Chain Tensioner Chain Tensioner, Fuel Mix, and Other Questions

Discussion in 'Transmission / Drivetrain' started by Asz, Sep 25, 2007.

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  1. Asz

    Asz Guest

    Hi guys. I recently had a little accident with my bike when I improperly mounted something to the rear rack I installed which caused a lovely broken spoke on my rear wheel. After realizing that the couple places I tried to take my wheel to in order to have the spoke replaced refused to service motorized bikes I hunkered down, bought a bunch of necessary tools, and did the job myself. All of this took a little over a week, due to work, lack of proper tools and other things, with me just finishing up a couple hours ago.

    Now the first question I have, and it may sound a bit odd: Can fuel evaporate from inside the tank? I recall having around 1/4 or 1/5 of my fuel tank full after I broke the spoke, when I went to ride it after fixing the problem I noticed that my fuel tank was empty! It either evaporated, or the one other person in my apartment complex with a bike (full sized dirt-bike, which I'm guessing takes two-stroke?) syphoned the remaining fuel out of my tank sometime during the week.

    Second question: I had just a 1/4 or 1/5 tank left of fuel before I was done with my break-in period on my bike, so while mixing up the next batch of fuel I decided to go ahead and run 32:1 as I've seen noted by various people around here on the forum. It may well be the fact that I haven't rode my bike around in a week but I noticed that riding the bike isn't as smooth as I remember it being, could this be because of the lower fuel mixture?

    Third question: While putting the chain tensioner back on I noticed an awful lot of slack at the lowest position of the wheel so I raised it up to the point where there is only around 1 to 1-1/3 inches of slack in the chain. Even still, the chain when in motion seems to have barely a few millimeters of clearance between the top and bottom portions. Should I drop the tensioner lower? Highten it? Could this be why the ride wasn't quite as smooth as I remember it?

    Last question: How much side to side movement should the tensioner wheel have? I noticed when I put it back on that there was maybe 1/3" of side to side movement in the wheel. Should it have this side to side slack? Could I have forgotten a bit when replacing the tensioner?

    Thanks for your help guys!

  2. mickey

    mickey Guest

    If your tensioner is similar to mine, the axel bolt is shaved at the threaded end to fit into the slot of the bracket. If you didn't get it aligned into the slot, you will have extra side to side play.
  3. mickey

    mickey Guest

    Also, if your top and bottom chain runs are getting too close together for your comfort, remove a link from the chain and reposition your tensioner appropriately.

    My gas seems to evaporate at times as well. Whether this is common or not, I don't know. Ive never lost as much gas as you though.
  4. Asz

    Asz Guest

    Thanks for the tip! I noticed the shaved part earlier when I was putting the tensioner back on but just kind of stared at it blankly with no idea why it was like that. After repositioning the tensioner with the shaved bit in place theres no more side to side play. :)

    I also went ahead and moved the tensioner wheel up a wee bit more (now theres around only 1" on play in the chain) and the top and bottom sections of the chain are clearing each other with pretty adequate room. Should I worry about this being over-tense and snapping or wearing down the chain faster?
  5. azbill

    azbill Active Member

    with a new chain ... less than 1/2" deflection is best
    it will stretch and get looser, so if you start really loose, it might fall off
    (happened to me :p)
  6. Scottm

    Scottm Guest

    I got mine too loose and it bunched up inside the cover where the motor sprocket is.
  7. thatsdax

    thatsdax Guest

    Keep it tight for.........

    When brand new... Keep the chain snug for the first 5 or 10 miles.. Key is...Keep it snug for the first few miles. Once the chain and sprockets adjust to each other in the first few miles, you will see that there will be a lot of slack. Do not let too much slack get into the chain. But you need a little play after it breaks in. Typically 10 miles or so. Enjoy the ride..
  8. davidsis

    davidsis Guest

    Chain question already answered. The engine that I bought from thats Dax, was kind of rough untill I ran about two gallons of gas through it. Mine is a 80cc engine that mounts on the center tube over the cranks. I also got a different spark plug Champion cj7y. with gap .020 Runs real good now I use 32:1 ratio Penzoil semi synthetic, but during break in I used regular Valvoline from autozone. multi use 2 stroke oil. for chain saws weed wackers leaf blowers. Oh ya I also got a different spark plug wire from autozone 8mm
  9. nhman

    nhman Guest

    I'm glad to see others having questions about fuel evaporation (misery loves company?) I thought I was cracking up. Guess I'm STILL sane, which means I have to behave "responsibly" today...........again!!
  10. Scottm

    Scottm Guest

    Me too. I often find streaks of fuel running across the top of my fuel tank and the bottom of the cap is always wet. I kow my tank was full the other day, got over the top of a hill and down to the bottom of the otherside and the bike shut off. Tank was dry as a bone. Had to pedal back up hill. You kow I'll check now everytime before I get on. It's still hot here and I know it gets about 110 in my garage since the door faces east. I don't wonder if the heat causes it to evaporate onto the gas cap and then run down the sides of the tank.
  11. Asz

    Asz Guest

    Adjusting the tensioner wheel into place correctly and running my bike for 5-10miles with the 32:1 mix helped to fix any weirdness I was feeling earlier. I also did the "silence" trick using some heater hose and its a wee bit quieter on the high pitched noises now too. Looking to install my boost bottle tomorrow as well! Thanks for your help guys, though I am still a little confused about the whole fuel evaporation. It does get kind of annoying having to wipe down the tank every day due to streaks of fuel evaporatin and running down the sides.
  12. thatsdax

    thatsdax Guest

    You may need a new......

    If you have fuel sweating at your tank filler neck, it may be that you need a newer style fuel cap. Look at yours.. Is your gas cap sawed off and short? or is it the newer longer style cap ? Take a look and see. Enjoy the ride..
  13. Asz

    Asz Guest

    My gas cap doesn't appear to be sawed short. Would a different cap make any difference? I've noticed that th sweating only happens when my bike is sitting around in the boiling Tucson sun. Not exactly the most surprising circumstances. :)
  14. azbill

    azbill Active Member

    sounds like it's just vapor condensing after it escapes
    I have same problem