Grinding sound when throttle is on

[Quapla']

I'm having a sound issue but I find it very hard to describe since it's so difficult to tell if it's coming from the engine, the chain/sprocket/rear wheel, or some other part of the bike I'm not sure how to solve it.

I only hear the sound when I have some throttle on. When I release the throttle completely the sound disappears. When I accelerate hard I don't hear it but that might be because of the wind/engine sound that masks it.

When I have the bike on the center stand and turn the rear wheel with my hands it makes a grinding noise (as if the rear brake pad is semi on). The wheel only turns halfway round (normal???). I have cleaned and relubed everything on the rear end of my bike (also the inner bearings after removing the rear wheel). It is aligned correctly and the chain slack is within the margins. Since the sound I hear is throttle related I'm at a loss at the moment. I don’t know what to check next.

Any suggestions are welcome.

p.s. bike has 8200km on it and fresh oil in it.

 

[TownsendsFJR1300]

With the bike turned off, rotate the rear wheel paying attention to where the grinding noise is coming from.... Are your brake pads in good shape (and not metal to metal?).

Does it make the noise when STOPPED(in neutral), when the engine is running?

Did you do any service work to the bike prior to the noise(new tires, brake pads, oil change etc?)

Scott

 

[Quapla']

Thanks for the quick response :thumbup:

When I turn the rear weal by hand I definatly hear a grinding sound as if the brake pad is still on...... but I can't say if it's commnig from the brake or the chain/rear sprocket. Also the wheel only turns halfway round when giving it a good push.

When the bike is standing still in neutral the sound isn't there. Engine runs like a charm.

I rescently took off the rear wheel and chain to clean / lube everything. The sound was gone for a while but it's back again now. We had a look at the inner bearings of the rear wheel and my dad (who is a mechanic) said it looked fine.

I can't remember the lube we used on those bearingings.... could I have used the wrong product :ban:

 

[TownsendsFJR1300]

Did the brake pads look ok? Try gently pushing the pads off the disc (with a thin screwdriver) then see how how it spins/makes any noises.. If that helps, pull the brake assembly and see if something is rubbing/not right/pads worn down..

If you haven't already, download the manual (from this site) it'll help in checking things over.....

If you had the rear wheel off I suspect something didn't go back together correctly. Re-check all your work paying attention to wheel spacers, chain slack(or lack of), etc. I don't believe the inner bearing spacer (inside the wheel between the two wheel bearing would fall down and not be actually inbetween the bearings(causing the bearings to crush inward as you torque the axle...). Make sure theirs enough chain slack and the rear wheel is straight... The wheel bearing grease shouldn't cause your problems.. You do need to rotate each of the THREE wheel bearings (the third is in the sprocket mount) and make sure there isn't any binding and their smooth. Pay close attention to the the on-line manual and the wheel spacers.....

Your starting to narrow it down....

Scott

 

[Quapla']

Allright will make this a weekend project I think

Still have to find time to install my 2Bros CF as well :spank:. Will post back when I've checked it.

 

[Quapla']

Ok the problem is solved. The rear brake assembly was slightly out of allignment and the brake pad touched the disc. Thats what caused the grinding sound.

Ty for your help Townsends :thumbup:

p.s. will make a new toppic about my 2bros instalment when I heve the time. All went well and the sound that those baby's make is totally :cheer: