what did you do to your motorized bicycle today?

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

  1. crassius

    crassius Well-Known Member

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    getting an old junker I bought ready to go today - opened the carb to hook up cable

    this NT is so old that the slide is brass!!
     
  2. GearNut

    GearNut Active Member

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    Wow CCC, that looks really nice! What frame is that?
     
  3. culvercityclassic

    culvercityclassic Well-Known Member

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    The frame is a Richard Helmutt made frame. Limited production, comes with tank and tool box. One of the best frames I have seen and worked with.
     
  4. mapbike

    mapbike Active Member

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    Just curious to why the pedal sprocket is on the engine drive side, after looking at the pic for the second or third time that just stuck out to me for some reason.:confused:

    maybe I'm the dummy in the room on this but it just struck me as odd, but I'm sure its there at least for now for a reason.

    Map
    .wee.
     
  5. culvercityclassic

    culvercityclassic Well-Known Member

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    That sprocket is part of the jackshaft reduction drive system:
     

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    #6525 culvercityclassic, Nov 27, 2013
    Last edited: Nov 27, 2013
  6. mapbike

    mapbike Active Member

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    Ok great, thanks for the answer on that, I had thought of that because it did look like there might be a bearing on the back side of the sprocket but just didn't know for sure and figured it never hurts to ask.

    Thanks again and again thats gonna be a really nice bike..!

    Map
    reddd
     
  7. paintgun

    paintgun New Member

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  8. mapbike

    mapbike Active Member

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    Well, the verdict is in on an issue I was having with my latest build.

    I pulled off the newly made up expansion exhaust and put the home built pipe that has the large cylinder shape lawnmower muffler brazed to it and a 5/8" hole drilled through the diverter plate that is in center of muffler, I took my bike for a ride and GPS checked the top speed before removing the expansion pipe and I got a flat land top speed of 37.5mph and 40.0mph running down a small hill.

    After putting my old made up exhaust back on I,m @ 43.0 mph on the flat..... seems that the RT carb may have actually reduced my top speed by 2 mph on the flat compared to the NT carb I ran on the bike when it would scream up to 45 mph on the flat, I'm not changing back though because the RT dellorto clone is much more responsive and I can tell that most of the low to midrange gains I have seen were do to the RT carb and not the expansion pipe, there were low to mid gains with expansion exhaust but I can just barely tell any difference in acceleration and that difference is only on the low low end once I'm at around 20 mph it revs up about the same now and hit top speed quickly.

    I also pulled my clutch cover, removed the pucks and sprayed the pressure plate off good with carb cleaner and then took my pucks and sanded them down just enough to remove the glaze so they would grip good again, they had been slipping so bad I could hardly get the bike started but now they hold solid.

    Conclusion, I have lost top speed on my bikes every time I've put an expansion exhaust on them, probably due to the header pipe not being big enough (shrug), but I have found on my bikes that if I just make up a simple free flowing exhaust they do the best all the way around for mid and top speed power and rpms, I have one more expansion pipe that has a much larger inlet than what I've been toying with and I plan to make a 7/8" or 1" header pipe for it and try it on my Western Flyer build, if I don't get the results I'm looking for I'm probably done fooling with expansion chamber exhaust on my china girl engines, just not seeing any benefit to them on my bikes so far other than they are quieter and they help the basically stock engines in the low to midrange and are way better than the kit exhaust in there stock form, in my experiments so far I have lost top speed on every expansion pipe set up I've used on my bikes but I'm hoping I can get one together next time that I'll be happy with, if not then I'll just build what I know works the best for me and throw the expansion pipes in the junk pile.....lol!

    Next mod on the Moon Doggie bike is gonna be a 32T rear sprocket, seems I have plenty of power to pull it and that will get me at 40mph cruise at lower rpms.

    By the way, the SBP expansion exhaust is excellent on stock to mildly modified engines, low mid and upper power are increased over what the stock pipe will allow the engine to do, I still run the SBP exhaust on my Karaoke Huffy and I'm satisfied with it on that engine because it is so unbalanced that at 32-34 mph that is as fast as it is comfortable to ride and the pipe lets it breathe great from start up all the way up to that speed, just wanted to add this part because for stock to slightly modified engines and those looking to cruise in the 35 +or- MPH range the SBP pipe works great.

    Map
    reddd
     
    #6528 mapbike, Nov 27, 2013
    Last edited: Nov 27, 2013
  9. Huffydavidson

    Huffydavidson STREETRACER/MANUFACTURER

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    Just now finished swaping motors back to blue ready to run but it to late to start the bike in the apt.laff So still being all HOPPED-UP on coffie I'm starting to work on the
    "LaJolla Davidson" build. With the Fred motor.
     
  10. mapbike

    mapbike Active Member

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    Have you decided to put the Fred Motor on the LaJolla Bike?

    Or did I read this wrong.

    Map
     
  11. MEASURE TWICE

    MEASURE TWICE Active Member

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    Since I replaced a set up pulleys with gears and chain that were part of a very low ratio for good torque up hill climbing, I no longer have that smallest 1.7 inch diameter pulley slipping.

    I just got a large 28 tooth gear I ordered and intend to use it with an 18 tooth or a 13 tooth gear. This will get me back my low ratios of around 20:1 and 30:1 ratio.

    Temporarily I only have two 18 tooth gears in place so that with two other belts and twin jackshafts gets 14:1 ratio.

    I would really like to see it climb without needing as much run up speed when trail riding.

    The smooth trail with slight grade in the photo is not the majority of what there is there to ride. I'll be back with better torque and using the sweet spot of the 3hp Briggs 4 stroke's power band next time out.

    MT

    http://motorbicycling.com/showthread.php?p=527975#post527975 (the rough stuff trail riding)
     

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    #6531 MEASURE TWICE, Nov 28, 2013
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  12. Cruise

    Cruise New Member

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    Ready to now put some mileage on my new chopper, so put some road lights, speedo and mirror on it. Also fitted front fender with some gentle persuasion.
    Nearly done running in. Still got a slight vibration issue but all else seems to be behaving.
    Very comfy ride.
     
  13. BonusParts

    BonusParts Member

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    [​IMG]
     

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  14. mapbike

    mapbike Active Member

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    Nice pic...... 39mph is a nice cruise speed.

    Is your bike a shifter bike or a single speedster?

    I also like that speedometer you have, needing a new one myself.

    Map
     
  15. paintgun

    paintgun New Member

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    Nice speedo. Gonna get one of those dual-pull brake levers. How well do they work?
     
  16. Huffydavidson

    Huffydavidson STREETRACER/MANUFACTURER

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    They work very well. I love mine. Disc in front and V brakes in the rear on a dime.
    Almost done with the LaJolla Race bike. Its 5am almost to get back to work on it.
    I'll just close my eyes for a min.
     
  17. paintgun

    paintgun New Member

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    Thank, Huff. I called the local bicycle shop yesterday and asked if they carried them. The guy told me he had never heard of such a thing. He didn't sound like he was the shiniest tool in the shed either. So go figure. Probably just get one off either ebay or SBP.
     
  18. BonusParts

    BonusParts Member

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    single. 36t. shifters are for the weak of heart

    supremely well for v brakes
     
  19. paul

    paul Active Member

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    I know I really liked my dual brake lever when I had them on my motorized bicycle.
     
  20. Southgate Jonny

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    Installed a balanced lower w/a fresh 69cc top end and slant head (all Dax stuff). Made up an Opti 2 premix @ 80-1 (too esceered to go 100-1 for the break-in). Warmed her up and took off like a Scud! SMOOOOOOOOOOTH! Got up to about 27-30 mph @ a bit over 3/4 throttle but didn't want to take her any higher for now. Thing's gonna be a monster when she gets broken in!
     

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