2 speedTomos moped engine on bicycle frame

I'm hoping this has already been done by someone... using a moped engine to power a bicycle. Here's the deal: I've been on the lookout for donor mopeds to strip for parts to use on my builds... namely front suspension forks, wheels to rebuild into 26" rims, throttle controls, headlights, speedometers, handlebars etc. So far I have found two. One is an 87 AMF which is going to get left as smaller bike and will get a China girl motor. I paid $45.00 for it. Yesterday I picked up a 1995 Tomos for $125.00. The engine runs nicely, but it is so cold here I can't fool with this bike much at all, and certainly not get it ready to ride. I thought about just fixing it and reselling it, but after doing some research I started thinking about how nice it would be to use that engine on a motored bike build. Here's why. It is two stroke 49cc which makes it legal where I live. It has a 2 speed automatic transmission, Dellorto carburetor with reed valve and tuned exhaust. According to the Moped Army website it can easily be modified to run at 40 or more mph. It has an electrical system capable of running 12v. headlight, tail light, turn signals, brake light and horn. The pedal acts as a kick start. You put the bike up on the center stand, push down on the pedal backwards and it starts the motor. This has been sitting since summer and this morning it started up on the second try at 10 degrees outside.
If there is a way to mount this engine I think I can build a very capable bike for little money. I would swap the wheels with the ones from the AMF since it has 36 hole spokes and the drum brake hubs could be re-laced into 26" rims.

Has anyone done this? Any thoughts from you former moped guys on the feasibility of such a build? Last photo is of the AMF.
SB

Professor,
The Tomos wheels would get put on the AMF and the AMF wheels which have 36 hole hubs would become donors for full sized 26" wheels with heavy duty spokes on a regular bicycle running the Tomos engine. Does that make sense? No title. This has a number of small things wrong with it and I won't know if there are clutch issues unless I get the brakes squared away and try it out as it is. I like the idea of 2 speeds for hill climbing and cruising capability. I know it makes the most sense to just fix and and either use it as it is or sell it. But where's the fun in that? Mopeds don't much ring my bells, but vintage cruisers do. As Msrfan has suggested, then I wouldn't know if it would work in a bicycle. There are a lot of upgrade parts available and even a kit to change it from 49cc to 70cc for around a hundred bucks. I'm not interested in pedaling the bike and with the partial paralysis in my feet & lower legs I can't pedal much even if I wanted to. I'm hoping this has already been done by somebody else who can give some good tips on how to go about it. I'll get a better idea when I see how it is mounted to the moped frame and take some measurements. If this looks like a go I would use a moped rear hub to build the wheel, then change the driven sprocket to get something workable. Different drive sprockets are also available. There would be no sprocket on the right side of the engine and just one chain going to the left side of the hub. Something to think about...
SB

Bairdco, that's an interesting idea about the kick start. It would make it more possible to fit the engine in frame above the bottom bracket. I agree that it makes good sense to get it running decently as a moped before trying to mount it in a bike frame. I think I'll also pick up a repair manual for it. I've read good things about that Tomos A35 engine. If the speedometer is close to accurate it has less than 2,000 miles on it. Once we get past this cold snap and it is in the 40's I can do some work on it.
SB

1937elgin,
First, welcome to the forum! Second, 1937 Elgin is a very good year. I have a real fondness for the old Elgins which had some wonderful designs. I have a ladies 34 Elgin four star waiting for an engine back in Minnesota and last year did a 39.
I'm not sure yet what to do with the Tomos engine, but I am going to use it. I have a 1985? AMF Roadmaster frame I'm pretty sure I can fit it on using the Tomos engine hanger, but I'm open to something else. I'd very much appreciate seeing pictures of your project. Seems like a nice engine... yes?
SB

Cannonball2,
So your Tomos came home to you! Yes, there seems to be a lot available for these engines in upgrades. Since it has the expansion exhaust it could be that the bore is bigger, too. What you describe about walking up hills is what I want. A second speed on my other bikes would make a world of difference. The Moped Army website seems to be a good resource and I found also found a site with members dedicated to the Tomos mopeds.

Professor, if I understand correctly Puch is like the mother company from Austria and Tomos is the Slovenian version of it with much in common and also small differences. So it appears that many parts are common to both and will be available for a long time. That's cool. I imagine the layout on your engine is much like mine.

I have dismantled the Tomos, setting aside parts to reuse on my projects and a few to try to turn on ebay. The problem I see in fitting this engine to a bicycle is that it is designed to mount under the frame, which is higher up on a moped to make room for that. So the engine is set up to hang from above. It seems to me that most bicycles have a frame too low for the engine to hang under the frame. If you were to mount the engine above the pedal crank then there may be issues in having enough room for it in frame. And how do you mount it then? I can see where it would take some modification to make this possible. I'm anxious to see what 37elgin came up with. Being able to weld would sure help... but I don't weld.
SB

Pictured below is the Tomos donor. Keep in mind I bought this for parts to be used in motor bike builds. That it had a running engine was a plus, but not the thing I was originally looking for.

So it got stripped down and the front fork went to a 1953 Schwinn Hornet.

The wheels went to the old AMF roadmaster. In the picture of it with the donor wheels note the way the pedal crank is an extension below the frame and how the frame is high up and follows the same curve as the Tomos frame.

The pedal crank was removed from the AMF, leaving most of the extension it was part of. The engine hanger section of the Tomos frame was cut off and now the engine hanger is roughly in place on the AMF. An advantage to this setup is that I can do it for very little money. The gearing of the rear wheel is as it was... things should line up correctly. The chain may need to be shortened a bit. The AMF frame is simpler, more like a bicycle and is lighter than the Tomos frame. A disadvantage is that it has no rear suspension.

The split from ice damage in the frame needs to be welded (from ice expansion, would you believe!) and the hanger needs to be welded to the frame. I'm not committed to this, but it seems to me it should work OK. I'm open to suggestions...
SB

I'm still not totally committed to this AMF Roadmaster frame, but I think it can be made to work with the main task being the welding. One reason I was thinking about using this was so that I could go through the process of getting a title for it and be able to license it as a moped... not such a big deal here in the states, but if I go up into Canada (not far at all from my place in Minnesota) it would allow me to have a legal gas bike there. Mo other gas bikes would be illegal. On the other hand, I am still curious about using this motor in a vintage bike frame. I'll be very interested in seeing what others have done and decide later which way to go.
mdlee1958, is there any way for you to post a larger photo? I'd really like to see that up close. What frame are you using? What kind of problems did you encounter mounting the engine? Which engine are you using and how do you like the bike?
SB

Just for the heck of it I thought I'd share a couple of the bikes I have that I was thinking might be fun with the Tomos engine. The bike below is a 1939 Hiawatha ladies model. Looks like there might be enough room to mount the engine under the frame. Interesting fenders. I like the fender ornament, of course. It's a heavy duty frame with plenty of room for an inframe gas tank. It
SB would be the only moped like it on the planet. Couple more coming...

First bike below I picked up last summer and is in pretty nice shape, considering. It is a 1942 Schwinn "The World". Last one is not my bike, but the one I have is the same design, different year. This one is about a 40 or 41 Elgin ladies model. Mine is a 34 with a much heavier rear rack than this one. I built a 39 last year with a china girl engine for the rustoration buildoff that got burned in a truck fire last April. I dig the art deco fender skirts. Looks like this one has the most under frame clearance of the three.
Just thinkin...
SB

Wow, you did a great job on your Elgin. What engine is that? It fills up the frame nicely so that it looks like it belongs there. I'll be studying what you did. How's it ride?
SB