Design Inspiration

sportscarpat · Feb 24, 2011

Sometimes I run into pictures of vintage motorcycles that really just seem to be perfect. This bike, a Sears vintage motorcycle, really fits my idea of a perfect vintage cruiser. There are so many cool little details on this one. I really like the use of small running boards attached to the frame down tube. This seems like an excellent idea. The pedal crank would be used for kick starting only, then you can comfortably move your feet forward to a relaxed riding position. I also like the layback seat post design and how it also ties into the frame top tube. And those nice deep cut fenders are beautiful. The swept back handlebars and forward mounting of the seat bring the riding position back to a more upright position while still using a stretched out frame for larger engines. A cool leaf spring fork as well. And to think this was available in the Sears catalog in 1915.

sears by Sportsman Flyer, on Flickr

bairdco · Feb 24, 2011

that is pretty cool lookin'.

i've thought of making little footboards before, but my concern is that the cranks could still turn, and you might dig one into the ground on a corner.

i've got some old Wald 3.5" cranks i was thinking of using, but if i ever had to pedal it'd be a nightmare.

sportscarpat · Feb 24, 2011

bairdco said:
that is pretty cool lookin'.

i've thought of making little footboards before, but my concern is that the cranks could still turn, and you might dig one into the ground on a corner.

Interesting you should mention that. I was thinking the same thing. You would need some way of keeping the pedal crank locked into position with a bracket of some sort. It would be a cool build with a Whizzer engine as you just don't pedal a Whizzer anywhere, and if you used the Whizzer centrifugal clutch and a drum brake you wouldn't need the pedal crank to operate a coaster brake.

GTX · Feb 24, 2011

This is one I have always wanted to do with a Morini...

2door · Feb 24, 2011

bairdco said:
that is pretty cool lookin'.

i've thought of making little footboards before, but my concern is that the cranks could still turn, and you might dig one into the ground on a corner.

i've got some old Wald 3.5" cranks i was thinking of using, but if i ever had to pedal it'd be a nightmare.

It wouldn't be too hard to fabricate a friction lock of some design to keep the crank from freewheeling. Heck, just a little rubber stop that could be kicked into place when riding would probably do it.
That is a cool bike, Pat. Too bad Sears doesn't still offer it. I'd be there tomorrow morning.
Tom

sportscarpat · Feb 24, 2011

Hey GTX, that's a pretty cool cruiser, too. One thing I notice on both these builds is the ecentric bottom bracket. I need one that works with the standard 2" bottom bracket. Would make these builds much easier to get both chains dialed in.

bairdco · Feb 24, 2011

like this?

Misc Frame Sup Bushnell Eccentric BB at JensonUSA.com

or this one's pretty cheap:

http://www.google.com/products/catalog?q=eccentric+bottom+bracket&rls=com.microsoft:en-us:IE-SearchBox&oe=UTF-8&rlz=1I7GGLL_en&um=1&ie=UTF-8&cid=9195196601630206592&sa=X&ei=M_dmTfqVKZK8sQO23NmECA&ved=0CCoQ8wIwAw#

sportscarpat · Feb 24, 2011

Bairdco,
That first one is a bit pricey but the second one is very resonable. It says the builder needs to supply a retention system. Shouldn't be too difficult. From there one of those offset arm three piece crank and extra wide spindle should give enough engine clearence. I think a Whizzer engine would be the best choice for an accurate looking replica of the Sears cruiser, and those leaf spring forks keep turning up everywhere I look these days!

bairdco · Feb 24, 2011

if you do a search for "eccentric bottom bracket" there's dozens to choose from, i think the two i linked were the cheapest and most expensive.

a retention system could be as simple as a bolt or two through the BB and tapped into the adapter. or a coupla set screws. i'm sure you could figure out something clean.

i've been looking at these for awhile. there's also eccentric hubs, and chain tensioners out there to adjust the back wheel.

fbmx · Feb 24, 2011

Amazing photo. I love the look of the footboards.

Three things you can do to stop the cranks moving, for some people in BMX this is a problem because on tailwhips and similar no-foot air tricks you want the cranks to stay put.

1. Over tighten the BB. It's pretty easy to tighten the BB too much, sideloading the crank bearings which makes them harder to rotate.

2. Run the chain really tight. On some hubs, like a coaster brake hub or a cassette hub running the chain super tight won't bind the hub driver and will keep the cranks in place. On freewheel hubs this probably won't work. They tend to lock up causing ghost pedaling instead.

3. Grip flange between the sprocket and BB. Probably the best solution. Cut the flange off an old BMX grip and slide it over the crank spindle in between the sprocket and the BB. The drag of the rubber will keep the cranks in place but your bearings and hub will still be running smoothly.

LS614 · Feb 24, 2011

That sears motorcycle is amazing! I want one

sportscarpat · Feb 24, 2011

Hey FBMX,
Good first post and welcome. Those are some good ideas. Hopefully the "f" in fbmx does not stand for "former". I came from the BMX side of bicycles myself, but back from the begining in the late 70's to early 80's. Still have my 1981 Mongoose Kos Kruiser that I bought in 1981. Anyway, welcome to the world of MB's!
Pat

fbmx · Feb 25, 2011

Thanks Pat. I've been checking up on this board and have been admiring your bikes for a while now. Really nice work and that clean black look with raw tanks is right up my alley.

Ever since I saw this blog post on the Vintagent I started Googling and eventually found this forum.

I'd love to build up one of your drop loops with a nice big (fake) crankcase like some of those old racing bikes used to have.

silverbear · Feb 25, 2011

Nice thread and special thanks for the link to Vintagent blogspot. Great historical overview...
SB

fbmx said:
Thanks Pat. I've been checking up on this board and have been admiring your bikes for a while now. Really nice work and that clean black look with raw tanks is right up my alley.

Ever since I saw this blog post on the Vintagent I started Googling and eventually found this forum.

I'd love to build up one of your drop loops with a nice big (fake) crankcase like some of those old racing bikes used to have.

silverbear · Feb 25, 2011

Nice thread and special thanks for the link to Vintagent blogspot. Great historical overview...
SB

fbmx said:
Thanks Pat. I've been checking up on this board and have been admiring your bikes for a while now. Really nice work and that clean black look with raw tanks is right up my alley.

Ever since I saw this blog post on the Vintagent I started Googling and eventually found this forum.

I'd love to build up one of your drop loops with a nice big (fake) crankcase like some of those old racing bikes used to have.

sportscarpat · Feb 25, 2011

fbmx said:
I'd love to build up one of your drop loops with a nice big (fake) crankcase like some of those old racing bikes used to have.

FBMX,
Nice historical photo. A Whizzer engine will fill that loop in one of my frames nicely and it's an engine with pretty cool historical significance, even if the modern version was built in Taiwan. It has a nice big round crank case and is a flat head 4-stroke design.

NE5 1 by Sportsman Flyer, on Flickr

doug713 · Feb 25, 2011

In case anyone missed it in the whizzer section
http://motorbicycling.com/f8/wz001-27510.html#post259087

cobrafreak · Feb 25, 2011

I would have liked to use a whizzer but at 110 cc's it pretty much was too big for CA moped law. It would have upped it to scooter class. Maybe next time.

sportscarpat · Feb 25, 2011

cobrafreak said:
I would have liked to use a whizzer but at 110 cc's it pretty much was too big for CA moped law. It would have upped it to scooter class. Maybe next time.

I was pretty lucky with a 2005 Whizzer I picked up to part out for a future Whizzer build. Bought in California by the original owner who went through all the trouble to get proper registration. It came with a title, all associated paperwork, and most importantly it has a real California moped license plate. The plate will go with the engine to my future Whizzer powered build.

bairdco · Feb 25, 2011

cobrafreak said:
I would have liked to use a whizzer but at 110 cc's it pretty much was too big for CA moped law. It would have upped it to scooter class. Maybe next time.

i dunno where (or why) this still lingers on, but the only cc law that california has is it must be under 150 cc, otherwise it's a motorcycle. there is a 2hp limit, but that's hard to prove.

i dunno what you mean by "scooter class," because with any bicycle with a gas engine, you need at least an M2 license anyway.

whizzers are totally legal here as motorized bicycles/mopeds needing only an M2 license and the rest of the motorized bicycle requirements (plate, lights horn, mirror.)

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