and put it aside for me. So nice of him. It cost me a favor in the future, but well worth it. I was sold right away once I saw the suspension already on the front.

Everything is in working order, except the back tire tube. Pretty light, but looks sturdy. Took a nice spin around the block before the tire went down again- very comfortable compared to my usual rigid frame.

Here she is, just as I received her:

Good thinking, Curt. The stock exhaust is a box type, with a hole out the bottom of the two halves. I might be able to fit a pipe inside and work it down from there, if I can form it to stay flush inside. The motor runs, the bike is rolling again and ready, and I still haven't found a solution to work. Taking a little cruise on #1 to clear my head, and hopefully come up with some fresh ideas.