Light Knocking sound when decelerating-GL 1100

[strapman]

Hi all!

I had refreshed an 1983 Interstate, put everything back together...included carb rebuild kits, new bearings in swingarm, valve adjustment, new belts and on and on. Upon initial ride last week, i hear a weird knocking noise only upon deceleration. Almost sounds like the drive shaft, but sounds to be lower in gear case---cant replicate the sound with bike on centerstand and shifting thru gears. No matter if i am in first gear or 4th, when i lay off the throttle (any speed) i hear this knocking sound, it goes away with more throttle. One thing that was not done yet was a carb sync...could what i'm describing be because carbs not synced?

Thanks!

 

[AlaskaWing]

Dont slow down??? :smilie_happy: :smilie_happy: :smilie_happy:

 

[slabghost]

We can't hear as you do. Could you post an audio or video with the sound or be as descriptive as you can? It may be driveshaft is slightly mis aligned or any of a number of things. Does it sound like tapping the valve cover with a screwdriver handle? Or more like tapping exhaust with a wrench? actual location of sounds can be very hard to find while riding.

 

[strapman]

I was thinking the same thing re drive shaft mis-alignment, but in my service manual it says nothing about aligning? just how to put back together? Is there any tips re driveshaft re-asembly sequence?

As mentioned, i cant duplicate the knock unless riding and laying off the throttle. I'll try to bring wife with a video camera and tray and catch the knock----somewhere i recall something about carbs out of sync could cause crazy noises too?

 

[joedrum]

hmmmm...take plugs out and see if one is drasticly different than others

 

[zman]

The primary chain will make a knocking sound especially if the carbs ore out of sync. I don't believe there is an adjustment but they are made to last a lifetime.

 

[Steve83]

If the primary chain is excessivly worn (stretched), it will make quite a racket. The spring-loaded tensioner only takes up the slack under load, during deceleration any slack is free to slap against the stationary tensioner. How many miles on the bike?

 

[dan filipi]

Steve83 » Fri Jul 05, 2013 3:42 pm[/url]":34o20mgd]If the primary chain is excessivly worn (stretched), it will make quite a racket. The spring-loaded tensioner only takes up the slack under load, during deceleration any slack is free to slap against the stationary tensioner. How many miles on the bike?

I've always wondered how that tensioner worked.
Mine slaps at idle then quiets when pulling in the clutch.

 

[slabghost]

I think backlander had a similar problem. He loosened all the mounting bolts and retightened in the order suggested in the manual and the noise disappeared.

 

[backlander]

Naturally you have to loosen all these bolts first and then torque to spec in this order. Right swing arm pivot bolt, left swing arm pivot bolt, left swing arm lock nut, rear axle nut, rear axle pinch bolt, four final drive to swing arm nuts, and then lower shock mount bolts.

 

[Steve83]

+1, except to avoid any confusion, there's only 3 nuts securing the final drive to the swingarm.

 

[slabghost]

backlander » Fri Jul 05, 2013 6:18 pm[/url]":950yopwd]Naturally you have to loosen all these bolts first and then torque to spec in this order. Right swing arm pivot bolt, left swing arm pivot bolt, left swing arm lock nut, rear axle nut, rear axle pinch bolt, four final drive to swing arm nuts, and then lower shock mount bolts.

Wasn't bouncing the bike a bit part of the procedure?

 

[backlander]

Sure is V, thanks, I forgot that step, bounce it up and down two three times to relax the stress. Helps relax my stress too. :smilie_happy: :smilie_happy: :mrgreen:

 

[David Mantle]

Deceleration knocks :builder: could be big ends , exhaust leaks near header, transmission or slack in drive train :moped: .
Just a thought - hope it helps.
Not that I know what I am talking about - sometimes big words :rtfm: sound good LOL.

 

[strapman]

Thanks for all the replies...found it! RHS dust cover for tapered bearings on swingarm did not seat properly when re-assembled and torqued, so the RHS of swingarm was off a hair...pulled everything apart tonite and now need new dust cover (old one smashed on one end)---will order and hope that was the problem!!!

 

[joedrum]

cool good find ..it has a chance to be it for sure

 

[slabghost]

Soak the dust cover in ATF. It might reform to it's shape.

 

[Ansimp]

:good:

 

[Steve83]

Cool - I hope that was the problem!

 

[AApple]

:clapping:
I love it when a plan comes together!!