Chain, Chain, Chain

I alluded in my recent post on camping in the Smokies that I ran into some trouble of my own making while traveling this year. When it comes to maintenance, I've often had to learn the hard way that something needs to be completed in the interval specified in the owner's manual. The challenge when dealing with components that rely upon measurement of wear patterns arises when trying to extend the life of the component to it's maximum. My trip to eastern Tennessee this year taught me that when a chain reaches the end of it's natural life, it has absolutely, positively reached the end of it's natural life. There can be no wringing a few extra miles of usefulness out of a worn drive chain.

My preferred destination is Tellico Plains, the starting gate of the Cherohala Skyway. From my home in northern Kentucky, I must ride over 350 miles to reach this town. In March of this year, I set out with an already taxed drive chain for an extended weekend in the mountains. First let me say that my maneuver wasn't just foolish, but dangerous. Of course, hindsight is always 20/20. What started as poor judgement on my part could have easily become a costly mistake. A worn drive chain can jump sprocket resulting in a crash and yet another trip by bus to the emergency room. In many regions of the Appalachian mountain chain, a rider could leave the road, disappear into the brush, and not be recognized for days, if at all.

At the least, worn drive chains no longer respond appropriately to adjustment and can damage other drive line, such as sprockets, or transmission components. Fortunately for me, none of the above incidents occurred. I limped the Ninja home after a single day and arrived in my driveway with a chain seriously binding in more than one location. I decided to spend the remainder of my vacation disassembling the final drive and thoroughly cleaning my machine. As the pictures indicate, a good bath was sorely overdue.

All body panels were removed and cleaned from each side. One of my least favorite aspects of chain-driven machines is the chain itself. While this method of drive is relatively simple to maintain and affords a tremendous amount of power to the rear wheel, I've never been able to keep one very clean with the type of riding in which I engage. Old chain gore refuses to be scrubbed away without a little labor. After several days accompanied by an ample supply of elbow grease and Simple Green, a motorcycle was discovered beneath the grime on wheels I'd parked in the driveway. I took the time to change my oil and filter, replace the rear tire, inspect the brake pads, and check the frame for breaks in the welds, a failing reported by several web communities on the first generation of this Ninja model.

And the chain needed replacement. While this requires a few specialized tools, such as the chain breaker and riveting tool pictured to the left, the procedure is relatively simple. Manufactured by Stockton Tools, the instrument I purchased came with simple instructions, and with the aid of several on-line how-to tutorials, I performed the job myself. Keep in mind that the last time I replaced a chain was with my father's assistance when I was ten. Very simply, the old chain needed "cutting" and it's replacement required that it be sized, which involved removing links to bring the chain to the proper length. In this case, that would be 114 links. The chain I purchased, of the x-ring variety, arrived with 120 links. Adhere to the old axiom, measure twice, cut once. An inability to perform basic math will result in...well...let's just say I measured once and paid twice.

The trickiest part of the entire process comes when placing and riveting the new master link. Rather than use a clip-style master link, which involves a retaining plate slid over the ends of the link pins to hold the master link together, I utilized a rivet link. The outer plate of the link is pressed into position using the riveting tool and then the heads of the link pins are mushroomed out to hold the outer plate in place. Much of this must be done by feel and careful inspection to avoid pressing the outer plate on too tightly. An over pressed master link will damage the tiny rubber x-rings and cause the new chain to bind. Needless to say, I learned my lesson from my first mistake and took my sweet time.

Another hotly debated topic contests whether the sprockets must be replaced at the same time as the chain and whether both sprockets should be switched out at the same time. I chose to replace the smaller drive sprocket due to wear, a slight forward lean of the teeth upon inspection. I did not replace the rear sprocket as the teeth showed an even and predictable decline. Several factors influence how fast a sprocket will show wear. Aluminum sprockets, for instance, usually wear faster than those made from steel, and the differing alloys used by various manufacturers can deteriorate at varying rates.

Averaging 15K-20K miles per chain is considered by most sources I consulted, including my regular mechanic, as high mileage. My old chain accumulated 25K miles, and when I think hard about it, probably should have been replaced between 20K and 22K miles. I sometimes fall into the trap of trying to extend the life of my machine's components. In reality, some parts are just designed to wear out and be replaced. This is the third chain fitted to the Ninja, and the first replacement I've undertaken myself. While not altogether complicated and a learning experience, I dream more frequently of shaft drive.