My First Build - Racing Bike Style

Discussion in 'Frame Mounted Engines' started by gilesthealmighty, Jul 1, 2008.

  1. Hi there,

    Been kicking about the forum for quite a while now, and only now have i finished my build, i'll take you through it and what bad things have happened, my remedies and other such things.

    Firstly its always nice to have a picture:

    IMAGE_024.jpg - Whole bicycle
    IMAGE_025.jpg - Close up-ish

    I was planning to mount the 50cc HT on my mountain bike but the frame was too big and so i took the easy way and mounted it on the thin framed racing bike (i think it is)

    anyhoo all mounting went ok and after a long while of working out how to remove the chain link it was all set up.

    I went for the pull start method as i really don't like bump starts and love pull starts :) hehe but thats just me

    Bad points so far:

    1. Pull start came apart - Note to all, the little spring inside the pull start, is SOOO long and is like a big clockwork spring thingy, and was a nightmare to put back in!! The source of breaking was the screw coming out, so using two (yes 2) of these locking washers should stop it coming undone.

    2. I have no front wheel - The rats ate it in the shed over the past 10 years .. so a new tyre is needed before i take it for a ride

    3. It makes a funny rattle - I'm not too sure whats causing it, i think that the chain is knocking sideways on the tensioner, as it is not parallel to the chain, whats the best way to tackle this? i'll try bending the metal but its pretty big and i have no tools ..

    4. Kill switch - rigged it up and it went ok, but then saw the topic on using the blue wire so i'll need to change that to that sooon :)

    To Do

    1. Get front wheel
    2. Break it in
    3. Blue Wire Kill Switch
    4. Lights using white wire
    5. Drill baffle after break in
    6. New seat with springs
    7. Locate rattle
    8. Add cardboard behind clutch housing for quietening
    9. Widen cranks because currently the pedals won't turn past pull start ... :(

    Think thats about it! I'll update this post for when things change and such, and i'll get more pictures of any problems i have

    one thing, i'm not quite sure how tight to tighten everything, it all seems tight (i have no locktight, is it available in UK?!) so i might just elecrical tape around the bolts n screws so i won't loose them IF they fall off.

    I really can't wait to get riding this thing!! I started it and took it around the garden despite having no front tyre and it seems so fun! revs nicely and pulled me up my little hill! :) starting on an approx 16:1 fuel mixture, it pumps out a lot of smoke!! And got the idle speed pretty good now! the pull start is awesome despite it breaking but its back now. I also need to adjust the clutch properly.

    Another thing, i read that in the internal gears of the engine (the ones under the clutch housing) they make a lot of noise because the gears are flat, and not at an angle. I looked at mine and they are actually at an angle!! is this common/normal? should extra grease be used?

    Thanks if you read this far, thoughts comments and suggestions are gladdly welcomed, i'm glad to be part of this group its awesome!!

  2. stude13

    stude13 Active Member

    hi; you gotta be tough to ride that, my hat is off. if the kill switch works do not change wires. any brand of thread locker, gasket sealer will work. you need red and blue, different uses. keep after all nuts bolts and screws. put some tape under tensioner clamp. dont overtighten anything. when you can change out all hardware, chain and chain tensioner. later you can, while changing out hardware, you can pull off exhaust and port the pipe. lots of things to keep you busy. ouch, that bike would kill me. good luck mitch
  3. wildemere

    wildemere Member

    To Do

    1. Get front wheel

    Old one might be serviced

    2. Break it in
    3. Blue Wire Kill Switch
    4. Lights using white wire
    5. Drill baffle after break in
    6. New seat with springs
    7. Locate rattle

    That would be the mudguards

    8. Add cardboard behind clutch housing for quietening
    9. Widen cranks because currently the pedals won't turn past pull start ...

    Try raising the install until the pedals clear the cases. Then with the motor raised you will be able to run without a tensioner. A longer set of engine mounts will be needed.

    Also loose the toeclips, major cause of road rash them.

    And get some upright bars.

    See my 27 inch builds here for ideas.

    Old rusty Oxford

    Later model job.
  4. The rims of the front wheel are fine, its just a matter of new innertube and rubber tyre, theyre literally in half and just as cheap to get new ones.

    Yeeep its the mudgaurds thanks for that! Saved me hours of poking and prodding the engine for rattle noises.

    I have been considering that idea and when i get my hand on angle grinder and some metal i will go about that, but for now i see it easiest and by far looking better to simply bend the one pedal to make the clearance.

    Thanks for the tip on replacing all bolts with new ones, i will slowly do that as i work in a hardware store anyway so i can easily obtain them when i next go to work.

    Plans for future are to remove those toeclips, might even do that right now! getting new tyre today so i'll be riding it later on :)

    oh and some upright bars would be so nice! its quite scarey sitting on it in such a low fashion!!

    I think this will go prettty fast!! I can't wait to ride it! Lots of hills in my area so that'll slow me down a bit going up them but i love speed, and i'm assuming that as its a racing style bike its designed to go fast so hopefully won't seize under speed, although its old i have plenty of oil on all major axles and chains.

    Thanks all for the tips, the project is never finished, ever! its always a constant improvement which i think is awesome :)
  5. fastboy9

    fastboy9 Member

    I was thinking about a build like this, a real top speed race bike, that would be brilliant!!

    Constant improvement, exactly the same as me, i'm just never satisfied! Whereabouts in the UK are you from? I'm down south in Essex.

  6. Jakylpops

    Jakylpops New Member

    You could take the handlebars off and mount them upside down so the ends point up at a 45 degree angle, then mount the brake handles upside down so they hang up over the handgrips. Or you could just keep the bars where they are, ditch the stock handgrips and rig up some kind of ATV style thumb throttle that fits up next to the brakes.
  7. Haha nice suggestions i did contemplate that idea but considered that it would look rather silly and well hunkering down low boosts my speed so its great!!

    Been about 60 miles on it so far and no problems! Will post pics tomorrow, but so far its AWESOMEEEEEE!! Top speed 25mph so far, but i'm not abusing it yet i'm sticking to 20mph MAX! :)

    New wheel, pedals now clear the engine, pull start fixed (for the moment), Starting 2nd pull everytime, clutch is being odd atm but i'll let it wear in a bit. Soooo-ooo fun! Brakes are my next issue which i will tackle

    and to answer the location post, i'm on the Herefordshire border. So thats kinda west midlands-ish i'm not too sure on the preciseness!
  8. Paint job time!!


    - Pull start now does not destroy itself .. i hope! Lots of glue etc ..
    - Pedals turn all the way round!!
    - New front tyre
    - Chain gaurd
    - Camcorder Light rigged to run off engine
    - Current rectifier circuit built (Makes AC into DC, so charging batteries, using LED's etc will work without blowing shizzle up)
    - Stand
    - Lots of oil
    - Partially broken in, got through a gallon!! =D
    - painted black (looks so sweeeeet)
    - Avoided 4 police cars so far!

    Things to do:

    - Attach Pannier rack
    - Get tuned pipe/bigger exhaust
    - Smaller back gear (34 teeth? or 36 ..)
    - Get rear brakes
    - Attach charging system
    - Ride more!
  9. JemmaUK

    JemmaUK Guest

    Reminds me of an old raleigh winner 10 speed I had as a kid - the frame is almost identical. I hope you have a good back because that sorta frame could be a real killer..

    Im curious how fast it'll run out - and also do you mean Hertfordshire?

    Only thing I would really keep an eye on beyond the normal stuff is the frame.. engine and road vibration might cause metal failure from fatigue which would be bad. a front springer fork would probably help although it would change the dynamics of the bike a bit..

    have fun

    Jemma xx
  10. fastboy9

    fastboy9 Member

    Very stealthy!! Looks awesome! When you say you are getting a rear pannier rack, have you thought about mounting the fuel tank on to it? Would make it much easier to conceal as you could put it in a bag. Also if you were to get caught by the police then psychologically its easier to blag your way through that it is a Motor assisted bicycle, not an illegal motorcycle! Fantastic job on the bike though, definetely go for a smaller sprocket, and an expansion chamber too! Or how about that new jack shaft kit?? I'm ordering mine next week hopefully, its going to be so good!

    You should post a thread with details on your electrical set up, its beyond me but I'm sure a lot of the guys and gals on here would love to hear more.

  11. (In reply to Jemma):

    The bike must be at least 10 or 15 years old, my elderly neighbour donated it to me, and he's had it a looong time!!
    Nope no typo, no ones heard of Herefordshire! Hertfordshire is 166 miles east of me!

    Currently hitting max RPM of the Happy Time (28mph) gives out soooo much vibration! Even with the uber wide saddle! So i don't rev it like that often, nuts falling off i will see as a problem, and yes i am going to get some front suspension forks, i've hit a few potholes at 20mph and i'm so surprised the forks havnt bent yet! Only time will tell ... new forks will releive some of the impact stress for the rest of the frame to deal with :p

    (In reply to Fastboy):

    You know what, i can't beleive i didnt think of that! That sounds an excelent idea! I will put that into consideration. I could machine a square tank and attach it to the top and providing its thin/flat enough i can still attach my guitar amp to it (^_^) that will add even more to the stealth look!! Which is my aim as if i'm caught i don't think the rozzers will be too leanient .. with it being covered and no sign of a fuel tank who will know better ;)

    Smaller sprocket and expansion chamber are MUST-s! I'll do some searching for vendors, but they all seem to be in the USA so shipping will be difficult .. will see!

    I love the new jackshaft idea, so simple and neat i will wait for others to do it, read their reviews and work out my own opinion, oh how i'd LOVE to be able to use the gears!!!!!

    As for the electrics, yep i will take some photos and post them in the coming week once i've got the battery charging bit sorted, i've seen so many people "say" theyre going to have a charging thingy but i've yet to see one! I'll be the first ;)

    cheers guys highly useful comments much appreciated, happy riding!
  12. softride

    softride Member


    Hi Gils
    I know exactly where Hereforshire is I served with special unit :?::?:there now living in Seattle USA