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Nube error - Messed up on alternator belt tensioning

M

mhallman

Member
I replaced the HES this past week on my 2010 R1100RS. I've had the bike a couple years and decided to put a new belt on as well since I wasn't sure when it had last been replaced (currently 68,000 miles). Read the Clymer and watched video to properly adjust the tension on the belt and got to it. UNFORTUNATELY, I didn't remember (or never realized) that the reverse on my torque wrench wasn't for measuring torque. I thought I'd learned my lessons about if it feels wrong, it probably is. Regardless, I torqued down way too hard and cracked the tensioner nut (Clymer calls it an idler I think). Does anyone know where I can find one of these?
 

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mhallman said:
Thanks for that. Will bookmark this page for future use. Off to get a reversible torque wrench...
Click to expand...

You do not need to overthink this. It is just a rubber drive belt. If you tighten the belt until you are able to twist it 90 degrees at the midpoint between the pulleys you will be just fine. That is not too tight. If it is too loose it will squeak on engine startup. If it were too tight the part that would be damaged is the front bearing in the alternator. I used this technique on my R1150R. That alternator was still alternating at 177,000 miles when I sold the bike. I use this technique on Voni's R1100RS and the alternator is still OK at 412,000 miles. The commutator is a bit grooved but the bearing is fine.
 
Thanks Paul. As someone trying to "learn-as-you-go", it's easy to overthink things. It's fun to work on the bike, but not when you end up fixing one thing but breaking another...
 
I have used the method of belt tensioning that Paul mentioned for many years as well.
This 90 degree tension check is actually spot on when you check it with a torque wrench..YMMV
 
PGlaves said:
If you know what the tension spec is supposed to be? Or is it a universal value?
Click to expand...

There are a bunch of them out there based on the belt only. I recently saw Gates used a piece of tape. You applied the tape to the belt. You tightened the belt and when the tape broke, that was the perfect tension for the belt.
 
PGlaves said:
You do not need to overthink this. It is just a rubber drive belt. If you tighten the belt until you are able to twist it 90 degrees at the midpoint between the pulleys you will be just fine. That is not too tight. If it is too loose it will squeak on engine startup. If it were too tight the part that would be damaged is the front bearing in the alternator. I used this technique on my R1150R. That alternator was still alternating at 177,000 miles when I sold the bike. I use this technique on Voni's R1100RS and the alternator is still OK at 412,000 miles. The commutator is a bit grooved but the bearing is fine.
Click to expand...

What Paul said. Been doing the 90 degree twist on my 2004 RT since it was new. Now currently at 129k, and on the original alternator with only a couple of belt changes.

Don't over think it.
 
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