80cc Bike Kit on a Wal-Mart 700c Thruster Fixie Bike

Discussion in 'Photos & Bicycle Builds' started by NickNackPattyWaack, Jun 8, 2014.

  1. NickNackPattyWaack

    NickNackPattyWaack New Member

    This is a build thread for my 80cc kit (black) and it's instillation of a Thruster Fixie.
    So far, I have built the engine (from parts), installed it on the bike, ordered and installed new grips, mounted the sprocket on the back wheel, sized the chain, and most importantly broken one of my cylinder bolts in half, and am now waiting for a new one in the mail.
    Here are the pictures of the build. I will upload more when it's finished, (next week or in 2 weeks)
    I will also make a video and post a link when done!

    IMG_0304.jpg 2hyf2iw.jpg IMG_0299.jpg 6zm2r9.jpg 14izal3.jpg 11s37o5.jpg

    All progress will be simply put into the OP as an update, so you all don't need to scroll through to find updates.



    Attached Files:

  2. butre

    butre Well-Known Member

    I'm not big on motorizing road bike frames but that bike would look absolutely sick with the black engine and a billet aluminum head
  3. KCvale

    KCvale Motorized Bicycle Vendor

    You do realize that having a fixie pedal side is going to beat your legs when you use the motor right?
  4. butre

    butre Well-Known Member

    The Thruster 700c has a flip flop hub, I imagine he's smart enough to be using the freewheel side.
  5. NickNackPattyWaack

    NickNackPattyWaack New Member

    Yeah I am concerned about vibration because, using this bike there will be alot.. I am building a sort of motorcycle style bench seat with more padding and plan on putting bigger tires on there though. We will see!

    lol, luckaly this bike does have a wheel with two different sprockets on the back hub, one fixie and one freewheel. I have the drive train sprocket attached onto the fixie, and the freewheel acts as normal.

    That's correct, thanks.
  6. NickNackPattyWaack

    NickNackPattyWaack New Member

    Does anyone know:

    I have broken one of my cylinder bolts trying to torque it down (obviously too much, as the torque wrench was broken) and have tried ordering new bolts 2 times. Each time the threads are different, but not correct.

    My question:
    Can I tap the actual engine so that I can use these new bolts I just bought...

    Let me know what you all think of this idea.

  7. butre

    butre Well-Known Member

    Mine is retapped for all SAE bolts and studs because I had SAE stuff on hand. If you know how to tap a hole you can do it.
  8. NickNackPattyWaack

    NickNackPattyWaack New Member

    Here is a Stock bolt, next to a new BGF bolt that I would need to tap for. As you see, they are slightly different in length, will this become a problem?

    I will figure out how to tap it if it looks like a likely solution.. I can get help from a friend who is a welder/machinist.

  9. butre

    butre Well-Known Member

    Which bolt is which? I doubt the length will be an issue, particularly if the longer bolt is the replacement.

    At least in the picture, the threads look the same to me. The one on the right just seems to have shallower threads than the others.
  10. NickNackPattyWaack

    NickNackPattyWaack New Member

    Well... Can't figure out how to Edit my original Post, but I guess for now, I will post here. I have finished this build, here is the video.
    Thanks for looking! :D
    Ask me any questions You'd like.

  11. john doe

    john doe New Member

    Yeah, i have a thruster that I ride quite a bit, and I had considered motorizing it, but I backed out because I really wasnt sure how well the thruster wheels and frame would hold to the engine. Glad to see that it actually does work out alright. What size sprocket are you using? How well does the engine handle steep hills turning those 700c wheels?
  12. no_i_am_aj

    no_i_am_aj New Member

    I'm also building my project on this frame. I like how you fit the sprocket, I was also thinking about doing this.
  13. Timbone

    Timbone Active Member

    I had a Thruster type fixie motorized bike and, though I got it to work rather well, I would not advise it.

    Two main problems: the chainline is very tight. I had to work some crazy spacers on the left side dropout to keep my 415 chain out of the seatstay. I had considerable damage to the frame caused by chainwhip. The spacers also warped the rear triangle which prevented a good centering of the rear wheel in the frame. I never did get a proper chainline and when "freewheeling" (the motor chain riding thru the disengaged clutch) it was never a good smooth movement.

    Yes, it worked but it was far from optimal.

    Second problem: 700c wheels. I did my build on 700c wheels with smooth Continental touring tires. Yes, the ride was good and smooth but there is no room for error. With the added weight and speed it is just asking for pinch flats. I had so many flats and, even when things were going well, you have to be super careful about avoiding any kind of bump, pothole, crack,expansion joint, etc. It's not worth it!

    If you want any kind of reliability, you have to have thick mountain bike style tires with good rim tape and, better yet, thick flat-resistant inner tubes.

    Good luck!
  14. no_i_am_aj

    no_i_am_aj New Member

    I have since upgraded things on my fixie, I found an awesome tire combo and have more rubber on the road. I have logged over 6,000 miles on this bike so it has been upgraded and modified as repairs were needed. I went through 5 different brands of tires before I found this set of Michelin that work awesome and are indestructible. I cant remember the inner tubes I'm using but they also seem indestructible. Of the research I have done it seems hit or miss, some people have awesome luck with the fixie bikes, others not so much.