Why Motorcycle Chain Loose

If you find that the chain is loose on the road, don’t panic. This is rarely a major mechanical failure. The chain feels loose, usually because of the so-called “chain stretching” (in fact, the natural wear of the pin shaft), the chain link jam caused by inadequate lubrication, or the natural wear of the chain and the gear plate as the mileage increases. As long as the chain sag exceeds the standard in the maintenance manual (usually 1-1.5 inches of vertical swing), it should be adjusted. If the chain is too loose, it will slap the rocker arm, and there will be a sense of frustration when refueling the door, but this thing can be solved by yourself: loosen the rear axle nut, adjust the tension of the chain, ensure that the rear wheels are aligned, and then tighten it. If you find that you have to adjust it every few hundred kilometers, it means that the chain and chainring have come to an end. Don’t hold on hard and replace it quickly.

Understand The Core Reasons For Loose Chain

A loose chain is something that cannot be bypassed by playing with a car. If you find out the reason, you will not have a headache when you maintain it:

The so-called “stretch”: In fact, the metal chain link itself will not be elongated. It is the pin shaft and bushing inside the chain that are worn out, resulting in a small gap, which makes the chain look longer.

Chain link stuck (dead knot): Inproper lubrication will cause O-ring or X-ring to dry and crack, and the chain link will not rotate properly. At this time, the chain tension is not uniform, some places are tight, some places are loose.

Natural wear: the mileage goes up, the chain and the toothed plate are grinding. This is the inevitable result of the power transmission process, and it is also the most common loss.

How To Judge Whether The Chain Is Too Loose?

Check the maintenance manual is the safest:

Check the manual: The standards of different models are different. Go and look at your manual, which clearly states the recommended margin for the car.

Measurement: find the middle position of the front and rear gear plates, push up the chain, and measure the shaking distance. If the target given by the manufacturer is exceeded, it is really loose and must be dealt.

The Chain Is Loose And Does Not Adjust, What Are The Consequences?

If you let it go, the riding texture will be greatly reduced:

Metal slapping sound: You will hear a noticeable metal slam sound, which is the sound of the chain slapping on the rocker arm after it is loose.

Throttle setback: There is a delay in power transmission. When refueling, the chain must be tightened before it can drive the rear wheel. This momentary makes you uncomfortable to accelerate and even affects the control.

Hands To Teach You How To Adjust The Chain

As long as the chain has not reached the end of life, follow these steps:

Loosen the rear axle nut: use a suitable wrench to loosen the rear axle nut, do not remove it, loosen it until the wheels can move.

Use adjuster: find the adjusting bolts on both sides of the rocker arm, keep the rotation range of both sides consistent, push the wheel back, the chain will be tight.

Alignment: Be sure to look at the scale on the rocker arm to make sure the rear wheels are straight. The rear wheel is not right, and the chain, chainring and even tires wear out very quickly.

Tightening and retest: after adjusting the tension, tighten the rear axle nut according to the torque in the manual. Re-test again after tightening, because sometimes the wheel position will slightly shift when tightening the nut.

When Is It Time To Change The Chain And Chainring?

Sometimes, the chain is just a “palliative”. If you find that you have to adjust it once for hundreds of kilometers, this is already hard evidence that the life of the chain and the toothed disc is exhausted.

At this time, no matter how you twist the adjustment bolt, it is only a temporary survival. The metal fatigue has exceeded the limit, and the tooth tips of the toothed discs are estimated to have been ground into hooks. For the sake of safety and power, don’t save money, it is the right way to replace the whole set (chain gear plate).

Author: Mark Thorne

“Hi, I’m a lifelong motorcycle enthusiast and DIY mechanic with over 12 years of experience on the road. I’ve spent countless hours in the garage perfecting the art of bike maintenance. ”