Another B&S bike

GoldenMotor.com
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
This is a great ride. Built about 6 years ago. Features 5hp B&S (my favorite choice) motor with welded mounts, moped tank-forks-front brake-controls-headlight with speedo, heavy duty spokes, coaster rear brake and a slipper clutch. I bolt the motor in solid with out slotted holes, the belt tension is achieved with the clutch bracket mechanism I engineered on a spring-loaded double pivot to tighten both belts at once. Cool through the frame pipe and mounts were fabbed up by Banzai Machine. Speedo is a little off because it came from a smaller moped wheel. This thing's bullet proof with hundreds of miles on it. It holds up well under my grandson. Very dependable and easy to start. It has one of my internal compression releases that lifts the cam follower up opening the exhaust valve a little. I love these old cruisers.




 
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
Lubing and cooling is no problem. The Briggs motors hold 22 ounces of oil and use a dipper splash system that is not affected by the slight forward angle. I added a dipstick to the filler cap and make sure I don't fill it too much. They are made with overkill cylinder finns, so cooling is easy even without the flywheel finns and shroud. It never overheats. Moving cools it nicely and the oil splash cools it when stopped at idle.
 
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Blackhog01

Member
Jul 10, 2010
52
0
6
Kansas,Chetopa
Man awesum bike !!!!!! ilove the look of your builds just finished mine with a 2 stroke techumseh with belt drive. was it much work to get the moped front end to work? you have to cut it down? different bearings? sorry for all the questions but may have to steal some of your ideas on my next one.
 
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
The moped forks are fairly easy to fit on a Schwinn frame. I've collected a good assortment of bearings and cups over the years and can usually find the correct ones. Sometimes a spacer is needed, but it's a no brainer. The only mod I do to the forks are maybe 1" spacers inside on top of the spring with a hole through the middle and a longer bolt on top. The pipe does have a little plug in the end with a series of holes to knock the noise down. It's really not too loud at all and has lots of power. The clutch consists of a three belt pulley with the center flange trimmed off and a water pump bearing to spin on. The belt guard is part of the clutch as without it, when released, the belt would just lay on the pulleys grabbing and squealing. The mechanism it's mounted on is my design and serves a couple of purposes. It allows you to adjust both belts at the same time, and the lower part is for the cable to be positioned just right. When the belts wear I just loosen one allen bolt and the spring pulls up and self centers on both belts for easy adjustment. Tight the allen bolt back down and your good until next adjustment is needed (not too often). The compression release shaft uses the hole abandoned by the governor shaft. Works great.

 
timboellner

timboellner

Member
Apr 1, 2009
435
0
16
Towson Maryland
Your bike is an inspiration.
It is an example of American ingenuity at it's finest.
Reminds of something that the Wright Brothers could of had a hand in building.
Your bike not only looks like art, but looks functional, sturdy and reliable.
You should be proud of yourself for building something so unique.
Good job man.
I wish more people here had the insight and skills to show off like you have.
Say thanks to your brain for me.
Don't wait so long to show us what you got going on.
I wish you were my neighbor.

TIM
 
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
Thanks for the kind words, Tim, I wish all you guys were my neighbors. We could terrorize So Cal with hundreds of cool bikes. I forgot to mention, on this bike I wanted simplicity, so the only visible wire is the spark plug cable. I start and kill the motor with the compression release. I use a Honda coil with built in advance circuit. The headlight is LED with batteries in the housing. These old Briggs carbs have an adjustable main jet for altitude or power range tuning. The flywheel was balanced on a lawnmower blade tool. The license plate hangs off the rear of the seat.
 
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
I broke the fins off the flywheel with a hammer, then ground down the sharp edges and finished up on a lathe. I have an extra crankshaft and I cut the right side off so I can bolt the flywheel to it and put it into the lathe chuck. After that, I balanced it on a lawnmower blade balancing tool. The compression release is made up of several pieces machined and installed on the inside of the motor. It curves forward and rides a few thousanths above the camshaft between the gear and exhaust lobe. The cam shaft is rough cast, so I smoothed it out on the lathe and that also gave me a little more room. The cam follower is much larger than the cam lobe, so it catches the edge of the cam follower head and lifts it just a little, lifting the exhaust valve off the seat enough to be a compression release. It's activated by a lever on the handlebar through a cable to a lever on the shaft that goes through the bushing that used to hold the governor shaft, and turn a little cam on the inside that does the lifting. a shoulder bolt is added so keep everything straight. I provided a drawing. It's lasted 20 years on the first bike made with now wear or problems.




 
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
Yes, solomon503, my first motorbike build used a Shelby internally sprung fork. Then I was able to buy a bunch of junk mopeds from an impound lot that had all the vin numbers removed. I've been using 70's moped forks on all my bikes since. They look and work great with an inch or so of travel and are not to hard to fit to a bicycle frame. The only problem is mounting a front fender is difficult, so I did without.
 
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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
I purchased several junk mopeds from an impound lot with the vin numbers ground off about 25 years ago and have been using parts from them ever since. Plus, I have found some nice forks on ebay listed as "moped forks". I even went to Myron's Mopeds in Fullerton to buy a set. He wanted $75 compared to around $25-$40 plus shipping on ebay. Wait 'til you see my next build. The forks are awesome.
 
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