Chris's Briggs And Stratton Bike Build

Discussion in 'DIY Home Built Motorized Bicycle (non kit)' started by msrfan, Jun 15, 2015.

  1. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    My grandson and I started building this bike a while back and it got stalled a little. I sold his friend Chris (who owns an off road shop in La Habra) a Schwinn cruiser I found for him at the LB swap. Then he bought a motor and moped fuel tank from me. We kind of put it aside until Chris came up with a large compressor to trade me for the finished bike. Now we're full speed ahead.


    [​IMG]

    [​IMG]



    [​IMG]


    When I say "finished" what i mean is he'll get a running pre-assembly ready for him to paint and detail to his own taste. Of course they usually get ridden for a year or so before that.
    As you can see, it's pretty much my standard design with some different engineered things. Like the clutch holder is a lot more substantial.
    The cutaway side cover is to aid in the installation of the compression release.
    It has a dirt bike front drum brake in moped forks and a moped rear drum and Whizzer pulley. I made a top tripple tree plate to accomodate double bar clamps.
    I made the laid back seat like I did on Bill's Whizzer. It's a standard Messinger vinyl with adjustable springs.

    That's what I have for now. More to follow soon.
     
  2. Tony01

    Tony01 Member

    Joined:
    Nov 28, 2012
    Messages:
    904
    Likes Received:
    15
    Nice! Is that a Chicago Schwinn? Has the flowing connections from the headtube.

    Hey I have a question for you. Are all these Schwinn cruisers the same size? If I redo my motor mount will I be able to fit a 5hp as well? The way mine is right now, I have to really massage it in there to get it in with the spark plug boot on. And taking the boot/plug off is difficult with those seat stays near the head.

    And where do you find these great moped forks? Do they all have a 1" steer tube? Everything that is dual crown suspension type out there for downhill MTBs is very expensive, and I'm trying to find some front suspension that looks good for less than $100.. and not having the lateral flex of a Schwinn springer.
     
  3. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    Yes, it's a 70's Chicago Schwinn middleweight. As far as I know, all the cantilever frames of that era are the same dimensions. The later frames with the welded neck may be different. We've got Myron's Mopeds here in Fullerton for forks. I've found most have a 1'' or 25mm posts. With careful cup, cone and bearing combinations you can make them fit nicely. Placing the 5hp motor in the frame is critical so you have enough room for the spark plug. Which also leaves enough room for the drain plug. May have to offset it to the right more than you originally planned.
     
  4. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,177
    Likes Received:
    5
    Signing on to this thread. I remember the first of your Briggs builds here on the forum. For me it was love at first sight and the use of moped parts (forks and drums) has become standard for me thanks to you. After seeing examples of your Briggs builds and ones by others who were much influenced by your work I wanted to do my own. The "kindalikeawhizzer" build is as close as I will come even though the engine is Tecumseh rather than Briggs... close enough though in size, displacement (199CC) and horsepower (also 5 hsp) to be a close relative. Many thanks to you for sharing your creative energy with the rest of us.

    Chris's bike is already a winner even without detailing and paint. I bet he's happy...

    SB
     
  5. Gbrebes

    Gbrebes Member

    Joined:
    Jul 16, 2010
    Messages:
    568
    Likes Received:
    5
    Cool bike. Very nice looking compressor, should have all the capacity you would ever need.
     
  6. dtv5403

    dtv5403 New Member

    Joined:
    May 4, 2015
    Messages:
    322
    Likes Received:
    0
    my wheel and fork combo is very similar to yours, dirt bike drum in front and moped hub in rear, but I'm running k10 forks and 24" rims with 11g spokes. What size spokes are you running?
     
  7. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    Thanks Gilbert. I hope to get a blast cabinet soon.
     
  8. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    They're 12 ga.
     
  9. MEASURE TWICE

    MEASURE TWICE Active Member

    Joined:
    Jul 13, 2010
    Messages:
    2,026
    Likes Received:
    10
    The clutch that does not go on the engine crankshaft I am curious about. I can see alignment is solved with the jackshaft/clutch arrangement if you call it that, but one question I have to ask.

    My bike I got another engine that is newer an 1/2 hp more to swap in, but I have a problem. I was thinking of possibly using a different engine that has too short a crankshaft for the belt clutch I have. I have looked to buy used crankshaft to fit, but very difficult to find cheap and get all the right spec to match.

    So the other route was to look sort of like what you have. The pulley on the engine crank uses the 1.3 inch length no problem. So here is what I thought I'd try. I put the belt clutch on the jackshaft. Then I realized that the type of clutch uses a live (moving) crankshaft or in this case live jackshaft.

    I could do this, but finding room to place another pulley on the jackshaft and also the belt clutch too, I would have to change stuff around to make room.

    How is this clutch you use have all in one; a way for pulley as input and pulley as output? Is it on a static (non-moving) jackshaft?

    Oh and yea looks like a powerful beast your and friends build!

    https://vimeo.com/130158715 My time before last outing with the 3hp Briggs Bike (maybe to be 3.5).
     
    #9 MEASURE TWICE, Jun 22, 2015
    Last edited: Jun 22, 2015
  10. Ludwig II

    Ludwig II Well-Known Member

    Joined:
    Jul 17, 2012
    Messages:
    4,654
    Likes Received:
    25
    That really looks like vintage motorcycling, with a soft and low revving engine rding down a dirt road.
     
  11. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    The clutch was made for '99 and later Whizzers. I use them on Briggs bikes because the spacing is correct. They're belt to belt with a sprag bearing, along with my compression release, lets you pedal start the engine.
     
  12. MEASURE TWICE

    MEASURE TWICE Active Member

    Joined:
    Jul 13, 2010
    Messages:
    2,026
    Likes Received:
    10
    I'd think maybe out there is a type that may not need the pedal starting feature of the clutch that could be cheaper than Ebay 175 plus shipping from Taiwan, but use a static jackshaft? I'll look around. Thanks!
     
  13. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    Greg and I cut and welded in the gussets, engine mounts, steering stop, tank mounts, and rear brake arm button.




    [​IMG]


    [​IMG]

    [​IMG]


    [​IMG]

    [​IMG]




    Engine assembly coming soon. That leaves intake tube, exhaust pipe, cables and clamps, pedal chain, pedal crank bending, carburetor and a host of small things that should go fairly quickly.
     
  14. scratchbuilder

    Joined:
    Jan 17, 2015
    Messages:
    546
    Likes Received:
    2
    Hey guys i've seen racing karts with the slanted briggs before, what is gained by the slant? I'm looking for a old briggs 2.5 or 3. hp. I've got a 79 pred but the thing is sooo noisey i cant appreciate it. Looking forward to new pics. Thx.
     
  15. maniac57

    maniac57 Old, Fat, and still faster than you

    Joined:
    Oct 8, 2011
    Messages:
    4,486
    Likes Received:
    3
    Mounting concerns or possibly better oiling on the cam (I'm not convinced it does diddly but that's the answer I got from a couple racers)
     
  16. curtisfox

    curtisfox Active Member

    Joined:
    Dec 29, 2008
    Messages:
    3,865
    Likes Received:
    10
    Man this is looking good, sure don't take you long when you have built a couple before.LOL.........Curt
     
  17. silverbear

    silverbear The Boy Who Never Grew Up

    Joined:
    Jul 9, 2009
    Messages:
    8,177
    Likes Received:
    5
    That's going to be a great bike!
    SB
     
  18. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    25 years or so ago when I built my first Briggs bike the 5hp motor wouldn't fit upright without modifying the frame. Besides, I was making a Whizzer copy and liked the look of the tilted cylinder. It provided a snug mounting with room in the rear for intake and exhaust tubes as well as double pulley assembly pivot. Building it on a bet with my friends, I expected it to over heat and seize up with lack of cooling shrouds, flywheel fan, shaved cylinder and oil. Then I was going to scrap it and get back to real Whizzers.
    Instead, it ran nice and cool with plenty of oil splash and more power.
    Briggs engineered their motors with overkill fins and oiling. They knew the neglect they had to endure with the owners never cleaning the grass and mud from the cooling fins or ever changing the oil. So half the fin cooling area and plenty of oil and they last a long time.


    [​IMG]
     
  19. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    Thanks Curt. I've built 6 or 7 of this type over the years so subtle changes come fairly easy. I may change my design for an older look on some future projects, but I have at leas 3 more like this to complete first.


    [​IMG]


    [​IMG]


    [​IMG]


    [​IMG]

    [​IMG]
     
  20. msrfan

    msrfan Active Member

    Joined:
    Sep 17, 2010
    Messages:
    1,703
    Likes Received:
    8
    To me, after riding Whizzers, the pedal start feature was a major requirement. I don't like the look of a recoil starter or carrying a rope.
     

Share This Page