Rear belt deflection adjustment
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Cruiser
Joined: Jan 2011
Posts: 202
Likes: 2
Rear belt deflection adjustment
I have a 1991 FLT and adjust rear belt with factory type tool using 10 lbs pressure at middle lower area of belt. The deflection in my belt now measures 15/32" and manual says this is 5/16-3/8" deflection at LOWER area of belt with 10 lbs pressure. Some aftermarket manuals say to apply 10 lbs pressure at bottom of belt and measure at top of belt (but factory manual says to measure pressure and deflection at lower area of belt). If I use this after market manual (Clymer) instruction, my belt is way too tignt with almost no play at top area of belt. My belt deflection falls at extreme high or slightly above high end of tolerance range with factory manual, however my belt is much tighter than belts I have felt on other similar bikes (including at dealer showroom). When I twist belt at lower area of belt it does just twist to the 45 degree angle and no further. Many in showroom twist to 90 degrees. Are most belts adjusted too LOOSE? I have read that it is better to have a slightly tighter belt than a slightly loose belt. Any opinions welcome.
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,198
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From: NW AR
A slightly loose belt is better, in my opinion.
Always follow the factory shop manual The Clymer manuals are only for a second opinion.
You press up 10 lbs on the little gauge, and measure how far up it went. That should be about 3/8". Nowhere in the book does it say twist the belt to judge tightness. That's a subjective test that some people use.
Always follow the factory shop manual The Clymer manuals are only for a second opinion.
You press up 10 lbs on the little gauge, and measure how far up it went. That should be about 3/8". Nowhere in the book does it say twist the belt to judge tightness. That's a subjective test that some people use.
Club Member
Joined: Apr 2011
Posts: 5,802
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From: SE Louisiana
If you didn't already, jack the rear wheel off the ground and rotate tire to check for the tightest spot on the belt by pushing up and feeling the tension on the bottom, right by that little sight window in the gaurd, or about in the middle, about every 1/4 turn.
Some have tighter spots than others and some are about even, but I would at least check it.
Adjust at the tightest point.
Some have tighter spots than others and some are about even, but I would at least check it.
Adjust at the tightest point.
Tourer
Joined: Jan 2012
Posts: 259
Likes: 1
From: Kingston, Ontario
+1 to both comments above. The clymer book is for pictures only and you will be left scratching your head and fixing extra parts if you us it. Twisting a belt to test tightness is NOT the way to check and I believe that is stated in your factory manual. Once you get used to doing it it becomes natural and should be a part of your regular maintenance most belt failures are due to improper adjustment.
Grand HDF Member
Joined: May 2008
Posts: 4,326
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From: Picayune, Ms.
I have always adjusted my belt by twisting it, never more than 45deg. never less than 30deg. Use only two fingers and your thumb. Roll it between them.
By not correctly following the manual the belt only lasted 115,000 miles, and then failed due to external injuries. (something cut the protective coating and allowed two of the steel belts to rust to the point of failure)
Just my .02
By not correctly following the manual the belt only lasted 115,000 miles, and then failed due to external injuries. (something cut the protective coating and allowed two of the steel belts to rust to the point of failure)
Just my .02
Club Member
Joined: Jun 2007
Posts: 45,429
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From: Bedford UK
Stop right there and don't over think this! 15/32" is close enough for rough work. Ride on and enjoy - forget everything else you wrote!
Stellar HDF Member
Joined: Jan 2013
Posts: 2,747
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From: Vermont
As Graham said dont over think. Get it close and FORGETABOUTIT. Belts don't fail..surrounding parts or debris cause failures. Have fun and ride the heck out of it.
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Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
I usually eyball it with 10lb tool, keep it on the looser side. Then if I hear it starts chirping, just tighten it a bit (half a flat).
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Seasoned HDF Member
Joined: Dec 2010
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From: Coromandel Peninsula New Zealand
Loose is not better!!!!!!! Don't ever leave it looser....tight is better, you run them tighter with big HP motors too.
Use the tool and measure the deflection in the window that is cut into the lower belt guard for this very purpose.
If no belt guard then measure the deflection at the point where the tool presses on the belt.
If you leave it loose it can jump a tooth and then its toast.
Use the tool and measure the deflection in the window that is cut into the lower belt guard for this very purpose.
If no belt guard then measure the deflection at the point where the tool presses on the belt.
If you leave it loose it can jump a tooth and then its toast.
Thread Starter
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Cruiser
Joined: Jan 2011
Posts: 202
Likes: 2
Thanks Spanners. I am not trying to be **** about this but when adjusted by the manual with the tool, the belt "feels" tight to me. The reason I asked the question is I do not want to ruin by trans bearing.