2 speedTomos moped engine on bicycle frame

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
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northeastern Minnesota
that hiawatha is so cool i can see it with the a35 tomos with a top bar gas tank omy you got any old frames for sale?
1937elgin
I may be selling a few old timers this summer. Too many bikes to ever do them all. I get ahead of myself sometimes. The three bikes I showed pictures of (and the Worksman, too) are all in Minnesota. I only have two bikes here, one I'm riding and the other as a build in progress. I may be coming into a few more old ones this summer and will let you know then if you want. I do like the old timers.
SB
 

cannonball2

Well-Known Member
Oct 28, 2010
3,682
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Colonial Coast USA.
Just thought Id throw this in since this is kind of about a Tomos. Just got the new rings installed (my son broke the old ones trying to free them up), cleaned the carb, and got her running. Runs great! Modded the exhaust a bit and it shows an honest 38mph on the flat. This is about as perfect as a 21yr. old moped gets.
 

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Wow, that looks like a new bike! Bet you're glad now that it sat neglected for so long. It was waiting for you...
I like those spoked wheels so much better than the later magnesium type. So what did you do to mod the exhaust. That a stock engine, yes? What model is it?
I did some engine cleaning today so that I can box it up until summer when it will get painted black to spiff it up. I also removed the Biturbo exhaust and cleaned that up. The Worksman I'm thinking to put it on is in Minnesota, so nothing will happen for that bike until I'm home again. This is the time to research and firm up plans. I may go ahead and clean the carburetor while I'm here so there is one less thing to do this summer. I left the wiring harness attached to the engine and will reuse the brake controls, switches and throttle.
SB
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
1937Elgin,
Can you tell me if the Tomos A35 is the same length front to back as the Puch? The Puch looks longer. I like that your A35 sits a little lower in the frame than the Puch. I'm guessing then that the engine mount tabs are longer since it isn't right up against the cross bar under the gas tank. I'm trying to convince myself that the A35 would fit in the Worksman frame. What do you think?
SB
 

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
Wow, that looks like a new bike! Bet you're glad now that it sat neglected for so long. It was waiting for you...
I like those spoked wheels so much better than the later magnesium type. So what did you do to mod the exhaust. That a stock engine, yes? What model is it?
I did some engine cleaning today so that I can box it up until summer when it will get painted black to spiff it up. I also removed the Biturbo exhaust and cleaned that up. The Worksman I'm thinking to put it on is in Minnesota, so nothing will happen for that bike until I'm home again. This is the time to research and firm up plans. I may go ahead and clean the carburetor while I'm here so there is one less thing to do this summer. I left the wiring harness attached to the engine and will reuse the brake controls, switches and throttle.
SB
The bike is a 1990 A35, the exhaust mod was simply to remove the inner baffle. This bike had to face noise emission standards of 70db. The baffle was very restrictive, I removed it and opened the hole in the end plate a bit at a time to 1/2". Made a world of difference in performance. Still sounds reasonable Changed the trans oil(had motor oil) to ATF and the 2 speed is shifting better everytime I ride it. Plan to save $ even if gas goes to $4/gal with this one!
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Thank you guys for the posts. I just saw these last three. Good to hear about the length of the Puch and Tomos engines being the same. I'm still planning to mount the A35 to the Worksman I posted pictures of earlier in this thread, understanding that frame modifications will be necessary. I think it will make a great bike and I look forward to summer so that I can get to work on it. Unless I run across a lower unit with the kick start assembly I think I'll use a folding pedal for the kick start and see how that works out. Should be OK. Thanks again!
SB
 

LS614

Active Member
Dec 22, 2009
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CT and MA
This is a cool thread :D Those moped engines are REALLY shoehorned into those frames but it looks great. I can't wait to see what you come up with SB you always impress me! :)
-LS
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
LS,
Thanks for your kind words. I've learned so much on this forum and been exposed to so many great ideas to be inspired by. Pretty soon your imagination catches fire and you've got some things of your own you want to try. I'm always looking for ways to do things on the cheap or with simple tools, so I have to get creative. It would be nice to just order cool things and assemble it all when it arrives, but having to scrounge and remake things gives a kind of intimacy to a build so that by the time you fire it up and ride off into the sunset on your trusty steed, it really is your pony.
I think this moped idea has a lot of great potential. An old moped like the Tomos or Puch provides lots of parts for a build and the engine is perfect I think with it being within the law, 2 speed tranny, great electrical system, lots of parts and upgrades available and well made in Europe. And yes, I also like how the engine looks "shoehorned" into the frame, as you say. Kick start is cool, too. Now all I have to do is do it. Ha!
SB