My BMX build

Discussion in 'Photos & Bicycle Builds' started by bennyboy, Mar 13, 2008.

  1. bennyboy

    bennyboy New Member

    ok well here it is im new to the forum and the bike isnt quit finished yet though I am expecting maybe this weekend it will get started up for the first time. Only thing stopping it right now is to chop down the drive shaft and to give the guide tube a propper bend to allow it to still spin without any problem. Note though as being the prototype one cant peddle it in this setup you will see in the following pictures.
    Also it still needs breaks figured I should mention that haha. But anyways this is it so far
     

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  2. bennyboy

    bennyboy New Member

    ok so alittle enough on some things prolly first thing is whats that solver thing sticking off the left side of the back tire right well thats where the drive shaft is going to hook into. Oh if you missed my intro post this bike isnt going to be chain or belt drivin it will have a flex shaft drive system :). What you dont see is the frame now has radial bearings and a fiked axel/hub. The rest is pretty common stuff weedeater for motor troybuilt is the brand its a 31cc 2-stroke so I figure what about 2 hp atleast. I can easily pick this bike up with one arm and hold it over my head which is nice since I may bring it inside I do happen to live above a bar and the last thing I need is a fat drunk red-neck trying to take this thing for a spin cause oh it is just to tempting not to. And about the orange around the right grip I cut the grip off and that just happened to be a sleeve off of a PTO adapter I found at the store I work for which got chopped up and shoved inside the rear hub so it would be able to engage the drive shaft head so when I decided I was going to need the grip back on there I just slid that plastic mesh over to hold it on tell I replace the grips with new ones once I get down to the finishing touches like when I make some body panels to help air flow to the airbox which well help sheild it from exhaust heat and hopefully inprove top end performace sense it will prolly act as a air ram at higher speeds will have a nice air filter and everything then I also have to work out a exhaust setup. I dont like ordering stuff sense it so hard for me to recieve the packages in my current living conditions its just a pain in my butt so I am opting to totally custom build this thing so I will prolly join you all in trying to make a decent tuned exhaust guess I should figure out what the air displacement of the engine to figure the proper back presure for the exhaust aslo prolly should take into acount the air box thing I will build and all that but I think I will just take some soft sheet steel cut a pattern .out of it sorta kidney shape in terms that will be just rolled into a exhaust shape and rapped in exhaust repair tape should help keep heat in the exhaust to dont need and burns I figure if it can fix a car exhaust it should handle a 2-stroke exhaust. I dunno its alot for me to figure out but its all got to be rattling around up in my head already. But thats enough talk.

    Here is sorta what I invision for this bike with the paneling and how the front panels will look. Will also help streamline the whole overal bike profile. Hand drawn from by me :)
     

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  3. bennyboy

    bennyboy New Member

    ok last one for tonight well today this is a quick sketch I just did of what the enternals of the airbox is sorta going to be like with prolly screen covering the front openign to keep dirt out or somethin and sheilding to block off that area of the frame inside the panels to make a air box thats away from the exhaust.
     

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  4. Alaskavan

    Alaskavan Guest

    I'm interested to see details of the drive system.
     
  5. bennyboy

    bennyboy New Member

    well when I get home tonight I will sketch up how the drive works. Its really not to complicated the only thing I worry about is power loss at the union to the wheel cause theres gears in that silver thing to change it to an almost 90 degree output.
     
  6. bennyboy

    bennyboy New Member

    I say almost 90 degree because its not sense its the actual weed eater head that would be on the shat its prolly closer to 45 degrees so its at the right cutting angle which is making me think that I will need to turn my engine out a bit more so that the curve on the flex shaft isnt so great it would be nice if it was a true 90 degree then I could just use a sold straight shaft but alas I am working with commonly found parts for this build. I will prolly be posting pics of the drive setup tonight sense I bought a new coupler for inside the hub (same as the current one but I need to cut it up right this time to hopefully get rid of some wobble on the tire either that or my rim isnt true (when it was still a bike the bearings blew out while I was riding the thing causeing some very sore knees and scrapped up calves when it all came apart on me nothing like pushing a bike across town with a locked up rear wheel) Oh well back to work lunch breaks are never long enough. Maybe I will look into the lighting stuff when I get back over to radio shack. Its what I do when Im bored at work that usually gets my projects farther along. You all have a great day. Oh from what im looking at on the bike I may be starting it up tomarrow no matter what.
     
  7. BSA

    BSA Guest

    And there I was thinking you could'nt motorize a BMX. Thats one cool bike.

    BSA
     
  8. bennyboy

    bennyboy New Member

    ok here it goes I drew up what the drive shaft and everything is going to look like I sorta took the wheel apart to fix some things that where bugging me and it has made me change my mind about what I was going to use exactly alittle. So heres what your going to see in the next photos hand drawn mind you. What your not going to see is that the hub of the tire while be secured to the 3/4 inch socket by 3 set screws and the radial bearings are mounted in the frame so the axel and tire can spin still and yeah thats it I think.
     

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  9. Alaskavan

    Alaskavan Guest

    A very interesting idea. I'll be watching your progress. Please take lots of pictures as you go.
     
  10. quarkdude

    quarkdude Guest

    BMX bike motor setup

    Hello bennyboy,
    Welcome to Motoredbikes.com.
    What an awesome idea for motorizing a BMX bike. I thought about it myself, but trying to figure out how to get one in the small "v" of the frame stopped me. Looks like you have figured it out really well, great job. Definitely keep us all posted, we all get into new ideas like yours. I have a Boost Bottle boosted motorized mountain bike here on the site, just do a search on "quarkdude" and the pictures should come up. Again, Welcome to the family. ha ha
    ............................quarkdude
     
  11. bennyboy

    bennyboy New Member

    yeah see thats why I went with the weedeater engine the thing is sideways for the very start so it perfect to fit in the tight frame cause you dont have to worry bout the engine angle as much. I actually already have takin a look at your pics I been roaming round the sight as a guest for awhile so already looked at most hte pictures on this sight haha.

    One thing that I am excited about is that with the socket in the propper postion in the rim it sticks out on the drive side a decent amount pretty much serving as the spacer on that side of the wheel. So I was thinking why not take a metal band secure some rubber to it and make a small bracket to hold it all in place with alittle work I think I could have a functional drum style brake.
     
  12. bennyboy

    bennyboy New Member

    well heres a few of the things I have been working on exhaust, drive train, and rear axel its all just about finished just gotta make like 2 or 3 custom parts and im good to go. I have prolly the messiest work area considering its a small squar of the living room floor I should have a work shop but my brother who I invited to live here invited one of his buddies to stay here too :mad:

    Edit I will post pics later I got 5 minutes to get to work across town you all have a great day bye all
     
  13. graucho

    graucho Active Member

    Vision, its what builds the world. Move it forward. I cant wait to see it unfold.
     
  14. bennyboy

    bennyboy New Member

    well as its unfolding right now it looks more like a small motorcycle and its actually like a light moped in reality sense it no longer functions as a bike so I figure I will be dodging the police. I should prolly leave the wallet at home on the first trip and if I get pulled over say that im 15 and I built it in the backyard haha being 23 with a baby face has some perks. Kids in highschool look older than I do and I been outta that place for 5 years now haha.

    I think the major thing is if the whole drive shaft thing works then its going to be something amazing. When have you ever seen a drive shaft on a bicycle, wait nevermind they make them for bikes already but still this is my own personal monster build I guess. Theres even tools being built into the bike good thing I dont keep a tool box it would be half empty by now. haha well I will post pics soon of the progress.

    the gf just had her gall bladder removed yesterday so she is pretty misrable right now :( figure the most I can do is go comfort her a bit.
     
  15. bennyboy

    bennyboy New Member

    ehhh heres the pics real quick let me know you all think if you recall the hand drawing of the rear axel setup you can see it in the last 2 pics. The hub on the tire slides over that 3/4 socket there in the pics and gets set with some screws and snugs up against that brass bushing. Can sorta make out the radial bearings in the frame and can see how the drive head attaches to the left side (or right in the pics bike is upside down). also there are going to be some additional plates going on each side of the frame to stiffin it back up from removing all the metal to get the bearings in also it will prevent the bearings from popping outta the frame (there is no way to remove the axel without removing the frame bearings so with the plates in place it should be bomb proof) But yeah thats the setu so far pretty much re-enginered the rear axel didnt I.
    But yeah thats the info so far let me know wat you think.
     

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  16. eastwoodo4

    eastwoodo4 Member

    the bend for the shaft looks awfully sharp.gl.cool prodject.
     
  17. eastwoodo4

    eastwoodo4 Member

    plus dosent a weed eater head spin a lot faster than a bike wheel.will it be to high end
     
  18. bennyboy

    bennyboy New Member

    right it is sharpish but its actually straighter than a curved weedwhacker shafter and I have replaced the flex shaft with a thicker flex shaft all thats required with that is making a hex to square coupler to conect the shaft to the engine. and to square the hex on the other end of the shaft to the size of the drive head (got some filing to do working by hand so I can get just that tiny little gap thats required for some locking compound. dont need it comping apart on me.
    Then onto that second point its a major point thats one thing I dont know until I try it out it may requie some gearing which would get ran along the rear frame there and with the axle the way it is now its no problem to flop things around and put a gear right on the axle.
     
  19. Troph

    Troph New Member

    I was wondering what kind of frame that originally was? im going for a frame mount bmx design myself and have been looking into an old frame something like http://bmxmuseum.com/bikes/diamondback/11124 due to the huge gap.
     
  20. sparky

    sparky Active Member

    Troph, read this Crash Course first... and don't forget to introduce yourself in the "introduce yourself" forum.

    As for that frame... it'd either be TOO close or impossible. Maybe if you found something that was 33cc or less. Have you considered rack-mounting the engine??
     
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