Hello From Sonoma County California

[KevinO]

Hello,

I have a serious addiction to building stuff. I have build small airplanes, cars, motorcycles and bicycles. I really enjoy building bicycles with motors in them. My current project is an early 70's Schwinn with springer fork and a 2003 KTM Pro Senior engine. Here are a few pictures.

 

[Powertool]

Welcome to the forum . Looks like your build is off to a good start.

 

[Wild Bill]

Wow! This will be a ripper! Cant wait to see it finished.

 

[itchybird]

That is a lot of two stroke for a vintage Schwinn. Be sure to wear your best safety gear and hang on tight! You'll need good brakes, especially up front, and a solid rear hub to hook up all that horse power.

I have a lot of saddle time with a Morini S6S in one of my bikes, its a single speed version and its really a damn good motor for lightweight motorized bike. The single speed keeps things civilized, if yours is a 5 spd it'll be a real monster, in which case Simplex tires might be a real good option for you, normal bicycle stuff is way too light for you.

Rich

 

[MEASURE TWICE]

Stop by the grocery store and get a slab of dry ice to slap in front of the radiator

You can then do wheelies around the original bike the engine was on. You just have to learn to steer by leaning.

Nice work so far BTW!

MT

 

[KevinO]

Itchybird,

The KTM motor is the single speed, centrifical clutch model. It is still stupid fast for this application, but should be entertaining.

I still have some tasteful reinforcement to work through on the frame - it is VERY flexible. I do not know how people ride these with event he little 2-4hp motors installed without some sort of reinforcement.

The Simplex tires will be a good investment for durability, but the continental retro ride tires draw so much attention.

The next bike will be even more extreme than this one. It is going to require some serious rethink to make is somewhat safe to ride.

The rear hub has been a bit perplexing. Finding options for gearing and solid mount hubs has been difficult. Even with a 9/62 set up the bike will have a top speed of 48mph. I would like to get that closer to 30mph, but for now just getting the ride sorted out and running properly will be enough for now. dialing in the bike for rideability/fun factor will happen later.

Measure Twice,

The original little kids bike was lots of fun to rip around on, it would pull little wheelies even with my ample hind quarters on it. I am hopeful that the new ride will be the same with better ergonomics.

Kevin O

 

[pdog]

Cheers to KevinO on his build! It seems to me, an extreme Newbie, that your posts on your current build, KevinO, are the very reason this forum is alive. It shows us Newbies how it's done and experienced members can appreciate your work as well as get some ideas for future or current builds. Thank you for your contribution!

 

[itchybird]

We have had pretty good luck with the Moped hubs, specifically the Puch hubs (supplied by Leleu) work well with the Morini motors, the stock offset was a perfect match for my Morini, I suspect it might also be good for the KTM, but measure for yourself. Sprocket sizes were pretty limited, but my brother Pat now makes custom sprockets for these hubs. He also bought a huge lot of NOS lelue hubs too.

The brakes are not as good as some of the modern disk setups I have seen, but the drive sprocket and bicycle sprockets are bolt on pieces which makes them very convenient.

 

[KevinO]

Itchybird,

I have looked at the moped hubs, but have not worked with them at all and have not had any luck with locating hubs in my home town. I have a cycle salvage yard in town but have not had the time to go and poke around to get measurements.

If the morini engine is similar to the denardis air cooled motor then the sprocket offset should be the same. My engine has and offset of ~50mm. I will have to go back and look at my notes to get an exact number.

Thank you for the information on moped hubs. The next build will definitely need them.

Talk soon.

KevinO