Race Shop: Proper Chain Adjustments with Craig Monty

By Craig Monty

[IMAGE 1] Making power and transferring your bike’s ponies to the ground takes more than a beefed-up, aftermarket cylinder. In fact, the only thing standing between the engine’s countershaft and the rear wheel is the chain. Unfortunately, many riders simply ignore this crucial link to power, which can ultimately lead to a snapped link and a premature drive home from the track.

Knowing that there are several steps that must be taken to combat the problem of chain failure, TWMX headed off to the Yamaha factory to see what kind of useful information we could uncover from David Vuillemin’s factory tuner, Craig Monty. Monty was not only willing to oblige, but he was very adamant about the subject of chain care. “Not only does your chain need proper lubrication, but great steps must be taken to ensure correct, even adjustment. Though the topic sounds pretty basic, there are actually a number of things that need to be done to your bike to make sure you don’t suffer a chain-related DNF.” Do It Right From the Start

According to Monty, before you even ride on a new chain (or a new bike, for that matter), it is a good idea to adjust your chain with more than the “three fingers” method. Though this technique will work when you’re in a crunch, it is not the best way to make an accurate judgment on whether your chain has the correct amount of slack in it.

The best way to make that decision is to spend an extra couple of minutes and check the slack with the chain in a completely horizontal position. This will put the chain in its most stretched state, allowing you to see if it is too tight. To do this, remove the bottom shock bolt from the bike and lift the rear wheel up. Once the chain is horizontal, there should be about an inch of free play: any tighter and you run the risk of snapping it. Always check for this free play directly above the plastic chain guard on your swimgarm. After you have altered your chain adjusters accordingly, reinstall and tighten your bottom shock bolt.

Not Done Yet

[IMAGE 2]Now that you are certain that the chain is adjusted precisely, the next step in ensuring proper performance from your rear end is to tighten the chain adjusters correctly. Monty recommends using two wrenches here, with pressure on both the bolt and the nut.

“The chain adjustment nut occasionally comes loose, plus there is a good chance that you will round off the nut if you tighten it by itself. When working on David’s bike, I prevent this is by tightening just the nut at first, but barely. Then I put a wrench on the bolt, and I tighten the nut and bolt simultaneously. The reason you want to lightly tighten the nut first is so that you don’t lose your precise adjustment. Once it is snug, though, you need to tighten them both.”

After both chain adjusters are tight against the swingarm, the rear axle is next to be tightened. When doing this, don’t make the mistake of simply pushing the rear wheel forward to snug the axle against the chain adjusters, as this can lead to misalignment. This will not only cause your wheel to spin incorrectly, but can also lead to premature wear on your brake pads. Instead, Monty advises putting a T-handle between the gaps in your sprocket teeth and the chain. Once the T-handle is in place, roll the rear wheel backwards, which, through the magic of leverage, will force the axle spacers against the adjusters and allow for even tightening of the rear axle.

“Though I see a lot of riders using a wrench for a similar effect, I recommend using a T-handle. This will keep your sprocket and chain from being damaged by the wrench, which isn’t even close in shape to the recesses in the sprocket teeth.”

[IMAGE 3]In a perfect world, your chain should now be adjusted with exact precision. According to Murphy’s Law, however, this is not always the case. The problem is that sometimes your bike will come from the factory with chain adjustment marks that don’t line up accurately. This is a rare ooccurrence, but to be on the safe side, Monty recommends using a special tool to make sure everything is kosher. Monty’s tool was custom made by Yamaha and is basically an aluminum rod with two points that measures the distance from the rear axle to the swingarm’s pivot point (see photo). Craig measures both sides of the bike, which reassures him that the pair of chain adjusters are exactly even. Now that your chain is adjusted and your wheel is tight, don’t forget to lube the chain before riding and in between motos. This is as important as correct adjustment to prolong the life of your chain and sprockets.