1950's Vintage Briggs Motorbike Build.

Motorbikermark

New Member
Nov 16, 2011
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Western N.C.
Its the small drive pulley thats slipping. Once I go to the notched belt and a slightly taller pulley it should be good. Thanks for all the encouragement Guys.
 

Motorbikermark

New Member
Nov 16, 2011
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Western N.C.
I actually have it on kind of a sliding rail so as you apply pressure the jackshaft pulley slides backwards applying pressure evenly between the front and rear belts and pulleys. I was using a Whizzer manual clutch but I didn't like the look of the offset pulley or how it was constantly engaged until you pulled the clutch so I made it so the clutch was inline with the drive pulley and the rear sheave, and its disengaged until you engage the drive. Just seemed safer to me.....the idea that a broken clutch cable would result in it being stuck in drive just seemed like a poor idea.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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northeastern Minnesota
Mark,
Talk about patina... it looks like you found your grandpa's motorbike out in the loft of his barn and with just a little fussing... air in the tires and some gas in the tank, some high hopes... and it coughed to life with a putt putt putt. And off you ride into the sunset in the shadow of your imaginary grandpa. A grand illusion you have created and done yourself proud, sir.
SB
 

curtisfox

Well-Known Member
Dec 29, 2008
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minesota
AWESOME!
realy like the old barn find look, just like back in the 50's when all we had was the old Briggs for motors. What is the diamitor of the front pulleys?..............Curt
 

Motorbikermark

New Member
Nov 16, 2011
100
3
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Western N.C.
Thanks Guys, I'm really happy with the way it turned out. Took it recently to a Antique motorcycle show. Had a ball just standing off to the side and listening to people speculate as to what it was. Ironically it just happened to have the perfect backdrop. Curt the front pulley is a 1 3/4".
 
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MEASURE TWICE

Well-Known Member
Jul 13, 2010
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CA
I was just looking at a 5S and 6S Briggs Engines I had not put back together since one of them I had the valves and seats re-cut to the proper angles.

I am using a newer 70's era engine on my off road bike now.
It turns out my lapping before the valves that were re-cut on the newer Briggs probably did not get enough compensation grinding off the bottom of the valve stems. The intake is staying open too long, wasting gas by letting exhaust out the intake a sucking fuel along the way to the air filter. I'm not riding it till I fix that.

Otherwise the JC Penny Foremost fork I removed to swap in one with shocks has some of the nice old character that your marvelous motor bike seen on the street in the picture you posted has.

It was commented about the crown on the old fork from the bike shop I was at. Your bike has the crown on the fork with much a similar look to it.

Maybe I can find some other parts that have that nice aged look and put on of the older cast iron Briggs on another build one day.

I don't have much of any place to work out of the weather and away from where I have those objecting to my working on it, like my apartment, so eventually weekends in cooler weather out side away from my apartment I can start at it again.

Just noticed I have a 1/4 inch diameter shaft on the 5S the slightly smaller displacement older Briggs. I have also a centrifugal belt clutch that I saved also from and old self propelled lawn mower.

It was Motor Mower Company that was painted on the reel mower and also said founded 1919. I know the engine though is mid 50's after they started using governors on the Vacu-Jet carburetors that are with those engines along with oil-bath air filter.

Man that motor bike you built has that old charm!
 
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