A tensioner with style and functionality

Discussion in 'Photos & Bicycle Builds' started by David Bogle, Mar 27, 2016.

  1. David Bogle

    David Bogle Member

    Hello from Lansing Michigan,
    This is a tensioner that I made for my very first MB build, I wanted nice tensioner on a low budget, solid and beautiful, I finally got to use my degrees in art. I added an led light to add to the appeal. IMG_20160327_195708.jpg IMG_20160327_195708.jpg IMG_20160327_194616.jpg IMG_20160327_195708.jpg IMG_20160327_194616.jpg
     

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    Skull and cross bones, eh? Pretty cool.
     
  3. David Bogle

    David Bogle Member

    I had to find a shape that would lend itself to the task, then it dawned on me that the crossbones would not only hinge down but also work great with the skateboard wheel from there the design fell into place. Do you think it would sell?
     
  4. KCvale

    KCvale Motorized Bicycle Vendor

    Very creative, and that blue back light was clever.

    Sure a couple a year anyway.

    The problem I see with that design, is needing to take the whole tensioner off to get to the engine covers.
    How is mounted?
     
  5. David Bogle

    David Bogle Member

    It's mounted by the bolts that appear as horns, they also are the bolts that hold that cover so it's really no extra work to get to the sprocket behind it , I did think about that in advance so it's no problem.
     
  6. KCvale

    KCvale Motorized Bicycle Vendor

    Cool!
    If you need to get to the back cover you have to take them out anyway.

    What concerns me is using skinny cover size bolts to hold up a piece of steel and be a chain tensioner too.
     
  7. David Bogle

    David Bogle Member

    I don't remember them being all that "skinny", I always replace all the bolts and with a better quality maybe that's why I wasn't concerned at all, my only concern was how sharp I made the horns, I had some painful scratches by fall.
     
  8. KCvale

    KCvale Motorized Bicycle Vendor

    Heheheh...

    Probably not as bad as riding something these these..
    [​IMG]

    [​IMG]

    Anyway cool and I wish you luck.
     
  9. JunkyardDog

    JunkyardDog Active Member

    Not to crazy about the look, there are skulls everywhere now, and I'm not sure why. But we do need a quality failure proof tensioner, one several times stronger than what is absolutely necessary, and that does not clamp onto any part of the bikes frame. Ideally the bike frame would have a super heavy duty steel mount welded on, and the tensioner would bolt to that. It would need to be adjustable, like a derailleur, so it could be lined up perfectly with the chain. And it would need to be under constant spring tension, so it would move with the tight and loose spots in the chain, keeping constant tension on it. I would like to see a steel sprocket, that fit the chain, running on high quality bearings. The basic design of a derailleur would seem close to what is needed, just bigger and much stronger, for the motor driven chain. Such a device is certainly possible, most would object to it's cost, but having almost been killed by one of those Chinese POS things (crashed inches from 45 mph traffic) I would not. Motorized bikes have long needed much higher quality components. Parts that fit without cutting and drilling and shimming, basically rigging things to try and make them fit the bike. I don't know of any statistics on the matter, but I have to wonder how many people have been killed or seriously injured when they rigged a Chinese engine kit to a Walmart bike with cheap wheels and only a rear coaster brake.
     
  10. David Bogle

    David Bogle Member

    IMG_20160403_093106.jpg
    [/SIZE]

    Sorry you're not crazy about the look, other than that it seems to be everything you're describing in your rant, stronger than necessary( do you see the size of that spring?) High quality bearings ( have you ever priced skateboard bearings?) With the skateboard wheel being 1.5" in depth it lines up perfectly with the chain is under constant tension with no cutting drilling or shimming needed, similar to a derailleur and doesn't hook to the frame, but if it's the skull that you really have a problem with you're not alone, my wife said that it wasn't for her either so maybe you'll like this design better,
     
  11. JunkyardDog

    JunkyardDog Active Member

    No, not to crazy about that one either. I'm the mechanical type, and like mechanical parts to look like mechanical parts. I have never really been one for decoration. As for the rest of it, it is hard to really get a good look at it from your pictures. I did not know you used a skateboard wheel. You didn't say so, and it isn't obvious from the picture. Actually a skateboard wheel sounds like a pretty good idea for a tensioner roller. Certainly a lot better than what comes in those kits. I have a lot of issues with those. One, they are way too flimsy for the job they are meant to do. Both the bracket and the roller. They mount to the bike in a way that allows them to rotate on the frame. Mine was very tight, yet it still wound up in the rear wheel spokes, breaking several spokes and locking up the wheel, and dumping me on the road in front of oncoming traffic. Also, while they are adjustable, they are not spring loaded and they cannot pivot to maintain constant tension on the chain. You seem to have solved many of those problems. I'm not putting down what you did. But you had to build it. What I would like to see is a well made commercially available part. As an auto mechanic, I like precision. A derailleur is a precision made component, And I just think that something of similar design but bigger and stronger would be just what we need. But I guess it really doesn't need to be that complex. Just overbuilt for what it needs to do, and attach solidly to the bike without clamping around a frame tube.

    I have so many issues with these Chinese kits. I know they are cheap, and people like that. But they never fit properly, the tensioner and method of attaching the sprocket to the rear wheel is terrible, The engine and gas tank mountings almost always have to be rigged. I'm not saying that I think all this should go away, other than the tensioner, which is downright dangerous. But I would like to see motorized bikes come out of the stone age. I would like to see a company build upscale kits, including a frame and rear wheel specifically designed as motorized bike parts, so that everything fits. A motorized bike is such a cool idea, both as transportation and fun, that can be ridden in most places without all the red tape hassles of a motorcycle. I think they deserve better than what we have today. I'm also on the 4 stroke bandwagon, and am using a Honda GX35 with a friction drive. I would love to use that same engine, only frame mounted, with a shift kit. A shift kit eliminates many of the problems with the Chinese kits. But there are still usually engine mounting problems. Many are caused by the way bicycles are built today. Whatever happened to bicycles built with small diameter round steel tubes? All the tapered and oval shaped frame tubing certainly complicates mounting things. But again, a frame designed for a motor, with welded on mounts for everything (engine, gas tank, and tensioner) would solve a lot of problems, and would be so simple to build. Ultimately I would like to see complete factory made motorized bikes, made to high quality standards, just like real mopeds were back in the '70s. A motorized bike would solve so many of the issues mopeds had. They would not require registration, insurance, motorcycle license, etc. and the most important part, they can be ridden in bike lanes where mopeds can't. They are perfect for someone like me, who loves to ride a bicycle, but are physically unable to pedal anymore. They can be parked at bike racks (if you want to take the chance, I had one stolen) and they could still be customized by the owner. Sorry about this "rant" but I am very passionate about this. I am a lifelong cyclist, and perfectionist, who is no longer physically able to ride a pedal bicycle. And I can see no technical obstacles to building a high quality motorized bike. I think it would be nice to see someone like Honda, with all their engineering expertise, build one.
     
  12. Timbone

    Timbone Active Member

    A good tensioner can be made any number of ways. Roller skate wheel would great mounted on a 3/8" axle. I use hard plastic washers that roll freely on a 3/8" clevis.

    Using a 415 chain or heavier, one could fashion a piece of mild steel. With a touch of grease, the side plates would quickly eat into the mild steel and once you are down to the rollers the chain would slide smoothly by with very little resistance. Spring based tensioners look cool but they are not the best way to roll.
     
  13. David Bogle

    David Bogle Member

    I guess part of what I'd like to convey is that not all of us were born with a silver spoon, or lucked out and got a great pension , if the market doesn't have what you want or just can't afford it, you can always build your own,
    As for Chinese kits, I've Never had an issue with the fit, sure sometimes you may need to pick up an angle grinder or a drill, face it,
    If you can't overcome an oversized tube then the alternative is buying a scooter, it seems that's what you've described. Everything all nice and neat ready to buy off the shelf with everything pre engineered with all the high tech welded and powder coated bells and whistles.
     
    Last edited: Apr 3, 2016
  14. Timbone

    Timbone Active Member

    The stock kit is workable. The motors are dependable and want to run. The rag joint is fine and, when properly attached ( with locknuts) to a true wheel with tight spokes, will provide several thousands of miles of good service. The stock CDI is nicely insulated and will perform dependably for a long time. Get an NGK spark plug. The 415 chain is bombproof. The Sprockets are good quality. The clutch is simple and easily adjustable, lasting a long time.

    What won't work? The stock motor mounts. Not nearly beefy enough. Attach the engine using big metal. The NT carb. The needle slide is just too simple and even with the right jet it will frustrate you. Get a dellorto clone for about $30. The stock tensioner is too frail but the support bracket is fine. Affix a 3/8" axle into the bracket and use heavy nylon washers as the contact surface. You can surround these washers with 2" steel fender washers. Tighten the bracket like crazy and use blue Loctite.

    The magnetos will fail so it's always good to have an extra on hand. Keep an extra CDI around, too.
     
    Last edited: Apr 3, 2016
    David Bogle likes this.
  15. David Bogle

    David Bogle Member

    Can anyone tell me what happens if you remove the tensioner all together,
    And set the tension with the rear tire the same way the peddle chain is adjusted.
    I believe I know what you will say, the 415 kinks up around the drive sprocket.
     
  16. Timbone

    Timbone Active Member

    There are many good mechanics on here who will tell you that this is the way to do it, by optimizing chain length by placing the rear axle so that no tensioner is needed on the motor chain. I tried that method and it did not work for me. But many do that and they find success with that method.
     
  17. JunkyardDog

    JunkyardDog Active Member

    So what if it coast $1200 or $1500 for a quality motorized bicycle. That is not really a lot of money anymore. And it could last a long time, probably over 10 years. It would not be for everybody, but I think someone should make such a bike, or the parts to build it. Look at the late Taiwan made Whizzer. To bad it's engine displacement made it illegal as a motorized bicycle in my state, and it was not DOT and EPA approved so it could not be registered as a moped or motorcycle. I have a Taiwanese made scooter, an SYM HD200 (actually 163cc) it is registered as a motorcycle. But it is big and heavy and awkward compared to a bicycle.

    You CAN buy factory made electric bicycles. I actually rode a Pedego. Excellent engineering and build quality, but for the range I wanted, nearly $3500. You could build a gas powered bike for a third of that, with unlimited range. The main thing is that it be 48cc, and look exactly like a bicycle, not a scooter or a moped. You should be able to pick it up and carry it around. It should have bicycle wheels and fully functional pedals, not like a moped. Ever try to pedal a moped?

    This is a Puch moped I used to own. I would have worked fine for me except for one thing. It was not legal in the bike lanes, which made it a suicide machine in traffic. You can't ride a bike that slow in traffic. You have to ride to the far right, bicycle lane or not. A motorized bicycle IS legal in bike lanes, and that makes all the difference.

    [​IMG]
     
  18. David Bogle

    David Bogle Member

    But anyways, back to the subject of the tensioner, does anyone have pics or descriptions of a tensioner that they have made ,bought or seen that they feel works better than the standard kit tensioner?
    (I honestly have no issue with the kit tensioner, you just need to drill a hole through it and the frame to bolt it in place).
     
  19. JunkyardDog

    JunkyardDog Active Member

    David Bogle likes this.
  20. David Bogle

    David Bogle Member

    I like this one, basically the same concept as the ones that I built but light weight and with a sprocket and a hefty price I'm sure junkyard dog will approve as well including the price ,myself I think I would rather copy the design (not difficult at all) I would prefer a steel sprocket but overall looks like it would work well.
     
Loading...