Narrow sprocket and chain- Not recommended here

Discussion in 'Motorized Bicycle General Discussion' started by Nashville Kat, Jan 22, 2010.

  1. Nashville Kat

    Nashville Kat Active Member

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    As a former bike racer, I'm always concerned about the weight of the bike itself. Last summer I got a narrow motor sprocket and a narrow 410 BMX chain on ebay, and recently installed them on the new Schwinn Traveller build. Even the guy I got them from on ebay said he didn't recommend them and that they could be tricky, but as an experienced bike mechanic and with the lightweight Traveller going together I decided to try them on that.

    The weight difference didn't seem much when I had both chains in my hands, but I stilll thought I'd try the narrow, mostly then hoping to get a more natural pedal action with the motor off and clutch in.

    I got it together just before the cold snap and went outside to test, but the motor sprocket loosened up right away while I was trying to pedal start.

    So I just got it out again today. The allignment seemed perfect really, and I had put a half-link in the 410 chain so the tension seemed really good too. The motor turned over in several attempts, but just about the time I started t get it rolling, it threw the chain off, both front and back, and locked the wheel until I skidded to a stop- I still don't realy know why, but

    Glad I wasn't going any faster!

    Anyway, I'm going to put the kit sprocket and chain back on- the actual weight of the chain is not very much and the larger clearances give a much larger margin of error-

    I don't want to mess with something fussy, and I'm sorry I wasted my time even trying the narrow chain. If the kit manufacturers themselves have made the general switch these past few years, there must be a reason. I thought I might be able to get by with it, but my advice is:

    Don't spend any extra money, or time, on a narrow sprocket or chain.

    .bld.
     
  2. exavid

    exavid New Member

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    On my second test ride on my conversion the chain jumped and locked up the rear wheel. I was going quite slowly but making a U-turn in front of the house. It just happened too quickly to do much more than pick my butt back up from the street. Since then I modified the bike's frame so I could operate the chain directly without the idler pulley. Much easier to pedal and a good bit quieter.
     
  3. WayneC

    WayneC New Member

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    Hmmm. Did you just 'throw' the chain or did it break? I've been using BMX bicycle chain
    for a thousand or so miles and no breakage. I do run it with a different setup tho (CVT).
    And I use a spring loaded tensioner to keep it from bouncing around and I like the way it
    seats deep onto the sprockets. The 41 chain I started out with was alright but had a lot
    of side to side slop on the sprockets and would occasionally get thrown off of them. Strengthwise,
    BMX chain is holding up well.
    My 2 cents worth.
     
  4. troyboy

    troyboy Your East Coast Gasbike Connection

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    Some people who run 410' chains have made reports to have thousands of miles on them with no problems. I'm not arguing the point. The chain will stretch the most when it is brand new. Once stretched a final adjustment can be made to last some time. Proper alignment between the front and rear sprocket is essential to how your bike rides and your chain acts. I believe the 410 chain is great for the 48cc engine kits. They are Quieter and lighter for sure.

    The Grubee Kit in particular made the switch from the 415 to the 410 chain when the national supplier source changed from spooky to nationwide. I have the kits from both suppliers and spooks kit always had the 415 chains. I'm sure the only reason for the change was to save money on nationwides large orders. There are surely no extra benefits with a 410 chain on your motor side other then tire clearance.

    Smaller chains + smaller sprockets = less money. Multiply that by 1600 kits a month. Thats the only reason you now see the kits being offered with the #410 bike chains...
    They did used to say "upgraded #415 HD Chain"


    Justin
     
    #4 troyboy, Jan 23, 2010
    Last edited: Jan 23, 2010
  5. Nashville Kat

    Nashville Kat Active Member

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    It actually came off on both ends, so I'm not quite sure what happened. The lightweight minimal sprocket also got a little bent, but I think that was from the chain.

    I might play with the sprocket some more, but it may be too flimsy- its a 34 I got on ebey and bored and drilled, but now the arms may be compromised after bending. I may just put the nice offset 41 the kit came with first to see where the motor is with it- it's just a slant 49- so I'm wondering if it will pull the gear.

    iIm a little dissilusioned with the Traveler build- the tank barely has enough room to clear the stem and bars, so I'm plating with that- further back and it's in peddling way

    The chainstay clearances ARE tight, and that was one reason I went narrow.

    My cruiser now has one 27 inch wheel on the front and I thought I might eventually put one on the back- now I may have to use that wheel on this build. But I think a cruiser frame with the larger wheels may be what I'm looking for- a street machine that gets as much roll for the motor as it can-

    I think the longer wheelbase on the cruiser may be better than the ten speed, and the tank fits better.
     
  6. exavid

    exavid New Member

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    There's no doubt the motor will pull with a 41 tooth sprocket, that's lowering the gear ration a bit so there's more torque available at the wheel. I had a bit of chain stay clearance problem on my bike, the cure was to flatten the chain stay tube on the inside to give the chain more room. I welded a piece of steel on the outside of the crushed area to reinforce the tube but in aftersight it really didn't need to be reinforced. The good thing was I was able to do away with the idler pulley. So far I've put about 40 miles on the bike with no problem. Mileage will build up a bit slowly because there are two other bikes in the garage that need riding too.
     
  7. Maxvision

    Maxvision New Member

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    I put a shift kit on my bike and it came with a regular bicycle chain. The motor sprocket was too wide and wouldn't fit between the links of the chain. I used my belt sander and let the sprocket spin while I thinned it out to keep it all even. After thinning, the chain rollers fit all the way down in the valleys of the sprocket but the teeth were still a bit too high. 2 links would go on but the next roller wouldn't clear the top of the tooth. So I spun it again while grinding a little off the tops of the teeth. then beveled the top corners a bit. I works just fine now.
     
    #7 Maxvision, Jan 25, 2010
    Last edited: Jan 25, 2010

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