My first kit and chain keeps breaking

Jhamlin said:

today i installed my first 2 stroke SD stinger motor on my hybrid schwinn crosscut. I works ok for a few then the chain broke...so i repaired it. It worked again for a few minutes then broke again. Again i repaired it. then i rode for a few more minutes and the chain blew apart. What the ****?

Is it that annoying chain tensioner?

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What size chain does your kit use, does it look like the same size as the bike chain or is it a larger chain?

Get you some of this and you wont be breaking chains anymore unless you have some serious mechanical issues going on with your bike but I doubt you would be busting chain unless it is the standard bike size chain.

you can fing the KMC415H chain a little cheaper at some places but most are only 98 links and that will probably be to short so go to the link I listed in this post and get the 122 link chain and then you can cut to fit on your bike and be done with the chain issue if all things mechanical are good on your bike.

http://www.1977mopeds.com/kmc-122-link-415h-chain.html

heres one on ebay that is at a very good price and its 120 links long

http://www.ebay.com/itm/KMC-Heavy-Duty-Chain-415H-/261281265942?hash=item3cd593b916&vxp=mtr

Hope this will help ya...

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I never rode a Stinger kit, but in general the china chains are garbage. Personally I prefer to ride a #41 industrial chain, you can get it at a good hardware store, farm and fleet, or order on Amazon.com etc. I got mine through Amazon from the AceHardware store on there. #41 chain is really solid, you wont break it....

As for the tensioner, I HATED it, after an experience very similar to yours I tossed the kit chain, tossed the tensioner and instelled the #41 chain straight from the motor to the rear sprocket, 2,500+ miles later and not a single problem with the chain! If you do ditch the tensioner I found the easiest way to find the right chain length is to shorten your cheapo chain till it fits without the tensioner (cause they are easier to break and mend), once you have the right length count the links and make a #41 chain with the same number of links. Not EVERY bike can be run without the tensioner, on some bikes the chain will hit the frame if run straight front to back. If you have a clear shot for the chain to run without the tensioner I would highly recomend it, the noise and resistance when pedaling is greatly reduced and so are chain failures.

420? Not sure, that could be the problem.. most kit chains are 41/410/415.

Is the chain breaking, or is it coming apart at the master link?

If the master link clip is the wrong way around, it will pop apart. As the chain runs into the motor, the bottom of the "U" should go in first.

Where exactly is it breaking? Can you post a pic?

Do you have chain slack? Are you running a tensioner? Does it ever skip teeth on either sprocket? Are you sure both sprockets are perfectly (or very close to) aligned?

Another vote here for the #41 chain, but it sounds like you have have one or more issue to sort out before tossing another chain on there.

check that those 420 links you bought are exactly like the chain you have, as most chains are 415 or smaller - 420 may bind in the housing for the drive sprocket

any chain that comes with the kit will work just fine if the rear sprocket is reasonably straight and the tensioner is adjusted at the chain's tightest spot in the rotation of the rear sprocket and also adjusted to feed the chain exactly onto the center of the rear sprocket

If there is a bit of wobble in the rear sprocket, you may want to grind or file the sides of the tips of the teeth to be very skinny to help them find the centers of the links

also, if the engine gets loose & starts leaning to the left, you'll have chain problems

SuedePflow said:

Where exactly is it breaking? Can you post a pic?

Do you have chain slack? Are you running a tensioner? Does it ever skip teeth on either sprocket? Are you sure both sprockets are perfectly (or very close to) aligned?

Another vote here for the #41 chain, but it sounds like you have have one or more issue to sort out before tossing another chain on there.

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Yah, I didn't mean to insinuate that running #41 chain (and no tensioner when possible) is a cure for poor chain alignment or sprocket assembly... It is very important that the rear sprocket is perfectly centered on the rear hub (doesn't bob up and down when spinning) and also side to side (doesn't wobble in and out). The tension is pretty important too, you don't want it too tight or too loose....

Jhamlin said:

the chain was bigger that a bike chain...at the store where i bought the replacement links the said it was a 420

so that means something is really wrong with the motor?

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Friend... I'm gonna say you have an alignment issue. and as for the 420 chain size, none of these engine kits come with that heavy of a chain, its 415 which looks the same basically and that is why it was mistaken for the 420 by that guy.

get you a new length of KMC415H chain and make sure the chian is properlt aligned and the sprocket on the wheel is mounted so that it run true, another words doesn't have a bunch of wobble side to side and also doesn't look like an eccentric because it isn't centered with the wheel, alignment is 99.9% of the problem people have with there chains, the kit chains are normally just fine for hundreds if not thousands of miles is aligned properly and lubricated, Venice at Venice Motorbikes has probably built a hundred or maybe more bikes and he uses the kit chains with excellent results as do many moreso I dont hate on them, they aren't as good quality as the KMC Chain or the #41 chain but these little engines dont put that much strain on the chain.....

Skyhawk kits run standard bicyccle chain and some people have good luck with even that and it is way weaker than the chain your kit came with so, take the time to make fro sure the the sprocket is in near perfect alignment with engine and the idler/tensioner roller is in alignment between the two, and that the sprocket is centered and true on your wheel, all of this is very important, your sprocket must be right on your wheel or you will have nothing but trouble.

CHECK THE ALIGNMENT... jhamlin you will likely find the problem there, 420 chain has larger pin size if I remember right so you dont need to be trying to mix match the stuff, just get you a KMC415H chain on the way and make sure all thing are lined up right and problem solved plain and simple........!

Best wishes and keep us posted on what you find and the fix.

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