First build

Discussion in 'Motorized Mountain Bikes and Road Bikes' started by bigwave, Dec 9, 2016.

  1. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    Howdy all, first build here, found an old MT bike at local bike shop for 20$ in good shape, a "free spirit", it's old enough that it has good bearings that are in holders (don't fall all over when repacking) and bike is pretty solid. My question is this, how critical is chain alignment? By the eyeball method it appears to me that my front engine sprocket and my rear sprocket are off by 1/8 to 3/16" (3-5mm) front to back. Can the chain length and chain tensioner handle that or am I asking for trouble? I can torque the engine a little to "point" the sprockets at each other, is that enough?

    Installing a "Flying horse" 66/80cc 2 stroke, silver (a few bearings or something) kit. I'm a shade tree mechanic that will work on anything, and pretty good at it, I service and fix all my own ATV's, work on Jeeps, etc. I'm no pro but understand most things mechanical.
    Thanks
     
  2. TheNecromancer13

    Joined:
    Jan 21, 2015
    Messages:
    592
    Likes Received:
    1
    Chain alignment is important. I found out the hard way that even if the chain alignment isn't off by enough to cause derailments, it will cause the chain to wear down your sprocket very fast. Are you using the stock sprocket adapter? If you use a hub or disc mounting sprocket adapter you can usually get perfect chain alignment with a bit of tinkering. Your spokes will also last a lot longer. Personally I like the disc sprocket adapters better, as they will fit any disc brake mount, whereas the hub ones only fit certain diameter hubs. Also with the disc adapters you can get longer bolts at the hardware store and use washers to space the sprocket out till you get good chain alignment. If that doesn't make sense tell me and I'll take a picture of one of my bikes so you can see what I mean.
     
  3. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    Kind of what I figured, thanks for the replay. Are you saying do not use the cheapo sandwich method that came with the kit? I'm having a bit of a hard time getting it to my satisfaction, I have flipped the sprocket around both ways and still not just right. One way it looks like the chain might hit the outer nubs on the tire and the other way it looks a little out of alignment from front driver sprocket to rear driven sprocket. I'll do a little search, what part are you saying to get, an upgraded sprocket hub of some type?
    Thanks
     
  4. TheNecromancer13

    Joined:
    Jan 21, 2015
    Messages:
    592
    Likes Received:
    1
  5. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    Also, where is best place to buy from, and which one do you recommend? Does this allow adjustment on the sprocket? I found a few and looked at them, it looks like you could use some spacers (washers) or ??? With this setup I assume you can just adjust the sprocket in or out by where you place it on rear wheel hub??
     
  6. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    I see what you sent, does this have the center split part that goes on the inside of the wheel over the hub? With out seeing how it attaches I'm a bit confused.


     
  7. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    I do not have a disk brake hub. I do not believe this model would work for me, what about one that goes over the center hub of rear wheel, one that is a 2 piece inner? Is there a universal one that would work with my existing sprocket, I don't want to dump a ton of $$$ in this until I know I like and enjoy.
     
  8. TheNecromancer13

    Joined:
    Jan 21, 2015
    Messages:
    592
    Likes Received:
    1
    If you want to use a hub adapter you will need to measure your hub diameter and get one that fits it. You will also need a wheel with 36 spokes. I would recommend getting a better sprocket to go along with the hub adapter. Many adapters will come with a sprocket. Here is an example of the type of thing you want: https://www.amazon.com/Manic-Mechanic-Sprocket-Assembly-1-003-1-008/dp/B00LGXTOVG

    Again you will need to measure your hub with a set of calipers to get an accurate enough measurement. Some hubs won't work with any of them.

    BTW, did you replace any of the parts that came with the kit, or is everything still stock? I ask because there are a few parts that you can replace for a few bucks that will make your ride much less likely to break down.
     
  9. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    First the parts, yes we did put in a "bolt" kit that had harder bolts, studs, etc. What else do you recommend. Please advise and give me a lists would be GREAT. I've fabricated a spring loaded chain tensioner, still work in progress but feeling much better than the "fixed one that came with it".

    As for the wheel hub, I may be hosed with this bike, it is conical on the outer edges, it's the same diameter in the center but only for about 30mm (1.2") or so. Yes it is a 36 spoke wheel and appears pretty true and solid. The rag adaptor went right on, I just don't care for that setup, but may give it a try.

    The rear wheel hub is kind of like this, but not that much, but you get the idea.
    \___/
     
  10. TheNecromancer13

    Joined:
    Jan 21, 2015
    Messages:
    592
    Likes Received:
    1
    In terms of cheap parts to replace, the fuel line is very low quality. Orchard or home depot have better fuel line. You already replaced all the bolts and studs, that is good, otherwise that would have been the first thing to do, cheap bolts caused me more problems with my first kit than anything else. The spark plug and spark plug boot usually fall apart pretty fast (my spark plug failed on the first test ride). A good replacement spark plug is the NGK B6HS. Any decent carbon core spark plug boot from the auto parts store will do. Chop one end of the boot off and unscrew the old one from the CDI, then screw on the new one in it's place. The fuel filter is made of cheap plastic and will crack easily and spill fuel everywhere. Use an in-line fuel filter meant for a lawnmower or the like. Throw away the fuel petcock, it is useless and doesn't actually do anything. Go to the hardware store with your gas tank and buy a barbed brass nipple to replace it with. You may have to re-tap the hole, as they usually have metric threads. Depending on what kit you ordered and what upgrades you plan to do, you might also consider replacing the chain. The chain quality varies wildly from kit to kit, I had a chain that broke pretty quickly. #420 chain is good. On some bikes it is possible to get rid of the chain tensioner entirely. If this is the case with your bike, you should do it. You may be able to use half links if the chain isn't the right length. On hub adapters, it sounds like your hub won't work, but I can't say for sure unless we get a picture and accurate measurement of the diameter. If you choose to try the rag joint, the wheel should last long enough for you to decide whether you like riding, but it probably won't last more than a hundred miles or so. If you replace the wheel, you can get a rear wheel with double walled rims, 36 triple laced spokes, and a disc hub for about a hundred bucks at performance bicycle. Then for another hundred or so you can get a nice disc adapter and a custom sprocket for 420 chain from rebelgears. I would recommend upgrading the sprocket because the stock one is cheap and I could literally bend mine with my hands, so I don't trust them. If you have a drill press (or if you're really patient and careful, you could probably get away with a handheld drill), you could also make your own disc adapter for a lot less, I can walk you through it if you want to go that route. In terms of more complex (expensive) upgrades, the first one is that your engine will probably 4 stroke from running too rich even at the leanest setting on the carb. To fix this you will need a smaller carb jet. The air filter is also rather ****ty and restrictive, a cone air filter would be a lot better. Also, if you want more power and speed, make yourself a good expansion chamber. A good one can easily double the torque of these engines, as the stock exhaust pipe is a piece of garbage which has the engine way choked down. If you want to see what I mean, try removing the end of the muffler and pulling out all the junk inside, then ride it around the block. It will be loud as ****, but you'll see a noticeable difference in power. Don't ride it this way though, you'll annoy people. A good expansion chamber will provide even more power than just removing the end of the pipe, and it will not be nearly as loud. You can also port the engine with a dremel without too much trouble. Hope this wall of text helps give you some good ideas.
     
  11. ultralight01

    ultralight01 New Member

    Joined:
    Oct 30, 2016
    Messages:
    338
    Likes Received:
    0
  12. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    I saw that one on EBay as well, looked pretty adaptable, I still think I'm SOL with my funny shaped rear hub, but I'm going to measure it at the widest point, I'm thinking I may be able to install a shim of some type to "even" it out if necessary.

    Just not getting a warm fuzzy, about this chain and sprocket setup (that came with it), as I've stated I've been working on 50+ HP ATV's for a long time and chain / sprocket quality and alignment are crucial to a good fun, reliable and safe time. I'm going to upgrade it somehow, just not sure which option at this time, I really like this bike I found, good quality bearings and sold as a rock (it's old) so I'd like to keep my rear wheel assemble if possible.

    Keep the ideas and comments coming!!!!

    I like and respect all input, experience is everything with projects like this. As I always tell my kids "You can learn more in 5 min from someone who already solved the problem, so listen"
     
    #12 bigwave, Dec 12, 2016
    Last edited: Dec 12, 2016
  13. TheNecromancer13

    Joined:
    Jan 21, 2015
    Messages:
    592
    Likes Received:
    1
    I'm not so sure about that hose clamp... if I was going to use a hub adapter, I'd get one with bolts that I can really torque down to make sure it doesn't go anywhere.
     
  14. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    " If you have a drill press (or if you're really patient and careful, you could probably get away with a handheld drill), you could also make your own disc adapter for a lot less, I can walk you through it if you want to go that route. "

    Disk adaptor plan, lay it on me, I have a drill press, a small welder, I'm extremely patient and tenacious when building and constructing. And I keep at least one fridge full of ICE COLD BARELY pops, that's a requirement when working on my jeep, mustang or ATV's dance1
    And my trusty Hounds "Vader and Capt. Rex" drn2, are always by my side. Not to mention it's 20 degrees and falling, outside, and I'm bored :-\
     
    #14 bigwave, Dec 13, 2016
    Last edited: Dec 13, 2016
  15. irishpowerjunkie

    Joined:
    Jan 24, 2012
    Messages:
    115
    Likes Received:
    0
    not entirely advisable but if you need a few mill try removing he outer set of metal plates that go behind the sprocket and it may get you what you need, as I say not advisable but may work for you, did for me and lasted around 300 miles (I was doing 150 miles a week at the time so was relatively short time to me) if you only plan on doing small miles at a time it may last surprising amount of time before it needs fixed.
     
  16. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    Rear sprocket / hub adaptor: I'm going to give it a try and see how it goes, I've got it pretty well lined up. I see a few other high dollar MT bikes I have hanging from the ceiling have a thicker, same size rear hub without the conical curves in the hub, I didn't want to use a $1200 bike for this project, but I might swap rear wheels around with one of them. Problem solved, and I can get the new rear sprocket / adaptor and spend 0 on a new rear wheel, we don't ride them much and the rear wheel on this one has a good set of bearings, 36 spokes, and seems solid.
     
  17. bigwave

    bigwave New Member

    Joined:
    Dec 9, 2016
    Messages:
    12
    Likes Received:
    0
    Whelp, she made the maiden voyage, took three tries and the removal of another link from the chain to get it to stay on. But, after that it stayed on for 2 laps around the hood, took a little work to get the idle right and the throttle cable adjusted but no problem there. All and all, I'd say a success. Running stihl chain-saw oil in it at 16:1 for break in; that's what I had in the cabinet. Why only two laps around the neighborhood?? Because it was 9-degress outside and I looked like Jim Carrey of "dumb and dumber" after just 2 laps!
     

Share This Page