Annoying drive belt "chirp"

[stu058]

hey ken, don't know if you have stock pulley or not but my chirp was caused by a worn pm pulley that the teeth were worn down almost to a point. those teeth should have a round profile at the top. if you over thighten belt it will accelerate the wear. i would call phil at supermax.com. i installed a plastic pulley from him and couldn't be  happier. give him a call     stu

[vans24]

I apalogise , I didnt mean to give you bad advice, as we all know the  manual is always right. either way the extra 1/8 I tightend the belt  took care of my problem. but it is my bike and if the tranny  falls off or the belt breaks it is on me.  sorry again. hell it might not even be what's making the  chirp anyhow

[CrazyRay]

vans24,
I don't think that was bad advise necessarily. It is hard to get the belt tightness just right, especially doing it alone. Most of the time, tightening the belt a little more is what has worked for me. If we have to tighten it more than the manual recommends to get the chirp to stop, then maybe something else is going on. I think it is better to have a belt that might be slightly loose than one that is slightly too tight.

[Ken R]

I apalogise , I didnt mean to give you bad advice, as we all know the  manual is always right. either way the extra 1/8 I tightend the belt  took care of my problem. but it is my bike and if the tranny  falls off or the belt breaks it is on me.  sorry again. hell it might not even be what's making the  chirp anyhow

Vann, it wasn't the advice so much as it was the "horse" comment.   

I have time today and am going to try everything, including belt tension.  It is difficult to determine the right amount of deflection when alone; and even harder to tighten the axle alone after finished.  A couple of years ago when I had help and made sure that the belt was adjusted to the factory recommendations, I scribed a mark on each of the adjustment cams for future reference.  For the past couple of years, I've been simply aligning to the scribe marks tightening the axle nut, check to make sure it didn't move, and then quickly check to make sure the belt seemed to be adjusted O.K.   I'll be a little more precise this time.   As Hippo suggested, I'll rotate the wheel backwards to see if the belt moves to the other side.  I'm also going to check for cracks in the pulley, pulley bolt torque, and wobble.  Checking the front motor mount isn't easy with the oil cooler in place. 

I enjoy seeing other's pictures; so I'll take and publish a few if they illustrate anything worthwhile.

Ken

[ICANTD55]

This may help.
http://www.pingelonline.com/rear_sprocket_spacer.htm

[HIPPO]

I always used the method of twisting the belt between thumb and forefinger to check tightness.
Always check it with the bike cold, like after sitting overnight.

The other thing with these cam adjusters, the tension can't really be adjusted properly loosening and tightening. You start giving it tension, if you find you need more you can give it a little more, but if you find that it is too tight then it is best to start over from tension fully relaxed and both cams positively against the stops on the swing arm.

If you just loosen it a little it has a tendency to pull itself out of alignment because one cam is fixed and the other one has slack on the axle. Sometimes a new cam piece that fits better on the axle helps if the non welded cam has too much slack on the axle.

[hdpegscraper]

Ken, glad to see that your gona check out that front motor mount. Cause on my Dyna, if I raise the front of the motor, it will loosen the belt tension. Now you would prolly need a lot of travel to give you a problem, but its worth checkin.

[Ken R]

O.K. I did everything except engine/transmission alignment.  (Don't have the alignment tool yet). 

But I did use Frank's suggestion of rotating the wheel backwards.  Sure enough, the belt moves to the inside flange.  Back forward and it moves against the right-side flange.   Seems pretty even.   So for now, I'm discounting alignment.

Checked the swing arm locknut torque.  Had to add 4 ft pounds to get it to 40ft lbs.  Also checked the pivot mount bolts and torqued them to spec.  They needed additional tightening, too; to get there.  All this stuff is in the 10K mile check-up.  Haven't touched any of mine since almost 10K. 

Unbolted the oil pump and checked the front mount.  No cracks or anything.  The center nut was to specification.  (about 10K ago, it needed additional tightening, but not this time).

The bolt that goes through the eyelet on the front adjuster was loose.  I could almost turn it by hand.  But I don't think that it contributed to any problems (yet). 

After all of that, I checked belt tension.  It seemed rather light.  Spec says that it should be adjusted to 5/16" to 3/8" deflection when pushed up with 10 pounds of pressure without rider's weight.   (1/4" to 5/16" with a rider) 
Mine easily deflected to 1/2" to maybe even 3/4" with no rider. It was definitely loose despite that my scribe mark was still centered on the adjuster nub.  Has the belt stretched?  I didn't think carbon fiber belts would stretch.  (I know metal chains will, but thought carbon fiber stretch was minimal).   So I loosened the axle nut on the right side and adjusted the axle with cams from the left.  Didn't overshoot, so one adjustment did the trick.  I removed the left shock lower bolt, and then lowered the motorcycle to compress the right shock while on the sidestand to simulate a person on the motorcycle.  Removing the bolt also allows my 36mm wrench onto the axle. 

Put the covers, saddlebags, oil cooler, etc. back on and went for a little ride.  Didn't hear any chirp. 
Although I found maintenance that was needed, the drive belt not to spec was probably the culprit.  Using a centerpunch, I re-marked the position of the cams. 


I took pictures of everthing I did, but upon review, they seem worthless.  I won't take up the bandwidth. 

Edit:  Forgot to add that the wobble was .026", measured at the pulley flange.  I couldn't find a specification.  They may ALL be like that.

Ken

[HIPPO]

Good.
Temperature makes a difference on how the belts feel as far as tension. Here from summer to winter it can be 65 - 70 degrees easy. The colder the weather they looser they feel.

[Memnar]

My buddies 05 Soft tail had a rear drive belt pulley wobble - he bought it new and I think it had the wobble from day one fresh off the dealer floor. It squeaked a little but he couldn't hear it and only I saw the wobble.

So anyway maybe the rear pulley has the wobble from the factory....

[floatyguy]

Ken

My previous experiance with the "Chirp" (sounds just like a bird chirping on accleration and deceleration) is belt tension.
When you checked the tension did you have a person sitting on the bike that was equal to your weight or close to it? If I remember right the manuals say it must be checked with a rider sitting on the bike. If you have the belt tension tool (HD) the instruction will not say anyhthing about a rider sitting on the bike. On 5 speeds it should be 3/8in-5/16in with 10lbs of force applied to the belt when adjusting.

[Ken R]

Ken

My previous experiance with the "Chirp" (sounds just like a bird chirping on accleration and deceleration) is belt tension.
When you checked the tension did you have a person sitting on the bike that was equal to your weight or close to it? If I remember right the manuals say it must be checked with a rider sitting on the bike. If you have the belt tension tool (HD) the instruction will not say anyhthing about a rider sitting on the bike. On 5 speeds it should be 3/8in-5/16in with 10lbs of force applied to the belt when adjusting.

My '02 manual gives two specifications:  One with rider on the bike (1/4 to 5/16" with 10 lbs deflection) and one with rider off(5/16" to 3/8"with 10 lbs of deflection).  The manual doesn't say whether the motorcycle should be on the sidestand in the rider OFF condition. 

I jacked the bike up with my scissor jack, removed the left hand shock absorber bottom bolt. and swung the absorber out of the way.  Then lowered the motorcycle down and onto the sidestand.  The rear wheel suspension compressed approximately the same as with me sitting on the bike.  So that was my set-up.  It's as close as I can get to the specified adjustment.