Motorized Bicycle Take a Tip...Leave a Tip

Discussion in 'Motorized Bicycle General Discussion' started by deacon, Jan 15, 2008.

  1. KCvale

    KCvale Active Member

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    This is a tip you might want to avoid. A chain tensioner is just an easy way to make up for chain and sprocket wear on the slack side and never something you want to put on the power side of a drive train.

    If your drive chain gets tight and then loose your sprocket is not true and no tensioner in the world is going to fix THE crucial part of an MB drive train, that being the rear sprocket being true on all 3 planes and if you are lucky you never need some POS tensioner at all to keep your drive chain true and tight.
     
  2. rustycase

    rustycase Gutter Rider

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    I really need to do that, KC!
    Got one bike that is just difficult...
    $5 is a cheap fix!
    rc
     
  3. vincent713

    vincent713 New Member

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    I've tried this method using card board paper from a card board box and indeed it does reduce engine noise however; when riding for a while and the engine gets really hot it starts smoking and burns the card board paper. I'm assuming using this rubber piece will do the same. Any restriction on the engine fins will cause faster heat and will result smokey hot engine!
     
  4. Ludwig II

    Ludwig II Well-Known Member

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    Rubber doesn't burn like cardboard so you'll be safe.

    I've been next to a noise meter when a racing "big fin" Minarelli 50 went past, the exhaust noise was the same as all the other bikes round it, but the fin ringing showed up on the meter as being around twice as loud.
     
  5. MEASURE TWICE

    MEASURE TWICE Active Member

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    Just to catch up and let you know the cheapest hair spray in a dollar store is what I used to glue the twist grip throttle replaceable grip. It does not slip now. I will also put some on the other hand grip as it is probably OK, but could not hurt. The bike shops use this approach I saw in a TV documentary on building BMX bikes. The twist grip replaceable portion is far away from any of the cable parts so there is no danger of having it stick the throttle. I also just sprayed the inside of the grip and pushed it on. I wiped any excess that leaked when I put the hand grip back on. Let it dry inside at room temperature for 3 days.

    Good tip I got from a kids show!
     
  6. OblivionsKey

    OblivionsKey New Member

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    Heres a tip, get a bike with good brakes lol. Also narrow tires seem to make turning radius bigger.
     
  7. rustycase

    rustycase Gutter Rider

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    +1

    If you can't swing disk brakes, or the even more expensive drum brakes, the inline style, or V brakes, are almost a necessity for safety, when you get out in traffic. There is really no way to predict what Others will do!

    Narrow tires might be a good option for an outright speed run in a straight line, on a very good surface. Way back when, Auggie said he was very happy he had selected a medium width tire when he ran at Bonneville. He said the cracks in the salt would have swallowed a narrower tire! NOT gud!

    Yes, turning radius may be larger, because there will be less gripping surface and the tire will scrub more.

    The larger tires also offer some degree of suspension... quite valuable on city streets, driveway aprons, and such. They protect the rim!

    Best
    rc
     
  8. MEASURE TWICE

    MEASURE TWICE Active Member

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    To stop quickly, just don’t go so fast.

    V-Brakes old original have put on my frame after removing the pedals that had the coaster brakes, of which now are both gone, but have fold up foot pegs in their place!

    Also for quicker stops, I have a 40:1 ratio so that the bike can't go too fast anyway. Climb hills good for OHV dirt biking and for parade speed under 5mph have no need to keep pulsing the throttle as the ratio fixes that.

    There is also a screw I have to adjust max speed on the throttle as well as idle. This is for parade speed to be sure it us under 5mph.

    Next mount an Ice Cream Machine in between the sort of ape hanger handle bars, except the ends don’t down point down.

    I should hook up one of then output shafts of one of twin jack shafts turning, for what would be a good speed for an automobile alternator. Or it could easily be something smaller. The charging of a battery set up to then goes through an inverter to power ice-cream machine underway and when engine is off still churning.

    This should be, as well as an art cover looking like a California Sheeps Head Fish and a bell to ring in the 8000ft elevation of Black Rock City, NV so to help with the heat.

    Oh yea training wheels maybe also both front and back using 4ea. 12" tires, no way to fall over...sort of.

    :)

    MT

    .bt.
     
    #668 MEASURE TWICE, Dec 9, 2012
    Last edited: Dec 9, 2012
  9. ahdunno

    ahdunno New Member

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  10. Russ McClay

    Russ McClay New Member

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    Here's my tips about the first time starting the motor which I learned after
    just successfully building my first 66cc motorized bicycle and having many
    (8) unsuccessful attempts to start it:

    First make sure the chain is adjusted, aligned. Walk the bike around, a lot,
    and watch the chain, from the top and from the back.

    If you feel good about it, open the gas line valve, push the float bowl button
    to pre-fill it (if your carb has one) a second or two.

    Move the choke lever up to choke it.

    Then get pedaling at a good speed, pop the clutch and at the same twist the
    throttle to give it gas.

    What a thrill it was to hear that motor start firing!

    The bike starts every time using this method.

    Also, after it starts give it some twists of the throttle and then start lowering
    the choke lever to open it up.

    Last thing, as it warms up you can start adjusting the idle screw while
    releasing the throttle.

    Might as well show off my bike. =) The used bicycle cost me $20.
     

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  11. JTona23

    JTona23 New Member

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    Hi, I'm a year 12 student that is completing a research project. I have chosen to motorize a bicycle using a 80cc, 2 stroke engine. i am looking at ways in which i can modify the bike to optimize its efficiency. I have considered the following:
    - fuel type
    - tire pressure
    - Temperature
    - Spark plug
    - fairing

    further advice on the list above, or any new ideas would be much appreciated. Thanks!
     
  12. Ludwig II

    Ludwig II Well-Known Member

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    From my involvement in cheap motorcycle racing, the very first thing to be done is to rebuild the engine the way it was designed, not how the factory built it on a Friday afternoon.

    The people here who know the engine will run you through the steps required, so you'll be in safe hands.

    There's a job called blueprinting, which means that any unwanted steps or roughnesses in areas where gases flow through the engine are removed. The barrel sits on the crankcase, and there can be edges of the metal of either protruding into the transfer ports and slowing up gas flow. The same point applies to the carburettor and manifold. You will need guiding through those stages.

    Then the reassembly of the engine. Bolts and studs need to be tightened to the appropriate degree and in the correct sequence to avoid leakages and distortions that can reduce the engine's efficiency.

    My team won it's class last year on a "shouldn't have" bike, which had little money spent on fast parts, but hours and hours on fitting and assembly.
     
  13. Wally

    Wally New Member

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    Research? I wonder what field! I have yet to see a 80cc motor. One normal measures the swept volume not the total volume which is what the Chinese like to do. Sounds better. Yes I agree with you LudwigII except Blueprinting is "get it closer to the drawing" One blue prints a standard engine for performance (Racing?) Also I get the impression he wants us to do the research for him :) Why do I say that? There is a tremendous amount of info on these sites (plural) I didn't need to ask any questions with respect to my first build I just read and digested it all. But then again I have been working on cars, bikes and things mechanical for 50 odd years and I am still learning.

    .
     
  14. Ludwig II

    Ludwig II Well-Known Member

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    Another question which needs to be asked is what sort of efficiency are we looking for? Fuel efficiency and greatest mpg, or efficient use of fuel for maximum power?
     
  15. Yankphan

    Yankphan New Member

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    Do the cops bother you ?
     
  16. Wally

    Wally New Member

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    In Cape Town South Africa, No, they look but don't get out of their car. But again I don't ride like a manic and pedestrians have right-of-way I ride mainly on sidewalks, we have quite a few bicycle friendly paths. Although the cyclists are NOT friendly to me. :)
     
  17. SuperDave

    SuperDave New Member

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    Okay, here's my 2 cents worth of "advice".

    I've read through 68 pages of tips & tricks & no one has mentioned this:

    1) That cheap plastic insert that shims the carb to the intake manifold? Pretty much worthless and a potential air leak if you don't get the carb seated firmly against the O-ring. Solution? I used a 5/8 heater hose (about 1/2 an inch worth), trimmed it as straight & flat as I could (where it butts against the carb), inserted it into the carb, and then press onto the manifold. Mine was a VERY snug fit, had to dab a bit of grease on the manifold to get it to go in. Once mounted it was very tight and leak free.

    2) I live in an area that is INFESTED with sand spurs, a.k.a. goat head stickers. With a normal el-cheapo inner tube you'll get a flat in under a mile. So this is what I did: I got a pair of extra thick Slime brand inner tubes. The package claims it's 5 times thicker than the regular kind. I dunno if that's true, but they also come prefilled with self sealing goo. As if that were not enough, I used the original tubes, cut them down the middle (where the rim is) and used that as a liner between the tire & the Slime tubes. Haven't had a flat since. I got mine at my local bike store, and I've notice Wally-World now carries them too. If they're not available in your area, you can try here: http://www.pricepoint.com/detail/16528-345_SLIST7-3-Parts-74-Tubes/Slime-Super-Thick-Smart-Tube.htm

    3) On my aluminum bike, I was a little concerned about the seatpost tube cracking where the motor mounts against it, so I got an extra seat tube, cut the tapered end off (where the seat mount grips it) and sunk it into the bottom of the seatpost tube. Then I added my 1st seat tube on top of it. Had to trim off a little of the bottom to get the seat adjusted for my height, but the added insert helps to reinforce the aluminum frame where the motor clamps onto it, so I feel better about it.

    4) If your handlebars vibrates so much that objects in your mirror appear as blurs, this tip is for you: I took a caulk gun and inserted the tip all the way into the ends and squirted enough to create a stoppage. I let it sit overnight and the next day I filled the ends with sand up to a half an inch from the ends. Squirt with more caulk to seal it in and tape it up with masking tape. Flip it over and do the same with the other end. Give it another day to dry. (Might be best for days you're not gonna ride it, such as wintertime or rainy days)

    5) Replace all the screws and fasteners that come with the motor with American made Grade 8 hardware. I went with black allen bolts, I think they just plain look better. Go to an auto parts store and get Locktite Threadlock BLUE (not red). Dab just a drop on each bolt and let dry overnight before using on the motor. I've had some of the factory bolts loosen on me and once lost my magneto cover, luckily I was able to find it and reuse it. My motor originally came with phillips head screws on all of the motor, they are made cheap, they strip out too easily, and if the heads are that soft, how much better are the threads? Lowe's Hardware in my town carries the largest selection of all the big box stores so I recommend you shop there 1st. Also, the nyloc nuts are no good after the 2nd time installed/removed, so if you have had to remove them more than once, replace them. Chinagirls vibrate something fierce, and weak nuts will back off on their own.

    6) My motor's stock muffler cap came loose on it's maiden voyage and fell off completely before it burnt through the 1st tank of fuel. I suggest a second jam nut over the 1st nut if you intend on running the original exhaust for any length of time.

    Hope this helps someone.
     
  18. Wickedest1

    Wickedest1 Member

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    First let me apologize if this has already been posted, but the crappy front mount u bolt sux...I've swapped that fur an exhaust clamp from the auto parts store...best 2 bucks I spent on this...i could lose my rear mount completely and it wouldn't fall off...mount the ubolt so the clamping bar is beneath your down tube...

    As for me, after every 15-20 rides, I remove the spark plug and dump 2 ounces of motor oil into the engine, let sit about 20 minutes, then with the plug out and a paper towel over the hole, push the bike around to work all the oil into anywhere that may not be lubed enough, then replace the plug, start the motor and let idle for 5 minutes or more...shes gonna smoke like a tire fire but you will be well lubed...
     
  19. Russ McClay

    Russ McClay New Member

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    Hi Wickedest --

    This is a very interesting tip that I haven't heard before. Does anyone else do this?

    Russ
     
  20. Wally

    Wally New Member

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    I am surprised with the lack of comment for or against. Me personally I don't like it dueto the amount of carbon build up from burning motor oil. 2-stroke oil has been designed to mix with petrol (Gasoline) and burn in a conbustion chamber. A fair amount of carbon is produced which is why an exhaust pipe get blocked up. I personally won't do it.
     

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