rear wheel knocking

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Dalemac · #1 Post by **Dalemac** » Sat Jul 05, 2014 4:41 pm

Just been doing some minor work on the falco this afternoon and noticed that when the rear wheel rotated it makes a knocking sound at exactly the same point of every rotation.

I'll get the reat wheel out in the morning. Had enough fo today.

I'm thinking it is bearings. How hard is are they to remove and replace? Any hints?

Dale

fatboy · #2 Post by **fatboy** » Sat Jul 05, 2014 7:49 pm

TBH this sounds like sprocket wear/damage from what you describe.
Wheel bearing noise is constant as the bearing rotation is constant, if you see what I mean.
Get a hold of the wheel at 7o'clock and 1o'clock positions and push and pull, any play in the bearings will be more than obvious with wheel movement and clunking noise.
Hopefully you will find its a bit of crap on the sprocket teeth stuck on by chain lube

Dalemac · #3 Post by **Dalemac** » Sun Jul 06, 2014 6:09 pm

There is no play at all in the rear wheel. It only makes a knocking noise when spinning backwards.

I removed the rear wheel and checked the bearings - they all seem to look OK as far as I can see, including the sprocket carrier bearings.

Put the wheel back in without tightening the rear axle, spin in both directions and there is no knocking.

Tighten it up again and the knocking returns when spinning the wheel backwards.

Any more ideas?

Firestarter · #4 Post by **Firestarter** » Sun Jul 06, 2014 6:18 pm

Everything right on the brake calipers?

randomsquid · #5 Post by **randomsquid** » Sun Jul 06, 2014 6:44 pm

Dalemac wrote:
Tighten it up again and the knocking returns when spinning the wheel backwards.

Any more ideas?

Don't spin the wheel backwards.

As firestarter said - go for the caliper. I'd also have a look if the chain is rubbing on something. The wheel on my kwak is noisy if you spin it the wrong way. I've always assumed it'd because everything is bedded in going the right way. I've yet to break the 4mph barrier in reverse so I don't worry about it.

fatboy · #6 Post by **fatboy** » Sun Jul 06, 2014 7:18 pm

If everything looks good from the chain alignment and caliper point of view, you cant see any sprocket damage, rear axle nut torqued to 90nm, test ride feels ok, then I'd go with Mr Squids theory, a motorbike spends almost 100% of its time going forward (although this may not be true for every rider I know,some send too much time in the fast moving horizontal plane)
If you've ever heard a bus reversing out of its bay, the braking noise is awful in backwards mode,re everything bedded in for forward motion

Dalemac · #7 Post by **Dalemac** » Mon Jul 07, 2014 8:03 am

Yup, everything on the caliper and hanger looks fine, as is the chain adjustment.

Feels perfect to ride. Guess i'll just put it down as one of those random things!

Cheers for the advice all.

wayno · #8 Post by **wayno** » Mon Jul 07, 2014 8:58 am

If you've fitted a new rear sprocket it will probably be the sprocket mounting studs hitting the inside of the swingarm weld. It's because the new sprocket has a thinned out central disc, and the old one will be full thickness, mine was exactly the same and I made a spacer to take up the difference.

The sprocket is mounted differently to normal bikes so the sprocket thickness makes a difference (but only on some bikes as the weld height is where it catches.

Of course this may not be your problem, but check it out as a few others have suffered the same issue.

gramey · #9 Post by **gramey** » Mon Jul 07, 2014 7:54 pm

fatboy you say 90nm for the rear wheel spindle, interesting as I just had to have a new rear tyre fitted, courtesy of a screw through my tyre, and the garage said 120 nm's. He looked up the torque setting whilst I was there but by the sounds of it looked at the wrong setting???

TwinkietheKid · #10 Post by **TwinkietheKid** » Mon Jul 07, 2014 8:19 pm

gramey wrote:fatboy you say 90nm for the rear wheel spindle, interesting as I just had to have a new rear tyre fitted, courtesy of a screw through my tyre, and the garage said 120 nm's. He looked up the torque setting whilst I was there but by the sounds of it looked at the wrong setting???

The owner's manual says 90nm or 66 ft lb.

My Capo 1200 needs the 120nm.

Dalemac · #11 Post by **Dalemac** » Mon Jul 07, 2014 8:43 pm

wayno wrote:If you've fitted a new rear sprocket it will probably be the sprocket mounting studs hitting the inside of the swingarm weld. It's because the new sprocket has a thinned out central disc, and the old one will be full thickness, mine was exactly the same and I made a spacer to take up the difference.

The sprocket is mounted differently to normal bikes so the sprocket thickness makes a difference (but only on some bikes as the weld height is where it catches.

Of course this may not be your problem, but check it out as a few others have suffered the same issue.

Nope, same rear sprocket for like 2 years now. Definitely NOT hitting the weld on the swing arm, actually was the first thing i checked! but didn't mention it...

Dalemac · #12 Post by **Dalemac** » Mon Jul 07, 2014 8:47 pm

TwinkietheKid wrote:
gramey wrote:fatboy you say 90nm for the rear wheel spindle, interesting as I just had to have a new rear tyre fitted, courtesy of a screw through my tyre, and the garage said 120 nm's. He looked up the torque setting whilst I was there but by the sounds of it looked at the wrong setting???

The owner's manual says 90nm or 66 ft lb.

My Capo 1200 needs the 120nm.

Hmmm. THe service manual states 120nm/ 89ft lb for the rear spindle - Section 7.3.5.

Firestarter · #13 Post by **Firestarter** » Tue Jul 08, 2014 7:04 am

+1 for 120 Nm, that's what I've read and always used (and haven't sheared anything yet!)

wayno · #14 Post by **wayno** » Tue Jul 08, 2014 7:08 am

I used 120nm too, again from the service manual, hopefully this is right.

D-Rider · #15 Post by **D-Rider** » Tue Jul 08, 2014 7:37 am

TwinkietheKid wrote:
gramey wrote:fatboy you say 90nm for the rear wheel spindle, interesting as I just had to have a new rear tyre fitted, courtesy of a screw through my tyre, and the garage said 120 nm's. He looked up the torque setting whilst I was there but by the sounds of it looked at the wrong setting???

The owner's manual says 90nm or 66 ft lb.

My Capo 1200 needs the 120nm.

The Owners Manual that Aprilia put online says 120 Nm (page 62) for the rear wheel and 80Nm for the front.
http://www.martinpoll.dk/diverse/SL%20M ... nglish.pdf