Chain Broke, Any Advice?

[FatherMoonMan]

Hey yall, i was hoping yall could point me in the right direction as to why my chain keeps breaking. I have about 190km on the bike and the chain just broke out of nowhere. The last time I rode was a week or two back, and it was completely fine for over 3 hours of redlining, and then yesterday it came off really slow speed (around 15 km/h) 10 minutes into my ride.

The chain got twisted up and one of the links bent 90 degrees. This is the first time the chain has broken on this bike but on my old bike that had nonstop issues (bought it off someone for 50 bucks to wasn't expecting much) that chain was a constant problem, needing to be replaced every 50-100km and part of the reason i built this new bike with better parts.

It was a #41 chain being tensioned by a spring tensioner instead of that wheel thing that comes with the kit and an 80cc motor with a HP carb if that makes any difference. I would prefer if i didnt have to buy a new chain every 200km so any tips or advice is appreciated.

 

[YetiWoodz]

When I first built my bike, my chain kept breaking because the sprocket wasn't flat, so it was turning crooked. That needed to be hammered flat.

Also there were burrs that needed to be filed off in the center hole so it fit on the adapter correctly.

Proper chain tension is important too. Too loose or too tight and it'll break.

 

[DAMIEN1307]

why my chain keeps breaking.

I would venture to guess that something is not aligned properly...The rear wheel, of course needs to be running straight and "true", meaning no visible wobble side to side movement etc, and check that the bearing in the rear wheel when holding the tire and trying to manipulate it it sided to side should also show no movement.

Does the rear sprocket, when spinning the wheel show any warpage at all...if so, the rag joint holding it to the wheel is not correct...there should be no more than a 16th of an inch of play in that sprocket so as not to be twisting/stressing the chain.

Well, thats a good starting point for you to start looking...lol...DAMIEN

 

[Chainlube]

Hey yall, i was hoping yall could point me in the right direction as to why my chain keeps breaking. I have about 190km on the bike and the chain just broke out of nowhere. The last time I rode was a week or two back, and it was completely fine for over 3 hours of redlining, and then yesterday it came off really slow speed (around 15 km/h) 10 minutes into my ride.

The chain got twisted up and one of the links bent 90 degrees. This is the first time the chain has broken on this bike but on my old bike that had nonstop issues (bought it off someone for 50 bucks to wasn't expecting much) that chain was a constant problem, needing to be replaced every 50-100km and part of the reason i built this new bike with better parts.

It was a #41 chain being tensioned by a spring tensioner instead of that wheel thing that comes with the kit and an 80cc motor with a HP carb if that makes any difference. I would prefer if i didnt have to buy a new chain every 200km so any tips or advice is appreciated.

Got any pictures of your bike? Certain alignment issues will where down a chain, make sure it isn't touching the frame and engine case at any time. 41 chain is wider than a HD415 so that will cause clearance issues too.

 

[wan37]

There’s one thing to check your master link clip has to be on a certain way too . The master link clip closed end has to go in the direction of travel first . So the closed end of clip goes in the engine first. That can make the chain come apart if on the wrong way.

 

[Sidewinder Jerry]

The others have brought up some good points to investigate. Here's another issue to consider. All chains aren't created equally. Even if everything is as it should be, an el cheapo chain can still break.

 

[Axl Myk]

Run a straight edge across the rear sprocket and make sure it aligns with the motor sprocket.
Quality control isn't a high priority, so remove any burrs on the sprockets.

 

[darwin]

The others have brought up some good points to investigate. Here's another issue to consider. All chains aren't created equally. Even if everything is as it should be, an el cheapo chain can still break.

Isn't that the truth. M/C chains for just one 250 can range from $20 to $200. 100 different choices.

 

[Sidewinder Jerry]

Run a straight edge across the rear sprocket and make sure it aligns with the motor sprocket.
Quality control isn't a high priority, so remove any burrs on the sprockets.

Even with everything perfect I've seen cheap chains break. Most common situation is going up a really steep hill with a high ratio.

 

[FatherMoonMan]

I would venture to guess that something is not aligned properly...The rear wheel, of course needs to be running straight and "true", meaning no visible wobble side to side movement etc, and check that the bearing in the rear wheel when holding the tire and trying to manipulate it it sided to side should also show no movement.

Does the rear sprocket, when spinning the wheel show any warpage at all...if so, the rag joint holding it to the wheel is not correct...there should be no more than a 16th of an inch of play in that sprocket so as not to be twisting/stressing the chain.

Well, thats a good starting point for you to start looking...lol...DAMIEN

this may have been one of the factors, the rear wheel was a bit wrapped but tightening the spokes seems to have fixed it