Chain Alignment issues. Chain keeps breaking.

Which Chain is better for my 80cc motorized bike?

  • 415 Heavy Duty Chain

    Votes: 2 33.3%
  • #41 Chain

    Votes: 4 66.7%
  • Other

    Votes: 0 0.0%

  • Total voters


New Member
Mar 1, 2018
I have the Aurelio Tech 80cc 2-stroke motor kit for my mountain bike. Everything has been just fine except for the chain. Originally I had the tensioner way too tight and of course the chain snapped. Luckily it just broke the master link.

So I ordered a Chain Link Remover and fixed it. Readjusted the tensioner so there was a little slack, but not too much. Everything has been great for the last 2 days of riding.

Today on my way to work out of no where it just snapped. When I checked my bike after the most recent chain break I noticed it was chewed up in multiple areas and appeared twisted. It had loose links that seemed like it was going to fall apart. I did my best using the chain link remover to fix all of the problem links, but wasn't successful. There is no way this is going to go back on..

So I ordered a new 415 Heavy Duty Chain for my bike since this is the one that was originally on it. Now I was browsing some other threads and noticed people are getting #41 chain from tractor supply shops. Are these much stronger? If so, is this something I should invest in?

I also ordered a spring loaded tensioner that attaches to the top arm on the back wheel. Hopefully after I replace the chain and add the new tensioner it will work just fine.

My main question here is: What tips and tricks can you guys give me for when I'm trying to align my chain from the motor to the sprocket? Is there something I can use to make sure its even? The slack part is no longer my issue. I believe my main issues is with the chain alignment not being totally right.

Below is the link to the tensioner I ordered as well as the chain I ordered.




May 25, 2008
Just a thunk. But when you put the chain on, be sure the sprocket is centered. Off center will cause "loose, loose. Tight, tight, to tight..." as you walk it to check.

I've used really bad, cheap chains and heavy duty, "good" ones and both will work but off center and ya kill either.

Does sound like your original chain was over stressed.


Mar 1, 2018
Getting that rear sprocket aligned is probably the number one issue iv had with these bikes. The stock chain tensioner is so bad I would recommend since you have a chain breaker to cut the chain to the right length and throw away the chain tensioner. Or if your having problems getting the rear sprocket aligned with the stock pinnaple adapter to get an aftermarket sprocket adapter. There are cheap ones on ebay that will make getting the rear sprocket true much easier and are a lot stronger


Well-Known Member
Dec 31, 2014
Dan's comment is dead on. Using a spring loaded tensioner will help with some mis-alignment of the rear wheel, but isn't an excuse for not aligning the axle properly to begin with. If you can't get the wheel to run true then I would check for a bent axle or bent or loose/overtightened spokes, all will prevent the rear wheel from coming into alignment.

Once the wheel is running true I always check for a straight chain line, when motor sprocket and rear sprocket are perfectly straight it takes lateral pressure off the chain as well. An angled relationship of sprockets front to rear is tantamont to "cross chaining" (running inside and outside chain rings of front & rear derailliers at the same time) of the pedal side drive on a multi-speed bicycle & an angled chain should be avoided on the motor drive chain line as well.

Proper chain tension is a dynamic factor & testing for that 1/2" deflection should be checked by advancing the rear wheel to 5 or 6 different locations & checking chain tension at each. A properly setup drive line should not vary significantly during this test. Also once you have the spring loaded tensioner in place, just watch the action of the tension arm. It should move dramatically if the rear wheel is aligned properly.

Finally check the chain stay, seat stay & rear axle drops. If any of these are bent or damaged the rear axle won't align properly. This last is a worst possible case, but on even a new bike damage could occur during shipping.
Rick C.


Well-Known Member
Sep 30, 2012
one important thing not mentioned above is that once a chain has broken, it must be CAREFULLY inspected to see if any links are twisted or loose - if in doubt, get a new chain