Chain Tensioner So about those spring tensioners...

Discussion in 'Transmission / Drivetrain' started by CarbonBikes, Sep 23, 2013.

  1. CarbonBikes

    CarbonBikes New Member

    Recently I've gotten into motorized bicycles and found out that a lot of people are having a problem with the shoddy tensioners that come with almost all kits. I've been trying a few new ones to see what's the best. The worst (besides the standard one) has been the spring-loaded tensioner I got from Bike Berry. Besides their products being over-priced, the tensioner exploded while riding @ 30 mph and destroyed my back wheel. It was a pretty crazy wipe out.

    Anyway, after a few words about that tensioner, I've tried to start recovering my bike from the incident. Other than a severed wheel frame, destroyed wheel, and a brand new tensioner that's broken (parts of which are still somewhere along the road :p), the bike's fine. I took my clutch housing off to change my chain (Oh, I failed to mention that was ruined as well?) after shortening the new chain with a grinder, I started to put my chain back on. Well, as soon as I go to put my clutch pin in it slides in all the way instead of sticking out a bit like it's supposed to. I took the opposing casing off (the one with the two gears) and found out that the little gear is now sticking all the way out. Not the screw, but the gear.

    So, long story short, how do I make the clutch pin fit the way it's supposed to? Did something else fall out (if it did, I can't find it)? And what's going on with that little gear.

    #Grubee Skyhawk GT5 66cc 2-stroke

    @BikeBerry ...thanks a bunch.
     

  2. Big Red

    Big Red Active Member

    Do you mean the crank gear is out too far? if so, is it hitting the case on the inside? Check to make sure the bearing is in behind the bucking bar, (clutch pin) hole. a bearing lives behind the short bar. and it is a very important part. it may have fallen out when the bar come out. it's just a pretty good size single bearing and easy to lose.
    Big Red.
     
  3. CarbonBikes

    CarbonBikes New Member

    @Big Red thanks for the reply. Is it a ball? Like it looks like a tiny metal marble? The crank gear is out too far, yes but I'm thinking it's not hitting the case. I'll check when I go back over. If it's a little ball then I'll just pop that back in. My pedal cranks got destroyed in the crash (failed to mention that too... oh well $$$$$ for a shoddy spring tensioner) and there's ball bearings everywhere. I thought it was just another one of those. But if it's not then I'll pop that in there. I'll google a picture of it unless you reply.

    Thanks again, and yes the crank gear is out too far.
     
  4. CarbonBikes

    CarbonBikes New Member

    So I got the clutch working again- the ball fell out so I put it back in. The gear is still sticking out. It doesn't seem to be causing any problems although I'd still like to find out wtf is going on with that.
     
  5. HeadSmess

    HeadSmess Well-Known Member

    ah, spring tensioners!

    the only good tensioner ive seen is on the camchain of an xr600! :jester:


    no., seriously... nasty pieces of bent steel! lucky you didnt get a cheap flying lesson at the same time like i have!

    erm... i normally cut the slotted section off, and weld it to the stay, it cant come off then!

    spring loaded has always been illogical to me...on the HT!

    you go to start them, and the chain loosens, falls off... you compression brake down a hill, chain loosens, falls off, jams in sprocket, wears hole in centre of tyre, bike falls over with operator semi attached...


    theyre ok on some types of drive.

    if they had a spring tensioner that LOCKED like most cam chain tensioners do... they only move one way, unless manually released with a tool of some type..



    if the gear is about 1/16 to an 1/8 out from the large clutch gear...thats pretty standard. they always poke out some.

    if that clutch gear had been made an extra 1/8 or so thicker, the things wouldnt make so much noise, either!
     
  6. briane

    briane New Member

    dont know about the clutch BUT...

    skip the tensioner - you dont need it unless the build is off. 5 washers on the axel to give a little room chanside, proper alignment, and you should have 1/2 a mm on each side of chain to spare.

    Its a tight fit.

    Why use something you dont need? check out my pics if you want to see how its done.
     
  7. CarbonBikes

    CarbonBikes New Member

    I want to start providing kits/bikes to people but I can't do it if I'm running around town with my bike falling apart because of those dang tensioners. I have a crazy idea I found in an industrial catalog for a tensioner, if it works I will definitely upload pics/vids of it. It's supposed to be the best way to tension a chain without mounting tools. Anyway, that's about as much as I'm going to disclose until I've tried it.

    Anyway, the tensioner is a huge problem because I don't want people riding around having to carry tools with them like I do. I've been riding for about a month now and haven't left without enough tools to completely repair the bike/engine if something goes wrong. It weighs me down a bit.
     
  8. Big Red

    Big Red Active Member

    PICS of the gear would help.And I ALWAYS CARRY TOOLS. May I suggest that you get a LOT more experence before you start building bikes for other people. A Motorized can kill you if something goes wrong.
    And what do you mean there's ball bearings everywhere? IF you don't know where all the bearings go then how do you expect to fix a customer bike?The tensioner has always been a PITA, BUT it works OK if installed properly.
    HEASDSMESS, yer SO SO RIGHT about spring tensioners, they just dont really work.
     
  9. CarbonBikes

    CarbonBikes New Member

    I said that my pedal crank got destroyed. There's ball bearings in the cranks..... That's exactly where I said they're from. I never said I don't know where they go, they go in the crank shaft for the pedals.
     
  10. Big Red

    Big Red Active Member

    Yeah bro, the bearing for the bucking bar is probably bigger than the crank bearings. Somehow I skipped over the pedal crank part, SORRY bro.NEED MORE COFFEE.
     
  11. CarbonBikes

    CarbonBikes New Member

  12. turbobuick1

    turbobuick1 New Member


    You guys should try my tensioner! Check it out:

    http://www.ebay.com/itm/49-66-80cc-...ain-Tensioner-Spring-Loaded-MMB-/181196082385

    IMG_0416.jpg
     
  13. butterbean

    butterbean Well-Known Member

    I bought a kit on ebay that converts the stock kit tensioner to spring loaded. Paid $20 for it, and haven't had any problems with it in 8 months.
     
  14. bigoilbob

    bigoilbob Member

    Kit looks good, but I don't need to lose more power to an idler. Admittedly not much, but I already lose in my gearbox, PTO to the alternator, and Nuvinci hub. I have a home made engine/gearbox/alternator mount with a motorcycle like tensioner. Works for me. An added benefit is the forced drive train inspection I must make while using it.
     
  15. butterbean

    butterbean Well-Known Member

    Well good for you buddy. I'm not going down another rabbit hole with you like I did with my battery gauge (which btw I added a switch to, and only turn it on before I start the bike or after I shut it off). The spring loaded kit works good for me and if there is any power loss caused by it, it's so negligible as to be unnoticed. Spring loaded is pretty much a necessity for me. I tried a static tensioner and the torque of the jackshaft throws the chain off it and pulls it towards the spokes.
     
  16. bigoilbob

    bigoilbob Member

    Touchy? Seems so. I had to look back to even remember what we "discussed".

    I'll tell you what I told one other on this forum. Go ahead and vent here, rather than taking it out on family over the holidays.
     
  17. butterbean

    butterbean Well-Known Member

    Yeah, you came into my thread criticizing me and then didn't even stick around to listen to me defend myself. So you wanna tunnel down rabbit holes, be my guest. I'll not follow. Poor forum etiquette.
     
  18. butterbean

    butterbean Well-Known Member

    Why do you engage people, then ignore them or act like what they have to say is unimportant? You're a first class d-bag.
     
  19. Racie35

    Racie35 Member

    Somewhere early on a lazy builder installed a chain tensioner rather than make an engine mounting with approximately 1/2" of adjustment which would just about do any link...soooo, since then everyone likes risking destroying a wheel and crashing. Its the dumbest thing on any build......cept maybe routing exhaust to your closed face helmet
     
  20. butterbean

    butterbean Well-Known Member

    People like you make me wanna smack the stupid outta somebody.
     
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