How to Solve Chain Stretch

Discussion in 'General Questions' started by flashstar, Nov 19, 2009.

  1. flashstar

    flashstar Member

    I am using the 415 chain that came with my Dax 70cc kit. I was planning to not use the tensioner until I realized that the chain was too long to go untensioned but too short to remove another 2 links. I reluctantly put the tensioner on and was surprised by the amount of stretching after 3/4 of a tank. I actually went through the tensioner adjustment completely and had to reposition the tensioner so that I could put more tension on the chain.

    Well, after 3/4 of a tank the chain has stretched enough to go without a tensioner. I removed the tensioner entirely and shortened the chain by 2 links and it's still a bit on the long side!

    Basically, this chain stretches worse than string cheese on a hot day. Should I look for some high quality 415 chain, 415h chain, or #41 chain? Can I use a 1/2 link? I've heard so many different answers so I'm trying to find the best solution. I don't mind ordering something online.

    I'm using the Tophat adapter, so the sprocket is completely true. I don't need the tensioner as a guide.

    Thanks
     

  2. 210061741

    210061741 Guest

    1st make sure the engine isn't tipping to the side.
    Sometimes they have a tendancy to do that.
    Put a L shaped bracket off the backside of the rear clutch cover botlt that is closest to the seatpost and brace it off of the seatpost.

    Then cut off some of the rear bracket at the square end where it contacts the motor or use thin shims like .032 inch thick cut to a tee shape to fit between the bracket and the motor and clear the studs. Leave a little hang out so you can grab it with vise grips so you can remove or position the shims.

    Get the chain tight but not over tight.
    You will trash the 6202 countershaft bearings or wear out your rear hub real fast.

    Toss that tensioner in the trash and use the .032 shims.
    1 shim will take up close to 1 link worth of slack.

    Yes the chain will still stretch but add in another shim and youre good.
     
  3. Al.Fisherman

    Al.Fisherman Active Member

  4. flashstar

    flashstar Member

    Thanks for the information. My engine is definitely leaning to the left. The bracket is a good idea, but I don't have any fabricating equipment. Would the right size L bracket from the hardware store work? I'll look at getting some shims. Also, is the 415 stock chain generally good enough?

    Thanks.
     
  5. Al.Fisherman

    Al.Fisherman Active Member

    Actually my bracket is a modified "L" bracket, store bought that I had laying around. Go get a "L" bracket and put it on temp. Once the bracket is mounted to the case you can rotate it to see where the arm needs to be cut to rest up on the tube. Since the bracket will rotate 360 degrees this is not a problem. The worse case as far as tools is to buy a hacksaw blade and wrap one end with tape or clamp in Vise Grips and cut off what you need to.
     
  6. On my Staton chain drive bike I replaced the chain with high quality chain from a local industrial supply store. 1/2 links work fine.
     
  7. AussieSteve

    AussieSteve Active Member

    Mine didn't stretch that fast. After 5 tanks, not much has changed. Mind you, early on, the tensioner bracket was moving a little, making constant roller adjustment necessary. I had insulation tape under the tensioner bracket - a no-no as I learned.
    Just a thought, though, check your rear axle nuts and make sure the wheel isn't pulling forward a little, loosening the chain. (Can't hurt to check)
    ... Steve
     
  8. Fabian

    Fabian Well-Known Member

    Hi Flashstar

    This is how you solve your 415 chain stretch issues - get a decent 415H o-ring chain.
     

    Attached Files:

  9. Hajuu

    Hajuu Member

    Yeah I also fell for the wheel slipping a bit and causing loss of tension..

    The drive from both sides of the axle really seems to drive the thing out unless its *really* secure.

    However with the hanger style axle bracket things on your bike its easy to just slide it evenly back or forward to account for the slack (usually). So I ended up setting my tensioner to max (which also formed the clearest angles as far as frame and tyre to chain was concerned), and then adjusting my wheel quickly with quick release nuts on the back tyre to account for the slack when neccisary.
     
  10. Hajuu

    Hajuu Member

    Yarr, I keep falling for posting on these old threads!
     
  11. Irish John

    Irish John Guest

    A good 415 chain from a motorbike shop is a good investment but the stock chains on Grubees are pretty good these days. I take out as many links as necessary when new to get the chain quite tight. Then after a good day of riding it stretches to about its maximum and I can normally shorten it a bit more which is then final. I like to get it so eventually it has a good line over the tensioner wheel which I ALWAYS keep low down on the slider so it can't suddenly slip down and cause enough slack for the chain to get sucked into the drive sprocket chamber and lock up as happens if the chain suddenly slackens for any reason. The attached picture shows a 2-stroke with chain how I like it. Not too tight and not too slack with minimum deflection over the tensioner wheel. I use hard steel bolts for the tensioner bracket so the threads don't strip but the stepped bolt on the tensioner wheel is a stock special and I can't replace that so I know it can't be tightened too hard without stripping so I keep it at its lowest setting for added safety. I slide the whole tensioner backwards or forwards along the chain stay to get the tension right and once set it is usually fairly permanent after the initial stretch of first 60 kms.
    When mounting the rear sprocket I take time to get it as true as possible but never get it so the chain is the same taughtness through one revolution of the 44 or 48T sprocket because no sprocket or chainring ever seems to be pefectly round.
     

    Attached Files:

  12. DaveinGR

    DaveinGR New Member

    I replaced my chain with #41 roller chain shortly after I built my bike. The stock #415 was a very inferior product and you can get 10 feet of #41 for about $15, problem solved! (for me anyways)
     
  13. AussieSteve

    AussieSteve Active Member

    Is 41 the same as 410?
    410 is too narrow for my countershaft sprocket teeth and won't seat properly.
     
  14. DaveinGR

    DaveinGR New Member

    #41 Chain

    #41 chain is different than #410, works great on my setup. Some body posted the spec comparison somewhere else on the site. It is widely available here in the states, I can get masterlinks, 1/2 links... It is much higher quality than the junk chain they send with the kit. What are you running on your bike if not #410?
     
  15. AussieSteve

    AussieSteve Active Member

    #410, as I understand it, is 1/2" pitch x 1/8" wide.
    What's different with #41? Is it (hopefully) slightly wider than 1/8", but narrower than 3/16"? ie 5/32"

    My kit came with 415H chain. I think it's 1/2" x 3/16" and is a little too wide, slopping around on the sprockets.
    #410 fits the jackshaft sprocket, only the countershaft sprocket is a problem.

    My countershaft sprocket won't take the #410 without grinding the edges of the teeth as mentioned - coming soon.
     
  16. Irish John

    Irish John Guest

    I used to have to replace every kit chain with a Yaban 415 motorbike chain which was the same pitch 410. They were $15 - $18 each back then but are now $40 so I don't buy them. The price rise occured same time as chains on Grubee kits improved. No chain fits some of those 2-stroke drive sprockets (especially ZBox) because they are machined so badly that no chain of any pitch would ever fit them. The variation in the sprocket is visible if you look carefullly at the attached photo. This one fitted no chain of any quality. Don't know about Grubee 2-strokes but I think their sprockets are machined in a better way. The ZBox ones were truly terrible. No sprockets or chainrings are perfectly round if they are made in China. The chain link lengths also used to be a bit variable as which will create problems as well.
    In the pic the dark chain is a Yaban and the light chain is a ZBOX - both 410.
     

    Attached Files:

  17. DaveinGR

    DaveinGR New Member

    #41 chain is 1/2" long X 1/4" wide. Works good on my set up but I am direct drive, no jackshaft. Looks like you're stuck with modifying your sprocket :(
     
  18. AussieSteve

    AussieSteve Active Member

    John, you said 'especially ZBox', implying that you got better sprockets from elsewhere.
    Where did you get the better ones? If I'm going to buy a new sprocket especially to grind the edges, I'd like to start with the best I can get here. (Might not even need to grind, then, to fit the #410.

    Does anyone know if a Grubee sprocket will slot straight on?
     
    Last edited: Mar 1, 2010
  19. Fabian

    Fabian Well-Known Member

  20. darwin

    darwin Well-Known Member

    Chains dont stretch they wear, cheap chains will wear the connecting links after only a short time because of shoddy craftsmanship ie. holes not being perfectly round and pins. After that breakin period you should be good to go until usual wear wears down the pins and elongates the holes.
     
Loading...