54 Schwinn 24'' DX My Next Race Bike

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msrfan

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Sep 17, 2010
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Here's some of the stuff I may use for a race bike I'm building. Nothing special. Old cruiser frame and my usual moped parts along with a weed wacker type motor. Haven't totally thought it out yet but it will look similar to my other racer I ran at Willow Springs only the next size down. Trying to break into a smaller class. After seeing scotto racing all day in multiple classes, I should be able to do a couple.


 

MotorBicycleRacing

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Looking good as usual.
What are the specs on that motor?
I presume that it is a 50cc or less 4 stroke?

Are you going with a belt drive?

Here's some of the stuff I may use for a race bike I'm building. Nothing special. Old cruiser frame and my usual moped parts along with a weed wacker type motor. Haven't totally thought it out yet but it will look similar to my other racer I ran at Willow Springs only the next size down. Trying to break into a smaller class. After seeing scotto racing all day in multiple classes, I should be able to do a couple.


 

msrfan

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Sep 17, 2010
1,808
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Southern California
I haven't got that far yet. I'm not sure of the motor specs. Have to check it out. I would like to have a Comet Torque-a-verter on this one but don't know if it has enough power to pull it.

Looks like I'll have to run with the AGK guys in the 100cc class. It's a little over 50cc. Should be fun.




Looking good as usual.
What are the specs on that motor?
I presume that it is a 50cc or less 4 stroke?

Are you going with a belt drive?
 
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msrfan

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Sep 17, 2010
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That's the first thought that came to mind until I got looking at it. The rear fender loop just behind the seat has been somehow ripped out and the tubes leading to the rear dropouts were all bent up. Also being a 24'' helped me decide it would be a good strong choice for my build. I had a 24'' mountain bike frame I was going to use, but it had totally no character. The main reason for going 24'' is because I have these really nice moped drum brake hubs that are 28 spoke. I found some fairly heavy rims and enough of the right size spokes to lace up one wheel. My machinist buddy is shortening the rest of the spokes needed to do the other wheel. They're 1/8'' with large nipples. I plan to clamp the motor in without welding on the frame, so it could be restored to original. It won't be tricked out like some of your bikes, just basic and simple. Thanks for the input. Always welcome.






That's a bit of a semi rare frame to motorize, don't you think?
 

Venice Motor Bikes

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That's the first thought that came to mind until I got looking at it. The rear fender loop just behind the seat has been somehow ripped out and the tubes leading to the rear dropouts were all bent up. Also being a 24'' helped me decide it would be a good strong choice for my build. I had a 24'' mountain bike frame I was going to use, but it had totally no character. The main reason for going 24'' is because I have these really nice moped drum brake hubs that are 28 spoke. I found some fairly heavy rims and enough of the right size spokes to lace up one wheel. My machinist buddy is shortening the rest of the spokes needed to do the other wheel. They're 1/8'' with large nipples. I plan to clamp the motor in without welding on the frame, so it could be restored to original. It won't be tricked out like some of your bikes, just basic and simple. Thanks for the input. Always welcome.
If the frames been damaged?, go for it & weld away!!! (^)
 

msrfan

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Sep 17, 2010
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Thanks for the info. Do you think the motor will not have enough rpm, or power, or both? I wish I knew what the forks are from. I've had them forever but not the rest of the moped.




variated would be cool but the comet variator setup would start to variate WAY too soon for that engine to handle it.

puch forks? maxi or magnum?
 

msrfan

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Sep 17, 2010
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I know what you're saying, but wouldn't it depend on my overall drive ratio? I'm starting with 12:1 which it may pull fairly easily. Also, I guess it depends on what rpm the motor builds power. Okay, I'll do some experimenting. Thanks.
 

MotorBicycleRacing

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Jul 28, 2010
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I haven't got that far yet. I'm not sure of the motor specs. Have to check it out. I would like to have a Comet Torque-a-verter on this one but don't know if it has enough power to pull it.

Looks like I'll have to run with the AGK guys in the 100cc class. It's a little over 50cc. Should be fun.
How much over 50 cc?
It doesn't look like a very large or powerful motor.
What was it off?
Side valve or overhead valve?
What kind of rpm's?
I really doubt if it has enough power to run a Comet Torque-a-verter.

It looks like it could run in the 50 cc 4 Stroke Class......

Is your 5 hp Briggs race bike so hotted up now that you are in the
<11 hp Class?
 

msrfan

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Sep 17, 2010
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It's a 66cc pushrod motor. Got it in a bunch of stuff a friend gave me. I'll have to check the rpms when I get it going. I don't have a clue the exact hp of my Briggs bike. With the milled head and porting I may have gained a couple. All the internals are totally stock so far.
 

msrfan

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Sep 17, 2010
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I got it up on wheels today, thanks to my machinist buddy, Dan. He cut and threaded the spokes I needed for the rear.







He also made head tube extensions so the longer neck forkes will fit. Then he made me special nuts for the rear axle so I can put it on my stand to tune it before riding.




Got my Comet 20 driver in today. It's almost as big as my motor.






Tomorrow I'll work on the kickstand and front sprocket.
 

Don P

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Sep 1, 2010
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HI msrfan
nice build i like very much. i got a 1957 tornado i picked up last week. could you tell me about the hubs you are using what they came from, how many spoked ect thanks.
Don P
 

msrfan

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Sep 17, 2010
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Thanks Don. The brake hubs are from old mopeds. I collected them 25 years or so ago, so I can't tell what bike they're from. I was afraid they were going to go to waste because all my other bikes use 36 spoke wheels. Then I got an idea for a 24'' motorbike and most of them had 28 spokes. So I got a nice Schwinn DX frame down from the rafters, where it hung for 15 years, and fitted the hubs and wheels to it. The front forks are also from an unknown moped, as is the fuel tank. I still have lots of work to do, but I think it has some real nice lines. Is your tornado a 24''? Lot's of options for a DIYer out there.
 

kevinkrg6

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Jun 3, 2011
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Something about bikes like these just look cool....

Is it the straight fork?

And is the frame smaller than what those wheels are meant for?

Can't be just the yellow paint job.....
 

msrfan

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Sep 17, 2010
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Southern California
Today I fitted my Comet to motor adapter to my crankshaft.





It fit perfect.




Got my front brake hub to properly fit the forks.



Installed the rear sprocket onto the rear brake hub.




Then I found some stainless acorn nuts for the fork tops.




Going to work on a side stand tomorrow as well as the front pedal sprocket spacing. I'll try to have more photos soon.