what did you do to your motorized bicycle today?

Discussion in 'Motorized Bicycle General Discussion' started by Skarrd, Oct 25, 2010.

  1. Rudz

    Rudz New Member

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    Killed my first magneto today, it confused me at first because the bike ran great, I stopped because the tank had shifted, then I couldn't get it running again.

    Make sure choke was off, line had gas, I was so sad. Pushed her up the steep hill home, tired after working, drenched in sweat.

    After I got some sleep I dragged her outfit, checked the carburetor, line, made sure everything was tight. Then I replaced the spark plug and the magneto.

    I said a prayer, and praise jesus she started right up.

    I put the ngk plug back on and it still fired up, so my plug is good.

    Used my spare magneto, so I ordered another.

    Also, anyone looking for tank mounts for wide top tubes, I found some conduit straps that look exactly like the $6.99 plus shipping, brackets I bought from bikeberry (this is before I heard they were the devil)

    I cracked the original bracket when I bent it to fit, been holding until last night.
     
  2. mapbike

    mapbike Active Member

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    went for a nice ride late yesterday evening just before dark, first time I've even started one of my bikes in a while now, was a cool and relaxing cruise for a few miles down the ole dirt road.

    We've had nice cool weather here in central Texas this weekend, such a welcome break from the upper 90's - 100+ degrees we have been dealing with, some around here are cold when the temps go from 100 down to the upper 50's to mid and upper 60's but this ole country boy like it, makes me feel like a buck and I kinda go into rut just a little andfeel like gettit outside and doing things.

    hoping to ride more as time allows, I'm needing to rebuild the top end of the dax engine on my old 1963 Western Flyer bike, needs new jug and piston, engine still runs but has lost compression due to rings not being seated well and I'm tinking they have lost their tension due to overheating, this is the upper that I run my person best top speed of 50.3 mph with, to many high speed runs on those rings and they have given up the ghost...lol

    The engine has low bottom end power because of the timing changes I made to get the high rpms, I dont care about going that fast anymore so Im going back to a more stock configuration that will give me better torque.

    Happy safe riding y'all.

    Map
     
  3. electron

    electron New Member

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    MIXTURE PAIN, never need to use choke?
    Note, if this is too long, sorry, but how else would u get the whole pic

    First 50cc was stolen a few years ago. Was fast and reliable. All factory (some carb and exhaust manifold matching) inc old style black filter carb with replaced throttle and kill sw. as was the case years ago.

    Now ive seen my mate with his 50cc (27" stock, flies!) and when he gave me a bike (700) i couldnt help myself (80 (66?)cc).
    Sometimes under load it starts to pull hard and "purr". Played with plug gap. Plug lead "head" fell appart: replace with nice automotive lead (unscrews from coil (coil/cdi). Less speedo interference, few dollars, may need to be reduced in thickness at coil.
    As allways i started messin with it too early, slowly increasing speed for short moments, playin with the needle. Soon to come down to 20 to 1 (200km). I think 16 to 1 is extemely oily. Ill soon compare 30 and 20 to 1 to c how it compares in performance (stick with 20 if neglagable difference). Plug has been black and oily during all conditions (flash tests, or whatever theyre called) for all needle settings, which is strange and i never need to use the choke?. China plug, but ive never had a prob with em, the coil/cdi or magneto. May consider ngk for after run in fuel mix. Ngk 6, 7 8? for south australia (med hot, dry), bpr7hix (with washer if u hav high comp head) or bosch wr7ac. Im guessin 6 is too hot. Need a spare is my excuse.

    Prob should have stopped messin with it untill i was on my final running mix, but even though its obviously too rich and chocking on all that oil, i read about .8mm jets and blindly decided i will drill out the jet (nothin to loose). This made it worse, of coure. I need more air!

    Dont really want high compession issues (although cooling may b eventually beneficial) or to spend on exhaust, carbs, gears, balancing, major engine work. Chaint tensioner and Solid rear hub mounting would b nice, but kit style can b satisfactory. Run the best fuel, why not, it s peace of mind.
    Did 43kms p hr (44t) briefly a few times and the vibes are reducing to very smmoth now.

    Most of the time it sounds like a 2 stroke, but sometime, often under load such as uphill just starts to pull hard and "purr" (thats not 4 stokin is it?). So opened up the 2 manifold gaskets, bit better. Take off exhaust cap, just more noise, too much, no back pressure.
    The kit i got had the old black filter carb, bummer i thought. Open it up 2mm dia. and insert o ring as manifold seal, more low end power. I had opened up carby so much that an oring would have been the limiting factor, remove o ring. Still good torque.
    What about this exhaust, drill holes? Weld in curtain rod? Bugger it, cut the removable pipe (an aside, im still waitin on the replacemrnt exhaust i was promised, as my end cap and a weld leaked) and drilled out the remainder inside retaining the outer and weld, of course. Bit louder, dirt bike sound than i wanted (agressive and attracts a bit more attention, even when slow cruisin (which helped a bit today with pedestrians) and heaps of torque!

    Today After a few more 43kph (27mph) spurts i got home and52.5 (33mph) was on the speedo (accurately calibrated). Sure their were a few declines and i did pedal hard.

    Must leave it for now, but my can is empty of running in mix and the scr for my "roll your own cdi" is on its way, (got free quad coil from friend) . Will try to match base timing. 1 microF cap seems more aporopriate, but thats just the start of experimentation. Again "need a spare" is a good enough reason.

    I do like to go fast sometimes, but im not after revs (or should i say these engines arnt). Eventually ill at least rebuild with proper mounting hardware, some intake porting/matching, exhaust matching, exhaust porting?, bearings?, piston skirt trim, piston lightening? Then its a matter of selecting the appropriate drive ratio. I want 20 to 50kpm (14 to 31 mph) @ 2 to 5 thousand rpm not 45kph at 5500 rpm, screamin (cheaper to stick with this rpm and it seems to love it. Sounds gr8 too. Maybe a little more compression. Is compression only good for higher rpm???

    But for now i cant wait to try some lean mix fuel and some other jet sizes, but will have to wait due to studies being neglected because of this legal (not) chinese drug. Thanx for any sugestions. Sorry about the punctuation, it's soooooo hard on my tab. Sorry no pic, they are too high res for this site. Cheers'
     
    #7423 electron, Sep 14, 2014
    Last edited: Sep 14, 2014
  4. electron

    electron New Member

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    Pics in my album up!
     
  5. woogie_man

    woogie_man New Member

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    My intake tube fell apart, and drug my can through my chain. No damage to me or the bike, but a few small holes in the carb body and the intake. So guess I am out for the season, due to the cost weather and snow coming soon. That and I am.com liking at a new frame and doing some work on the engine so what better time than now.
     
  6. Cyclin

    Cyclin New Member

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    So I've been wrenching here and there the last couple weeks. New rear wheel + matching sprocket adapter so I have a spare. I hit 35 the other day which was cool. Recently I have been 4-stroking a lot at 25+ mph at full throttle. So I cleaned the carb, tightened the choke lever (which had gotten loosened due to 4-stroking vibes), and put on a new air filter, and drilled a vent hole in my gas cap. I also replaced the fuel line with a polyurethane one and added a new fuel filter. Still 4-stroking above 25mph so today I am going to check the toque on my head bolts, if that doesn't fix it I will try gapping my spark plug. If not that then I will replace the jet. I think I may have a pre-made spare hidden in my toolbox, but if I can't find it or it's the wrong size I'll just break out the solder and drill. Then for giggles I may as well re-seal where the carb meets the intake with some Permatex Ultra Black.

    I did some other stuff but I can't remember. Fixed a brake, bt there was something else... d*mn this awful memory. What I'd really love to do is install a jackshaft, like the SBP HD kit, but man, $200 feels like a lot for that kit.
     
    #7426 Cyclin, Sep 19, 2014
    Last edited: Sep 19, 2014
  7. electron

    electron New Member

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  8. electron

    electron New Member

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    After drilling the jet out to 0.8mm (no good) I had to fix this.
    I soldered up the jet and drilled two 0.5mm holes, which works out to about 0.7mm.
    Goes awesome now. Nearly no 4-stroking (prob need 0.65mm or so). Plug is dark grey instead of wet black. This is so critical, 50 times improvement!
     
  9. Rudz

    Rudz New Member

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    I want a re jet mine but it's not totally broken in yet.
     
  10. electron

    electron New Member

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    As long as you are using running in mix and you check for lean conditions, i don't see the problem with a more appropriate mixture. It runs nicer, even if you're still running in and less vibrations, smoother.
     
  11. Rudz

    Rudz New Member

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    Just checked, I have 180 on the odometer already, that was fast. I'm going to buy some Jets and lean her out


    I cut the tube out of the exhuast today, I didn't test it out though, maybe Monday, tomorrow is reserved for football
     
  12. mapbike

    mapbike Active Member

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    in my opinion the whole thing about a breakin period before jetting carb to run smooth without major 4 stroking is bunk....

    I jet mine to run good before I start my engines for the first time.

    Use a quality oil, mix it correctly and put some easy to moderate riding miles on it to get things wearing in nice and then ride it like you plan to ride it, if you ride it like you want to blow it up, most likely you will, but if you ride it within its confort zone your gonna be just fine uless youhave a lemon to begin with.

    Not the absolute gospel in every case, but this has been my experience with my engines.

    Peace, Map

    dnut
     
  13. electron

    electron New Member

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  14. Toothy

    Toothy New Member

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    Ouch! Hope you heal up fast.
     
  15. placidscene

    placidscene New Member

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    Well, it wasn't today, but the last time I rode my MB about 2 weeks ago, I went to an antique tractor show. I didn't get a lot of time to see the tractors because of all of the attention my bike was getting. That was fun.
    Only problem was, while I was explaining the bike to some of the oglers, I noticed a crack in the frame!.bf. I rode it VERY carefully home, and haven't had time to do anything yet since then.
    I am trying to decide if I want to start over with a new style frame (I like the board tracker style) or just simply repair mine, or modify mine (I would like to take the frame apart and give it a longer wheel base and a lower center of gravity).
    There is a Trek beach cruiser on Craigslist right now for $125. It looks pretty new. Hmmm. Decisions, decisions...
     
  16. Rudz

    Rudz New Member

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    Amazon has chromoly frames for sale cheap right now, problem is there is zero information on them. Idk what the bb size or headtube size is
     
  17. GearNut

    GearNut Active Member

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    Trek = very well built and strong. Just food for thought.
     
  18. Cyclin

    Cyclin New Member

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    Thanks for the tips guys. It was definitely the jet, jetted a little smaller and it ran much better until about 28-29 where it started 4-stroking again. Figured I still needed to jet down a little further this afternoon.

    But I never made it to this afternoon, near the end of that ride this morning my frame snapped. It was broken in 3 places, to the point where even my boss said to toss it. Otherwise he would have had our amazing welder fix her up for me, but this thing is toast :(

    So yep... that was my morning. Woke up still sick, w/ the added bonus of throwing an ear infection on top of the weekend's cold. Traffic light near my house was broken so I had to take an alternate route. Then my frame snapped and I had to push the beast the last leg of the commute, sick and miserable haha.

    But hey, got engaged on Saturday and the Mrs is extremely happy, so that's cool.

    Unless this was a sign.... dear god what have I done?!? Kidding... haha
     
  19. woogie_man

    woogie_man New Member

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    Got engaged....sick, ear infection, bike frame breaks.....yah I would run the other way..lol

    Already the frame didn't fail while you were going 30mph on her.
     
  20. mapbike

    mapbike Active Member

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    what kind of frame gave up the ghost on you?

    Just curious.

    Map
    dnut
     

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