Tuesday Tip: Tension

Suzuki’s Tony Berluti Adds Cam Tension To The Lives Of RM-Z450s Everywhere…

Intro" Ryan Cooley // Photos" Garth Milan

You may be wondering if this installment of Race Shop even pertains to you or your steed. Well, if you’re an RM-Z450 owner, it does, so pay close attention—your bike’s life depends on it! Although a manual adjuster is said by those in the know to have some possible added performance benefit, the crude reality is that your RM-Z450 does not have an automatic cam chain tensioner, which means more work for you. You see, cam chains, like any other chain, will stretch over time. And just like your bike’s drive chain, proper adjustment is necessary for optimal performance and bike life. It is most important to adjust your cam chain, like your drive chain, after the first few hours of riding the bike, as chains are most susceptible to stretch when they’re brand new. Is there performance to be gained with the proper cam chain tension? Possibly, but it’s more of a wear issue than anything. However, if the cam chain gets too loose it can slip timing, and if it slips timing, it will not only significantly lower performance, but it will also significantly damage the motor. Don’t panic! Once Tony B. walks you through the adjustment, you’ll quickly realize that it’s not only simple, it can easily become a part of your regular maintenance. Take it away, Tony…

STEP 1: Wait a second… Put down that wrench! Before you start ripping your bike apart, I highly recommend that you begin by cleaning it thoroughly—at least in the engine area that you’re about to work on. Now, make sure your fuel petcock is turned off, grab your T-handles, and remove the seat and gas tank in order to expose the valve cover on the top of your motor.

STEP 2: Now with easy access, reach down between the frame tubes and pull the spark plug cap straight up and off of the cam cover. It’s tight and may take a bit of force, but trust me, it will pull off. With your 6mm Allen socket, remove the two cam (valve) cover bolts, and lift the cover up and off of the motor, making sure that the cam cover gasket lifts up with it.

STEP 3: The cam chain must be adjusted with the piston positioned at top dead center (TDC) on the compression stroke. TDC on the compression stroke is the position that the cam chain will be at its loosest point, and thus any tension adjustments that may be required are more effective at this position. To achieve TDC, I slowly turn the motor over by using my hand to lower the kickstarter until TDC is achieved.

STEP 4: How do you know when you’re at TDC on the compression stroke? The first indicator is to inspect the position of the cam lobes. At TDC, the lobes should be facing away from the tappets, or “buckets, which are the circular-shaped pieces found directly below the cam lobes. In addition, you must also check that the indicator dots on each of the cam gears are also pointing away (facing straight up). With the lobes and the dots in sync and indicating TDC, you’re ready to adjust the tension.

STEP 5: You’ll find the cam chain tensioner on the left side of the motor. With a 12mm wrench, break the 12mm lock nut loose by turning it counterclockwise. Now, grab a 4mm Allen wrench to loosen the cam chain tensioner adjusting screw. The cam chain tensioner is spring-loaded, so as soon as you loosen the 4mm Allen, the spring inside the mechanism will automatically set itself into the proper position and tension. To lock the setting into place, retighten the 4mm Allen first, and then tighten the 12mm lock nut.

STEP 6: Before reinstalling the cam cover, I recommend putting a small dab of silicone or Suzuki Bond on the four corners of the head where the cam cover gasket makes contact (at the corners of the half-moon-shaped indentions) to prevent potential future leakage. Now place the cam cover with gasket back onto the head surface, and torque the two 6mm Allen head bolts to 9 ft. lb. of pressure. Push the spark plug cap back into place, ensuring that it pops all the way down into its proper position. Reinstall the tank and the seat, and go ride!