Mongoose beast

Discussion in 'Photos & Bicycle Builds' started by fattirejack, Jan 4, 2015.

  1. fattirejack

    fattirejack Member

    I finally found some time to work on the Beast. I chopped frame up several months ago, Today I got the frame welded back together. I added 12" to lower tube, and added second bottom bracket for jackshaft. I won't need a chain tensioner for drive chain. I will need one on peddle chain. I still need to build motor mounts, springer frontend, and extend seatpost. I hope to have sometime to work on it next weekend.

    Attached Files:

    ElGordo67 likes this.

  2. wheelbender6

    wheelbender6 Well-Known Member

    Cool. Looks like you are making room for a big four stroke in that frame.
  3. fattirejack

    fattirejack Member

    just a china girl for now, who knows what the future might bring
  4. KCvale

    KCvale Motorized Bicycle Vendor

    Wow, that is a radical change in the front fork rake.
    Hard to judge but ~40° right?

    You are going to need some seriously strong front forks to keep that big heavy front wheel from twisting or snapping it, and why you don't see choppers with fat front wheels.

    Spinger forks sound like a really bad idea no matter how cool it would look.
    Take a look at this page for some really great info and pictures about 'chopper' type front forks that will be able to handle huge front wheel.

    Triple trees would probably be the best and least expensive to make, certainly easiest to get the length right.
    Don't forget a disc brake boss or at least V-brake bosses since all the bike has now is a coaster brake.

    Looks like a fun project and I look forward to seeing how it comes out, and more importantly, how it rides ;-}
    Last edited by a moderator: Dec 18, 2015
  5. fattirejack

    fattirejack Member

    2015-01-13 20.46.57.jpg ~37 degrees/3.5" trail, triple trees. Had generator problems over the weekend, kinda set me back. Hope to have the generator back up soon. I can't do any welding without it, unless I weld in the house, that ain't going to happen.
  6. fattirejack

    fattirejack Member

    2015-01-18 15.45.30.jpg Got the springer put together. It rides good for not being completely welded. Some play in front wheel at the moment, Once it is welded solid it should be an awesome ride. Time to start working on motor mounts. Fat tires are great in the snow, and pretty decent on the ice. I felt like a kid with a new toy.. WAIT, I am a kid with a new toy!!!!!!!!!!
  7. fattirejack

    fattirejack Member

    IMG_20150201_132029.jpg IMG_20150201_132031.jpg IMG_20150201_132046.jpg IMG_20150201_132048 (1).jpg
    The BEAST is alive! Took the BEAST for a test ride, lots of fun. Now time to tear it back apart, and get ready for paint. Still a lot to do, chain guard, I want a different tank (probably end up building one), figure out brakes of some kind, different seat, and a rear fender. Got a 66cc on the way, this 48cc was just laying around my place, the cns carb is junk probably only got up to 15 mph. 66 should be here by Friday?
    Doug Foster likes this.
  8. fattirejack

    fattirejack Member

    WIN_20150202_214909.JPG WIN_20150202_215043.JPG
    Thought I would post a few pics before I tear the Beast back down.
  9. fattirejack

    fattirejack Member

    I got my new 66cc at noon today, Couldn't wait to put it on and see what it would do. Took about 2 hrs to pull the 48 and get the 66 ready to go. Spent a good 4 hrs just putting around, wish it was already broken in. Surprisingly the new motor (engine for those that care) pulls this beast rather well, will pull me from a stop with out much trouble. I guess paint might have to wait until we get some more bad weather. This bike is a real blast to ride. Can't wait to get it broke in, so I can see what it will do.
  10. Really cool build

    wow, i really like the looks of that

    great job!

    as to paint, it looks handsome in its flat ratty state, i say keep an element of that
  11. fattirejack

    fattirejack Member

    I was planning on staying with flat black. I need to get some paint on the frontend, and on all the welds. With the high humidity at this time of year it won't take long for the welds to rust. A lot easier to paint before it rusts. Been out riding all day, had to go show the grandkids they love it. I plan on riding it to work in the morning(about 5 miles). Got a tool bag loaded up. I should ride the other bike, but what's the fun in that. supposed to rain later this week, I at least need to get a coat of primer on it.
  12. fattirejack

    fattirejack Member

    2015-02-14 11.41.01.jpg 2015-02-14 11.41.22.jpg
    The BEAST has been painted, still haven't decided what I am going to do for brakes. I think my next project will be to fab up a decent tank. I have a sportster tank, its just to big. I'm thinking along the lines of 1.5 gallons. Haven't done any tin work in many years, should be fun and challenging to make it look decent.
  13. i love the look. nice bike, i need one of those tyres for the back of my chopper
    Last edited: Feb 14, 2015
  14. Arty

    Arty Active Member

    I think it looks great just the way it is.
  15. fattirejack

    fattirejack Member

    Update on the Beast: After 250 miles I noticed some stress cracks on the steering tube welds, added gussets to tube. At 500 miles now, everything seems to be holding up great. Just added rear fender, and taillight. Bike weighs in at 100 lbs., I have minimal vibration with the solid mounts. This bike is a real joy to ride. Max speed is 26 mph, I considered doing some gear changes, but have decided to leave it alone. Riding into a 35 mph headwind last week, I was still able to get 22 mph out of it. It can pull me off of standing start, if I slip the clutch a bit. I would say it is a good trade off SPEED for POWER IMG_20150403_142956.jpg
  16. Iceman2989

    Iceman2989 New Member

    This is beautiful! Well done! Have you tried to ride any in the snow? How has it been? Thanks for the inspiration! :grin5:
  17. fattirejack

    fattirejack Member

    The Beast is still running strong, Didn't ride it much during the winter. With the springer front-end, it tends to push the snow, and slush. It is still enjoyable to ride.
    Today I had the float stick, that happens occasionally. Still running stock plug, and cdi. Not exactly sure how many miles are on it now, odometer keeps resetting to "zero"
    I am on 3rd rear tire, 2nd front. Still running with coaster brake only. This bike is as much fun to ride, as it was to build.
  18. fattirejack

    fattirejack Member

    Replaced primary chain 2 weeks ago. There are advantages to running this short primary chain. The long secondary chain doesn't take much of the abuse of starting the engine, long chain is still in very good shape. Primary was worn out, the way I set up my tensioner requires use of half link (weak link) my half link fell apart when I removed chain. I didn't have another half link, so I welded pin on old one until I get a new one. This is my daily rider. Modified Mongoose Beast frame, 66cc GT5a, .65 jet, 41 roller chain