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Finishing Driveline Service- 

Align and Tensioning the belt plus reassembly of the outer primary. 

The belt seems to be one of the more misunderstood and feared maintenance items on motorcycles.   Despite what people may initially think, they are incredibly durable and strong.   I know of many people who have gotten over 100,000 miles out of their belt.  

Alignment of a Harley belt is critical to life of the belt and handling of the bike.  Especially on the rubber mounted Dynas and baggers. If you have misalignment of the belt, it will not only make the bike track slightly out of line, but it can create a bounce or tension in the driveling that turns into a “tank slap” or a “death wobble.  *Check your engine mounts too if you have this problem. 

Let’s get started with alignment of the belt.  Make sure the belt is looped over the pulleys and in place then install the axle and all the spacers.   I would recommend snugging up the axle nut just to make sure everything is seated and still spins properly.  Loosen the axle back up enough that the axle can be adjusted forwards and backwards. Now you will want to turn the axle adjusters in at an even rate until the belt has a moderate amount of tension, and you can just eyeball the alignment at this point.  

On the dyna there is a small hole in each side of the swing arm just in front of the axle. This hole is a reference point use for the belt alignment. Alignment on the Dyna is measured from this hole to the center of the swingarm.    You will use either Harley’s special tool or dial calipers to measure the distance from the hole to the center of the axle. This measurement will be compared with the measurement on the other side.  As you tighten the axle adjusters to zero in the alignment, don’t forget that you are also tightening the belt so you will need to keep an eye on that tension.  I generally align within .062” (1/16th), then set tension by turning each screw in an even amount.  ¼ turn left, ¼ turn right, then check tension again.   

The factory recommends 5/16 to 3/8” deflection with 10 pounds of force, and of course, they sell a tool too check this measurement with.  *this tool can be acquired online for under $30. I once was told you can check the tension by twisting the belt with your fingertips.  You should be able to twist the belt to 45 degrees with your fingertips, but no more, no less.   That proven to be a pretty reliable measurement over the years and miles  Once you have nailed down the alignment and belt tension, torque the axle nut to 60-65 ft lbs, and then reinstall the retaining clip on the axle nut.  Your belt will walk back and forth on the pulley a little.  However it should never look like it is hard against one side or look like it is trying to climb out of the pulley.  Sometimes I touch each side to make sure it is not getting hot, because if there is heat, you may have alignment problems. 

Now that the belt is installed, aligned and tightened down, we will reinstall the primary cover. *No reason that this could not have been done before the belt.  Ensure that the gasket & gasket surface is clean and free of burs.  Hang the primary gasket on the alignment studs and reinstall the primary cover.   Start each bolt in be a few threads and be careful to make sure the gasket aligns with each bolt.  I once trashed a new primary gasket by not doing this.  The Cometic gasket I use has a metal internal frame, which helps to hold the shape of the gasket. Once all the bolts are started in, torque them to 108 inch pounds, in the pattern specified by Harley. I exclusively use Cometic Gasket products.  Their micro cell primary gasket has been working for me for many miles, and the rest of their products have always served me well.  Plus they are in the Greater Cleveland Area, so it is always good to support local products.  

Add your favorite oil to the primary. DON’T FORGET TO DO THIS BEFORE YOU REINSTALL THE CLUTCH COVER OR SHIFTER PLATE! Personally I recommend Synthetic primary oil.  If it is not easily available try 75-140 gear oil with friction modifier.   I have heard of some people using ATF transmission fluid.  That stuff is entirely too thin for your chain and primary tensioner. You need at least a 50 weight oil in there. 

No break in required, just take it out and ride the snot out of it.  Periodically stop and check for leaks or parts or something coming loose.  After the first test ride I would recheck the belt tension every few tanks of gas.  It should not need any readjustment, but if there is a problem, now is when it will show up. 

Now if you are concerned because you don’t have the tools, garage, or the heated space to work on your bike this winter, stop on by Skidmark Garage and ask about membership. 4501 Hamilton Ave Cleveland Ohio. All are welcome, who welcome all. www.skidmarkgarage.com 

If you are unsure of what steps to take, contact me for questions, and consider taking a class. www.knoblemoto.com

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