What Happens If Chain Breaks On Motorcycle

Once the chain is broken, the most direct reaction is that the rear wheels completely lose power, the engine will spin wildly because there is no load, and the speed will drop quickly.The real threat lies in the so-called “whiplash effect”: the broken chain will be thrown forward with great inertia, which is so strong that it can directly shatter the engine case (crankcase) or penetrate the front small drum cover, causing the oil to spray wildly and causing permanent mechanical damage. Other bad situation is that the chain piles up on the rear gear plate, causing the rear wheels to lock up instantly, throwing you directly into the danger of runaway sideslip. No matter whether the chain finally flew out or smashed the rocker arm, the most important thing you should do now is to pinch the clutch, stabilize the center of gravity, find a way to pull over safely, and then feel sorry for your mess parts.

Fatal Engine Case Impact

On many modern race and cruise cars, the front gear is located very close to the main engine case. When the chain breaks under acceleration, centrifugal force causes it to be thrown out like a metal whip. I have handled dozens of engines, all because the broken chain directly hit a hole in the crankcase. This thing is not easy to repair. Once the aluminum alloy shell is cracked, the oil will flow all over the floor (and may even get on your rear tire). The next thing you face is the engine disassembly or the whole replacement. In most cases, the maintenance fee plus parts fee is higher than the residual value of your motorcycle, which is basically equivalent to scrapping.

The Most Feared Rear Wheel Is Locked

Some riders are lucky and the chain slips directly onto the road, but the other is simply a top safety hazard. If the chain gets stuck between the rear chainring and the rocker arm, it holds the wheel like a dead bolt. When driving at high speed, the rear wheels lock up instantly, which will produce a lot of smoke and cause sideslip. This is probably the most terrifying thing a rider can encounter. I often tell my customers: in case of this, don’t compete with the motorcycle. Keep your eyes on the horizon ahead, hold the handlebars firmly and keep the course as straight as possible until you can control it and stop it safely.

Joint Damage Of Rocker Arm And Electronic Equipment

Even if the engine is saved, the swinging chain is uncontrollable. It often produces the following damage:

• Bite the rocker arm: Violent impact between metals will destroy the structural strength of the rear suspension.
• Break off the rear brake line: Let you only rely on the front brake to slow down in an emergency.
• Destroy the speed or ABS sensors: Today’s motorcycles rely on these electronic sensors, and flying chains can rip them apart in an instant.

I ‘ve even seen chains wrapped around the pedals, almost taking the knight’s ankles with them as well. Therefore, the condition of the main connecting piece (joint) and the alignment of the chain are not only maintenance items, but also the bottom line of life.

Why Is It Broken

On my lift, the chain never strikes for no reason. Usually before the accident, there will be one of the following 3 signs:

• The chain tension is not right: Too loose will cause the chain to shake or even jump teeth; if it is too tight, it will compress when hanging through the pit, and the chain will collapse under huge pulling force.
• Lubrication is not in place: No oil, O-ring or X-ring will fail. This can cause the chain links to “jam” and accumulate a lot of heat, making the metal pins brittle and eventually shear.
• Toothed Disc Wear: If your toothed disc is pointed like a shark fin, it can no longer hold the chain. It pulls the chain at awkward angle, putting the metal under stress beyond its design limits.

Prevention Advice For You

In order to ensure that you don’t have to go through these bad things, I strongly recommend that you do a routine check every 500 miles .

• Death Festival: Turn the rear wheel to feel if any part of the chain is tighter than the rest.
• Check the tension: Ensure that the sagging gap is within the scope specified by the manufacturer .
• Look at the “orange powder”: If you see orange powder around the pin, it’s internal rust gnawing at the chain.
• Watch for vibrations: If you feel a strange tremor on your feet last time you ride, don’t drag it.

Quickly replace the chain and toothed disc. Spending a few hundred dollars is like buying insurance, which can save you thousands of dollars in engine maintenance costs, and more importantly, avoid the risk of going to the emergency room.

Author:Dave Miller

Having seen firsthand the catastrophic damage a snapped chain can do at 70 mph—from shattered crankcases to dangerous high-speed skids—I’m passionate about translating complex mechanical issues into life-saving advice for riders.