Drive belt tension
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Tourer
Joined: Apr 2015
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From: xx
Drive belt tension
Looking at the service manual for 2019 Softails, and I'm a bit confused. The manual states that the guide has marks in 1/16th increments, however when I measure it with a ruler, they are actually 1/8th. The new manual also has new belt and service belt deflection amounts, which is new to me, as my older bikes just had one measurement. Assuming the increment mark size is just a simple manual mistake, the confusing part is - the service deflection amount is 1/2 - 9/16th, so basically 1/16th. That is a much higher tolerance than any other Harley I've had, and I'd say it would be difficult to measure it that accurately.
Are we really supposed to be striving for much smaller tolerance with the new Softails, or is this just a Harley way to make people not over-tighten the belts??
Are we really supposed to be striving for much smaller tolerance with the new Softails, or is this just a Harley way to make people not over-tighten the belts??
Road Captain
Joined: Nov 2017
Posts: 575
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From: Spokane, WA
The marks are confusing because they are counting the mark as one increment and the space between marks as one increment. Just substitute a 6" scale ( machinist rule) and it will be much more clear.
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Tourer
Joined: Apr 2015
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From: xx
Yeah, that I can measure. I'm just surprised how small of a tolerance Harley now specifies. Difference between too tight and too loose is only 1/16th of an inch! My RK was 3/16th... I measured in multiple points on my belt, and most were 10/16th, and tightest was 9/16th. I guess I'll just measure more often...
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Tourer
Joined: Apr 2015
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From: xx
By multiple points I meant rolling the bike a bit and remeasuring at the same place. Does the belt not stretch a bit unevenly just like a chain?
Road Captain
Joined: Nov 2017
Posts: 575
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From: Spokane, WA
Not to mention run-out of the sprockets also affects the belt tension. Just get it close and clean little stones and debris away from the belt and sprocket and it should last.
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Joined: Dec 2017
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From: Brisbane, Australia
Am confused, my HD service manual (94000529) shows the service belt tension deflection as 1/2”-9/16” and my 2018 Owners manual shows 1/4”-3/8” ... does anyone know which one is correct? Was there ever a service bulletin to correct this variation?
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From: Nunya.
The latest number is correct, the 1/2 to 9/16 when they came out at the end of 17 for the 18 model so very many were too tight at 1/4 to 3/8 and they made a lot of noise..
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Joined: Jun 2010
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From: Upstate New York
I modified my belt tension gauge by adding a scale to the side, marked in 1/8 and 1/16 inch increments. I sight the gauge against the edge of the belt guard with the belt slack, note the reading, then add the required force and note the final reading. Subtracting one from the other gives me the deflection.
I did this because my old Softail didn't have any measuring marks on the belt guard.