Playing With Copper - 3G Fat Tire 4-Stroke Build

Discussion in 'Photos & Bicycle Builds' started by Leroybrown420, Jun 1, 2015.

  1. Leroybrown420

    Leroybrown420 Member

    Working on a new 4 stroker project and the damn muffler wont fit. What to do? No welder. I came up with a solution that I'm hoping holds together.
    PART_1433202635638_0601151642.jpg PART_1433202650993_0601151642a.jpg

  2. The_Aleman

    The_Aleman Active Member

    If I'm not mistaken, that looks like the small Briggs cigar muffler. I don't recommend using that muffler on a HS, it's extremely restrictive above 5000RPM.

    Better to use the larger Briggs cigar (the 4-7/5-8 version). You get great flow, good sound, and it's just restrictive enough to enhance torque due to backpressure.


    Edit: old video of my bike running, link:
  3. Leroybrown420

    Leroybrown420 Member

    I was looking at that muffler. Rated for 5+ HP. Before I make the final solder I might pick up the other muffler and an adapter. Is the other other muffler 1"? The one I used is 3/4 thread.
  4. The_Aleman

    The_Aleman Active Member

  5. will solder hold up to the heat of the exhaust?
  6. KCvale

    KCvale Motorized Bicycle Vendor

    Regular plumbing solder may hold up, but steel and copper and don't bond well.
    Silver Solder will work but you need a pretty good torch to use it, you have to get the pipes to 700F.
    Here is help for it. soldering.html
  7. Leroybrown420

    Leroybrown420 Member

    I ended up brazing the upper joints and used silver solder on all the lower joints. So far, so good. Dual 1/2 thread mufflers solved the high RPM restriction. Sounds awesome! Would I do it again, hell no.
  8. Leroybrown420

    Leroybrown420 Member

    Last edited by a moderator: Dec 15, 2015
  9. Leroybrown420

    Leroybrown420 Member

  10. Leroybrown420

    Leroybrown420 Member

    When I got the bike the owner had attempted to retrofit a rear engine mount. It might of worked it it was level and/or straight.

    Also found a wasted rear hub bearing and the typical grinding of the throttle grip pin.
    PART_1433948323259_0527151132.jpg PART_1433948474787_0527151138.jpg

    The owner was not happy about the engine mounting in the frame. A 415 Chain Link Pin makes a great throttle grip pin.
    PART_1433949285738_0527151133.jpg PART_1433948806840_0531151536.jpg

    Pedal Power back in action.
    PART_1433948833911_0530151503.jpg PART_1433948858461_0531151531.jpg

    First roadtest blues. Lost a nut.
  11. The_Aleman

    The_Aleman Active Member

    Ugh, with that gearbox, that's likely just the first of many problems to come. They aren't known for being reliable.

    You might want to start looking into finding a more reliable one. There are 2: the Huasheng (keyless tapered shaft) 4G and the Q-Matic with tapered shaft adapter.
  12. Leroybrown420

    Leroybrown420 Member

    I know. That's one of the many problems of finishing other peoples projects. You never know what their going to drop off. Then they want the bike to go 60 mph and as reliable as a Honda but wont spring for a front brake. Some peoples logic drives me mad. That's when I tell them to buy a motorcycle or scooter.
  13. butre

    butre Well-Known Member

    steel and copper bind just fine if the steel is roughed up first.