Bike making strange whining sound...

[mrtee]

Hi,

My DRZ400s started making a loud whining sound yesterday on the way to work. I can describe it as similair to the sound that a tyre makes when it is flat and you ride on it at a reasonable speed.

I have checked the tyres and they are fine, chain alignment looks ok, chain slack looks ok, nothing obvious seems to be fouling anything.

The noise is present in gear, with the clutch in, and in neutral. It is most obvious at 40mph but I beleive is present at most speeds. (above 40mph wind noise makes it hard to hear and hte noise tails off significantly when you slow below 30mph).

What can I check to try and locate the noise? Could it be a knackered primary drive? front sprocket doesnt appear loose, I ahvent overtightened the chain, the only thing I did to the bike recently was remove and refit the rear wheel.

Rear wheel appears to be in ok though, its a job Ive done hundreds of times without a problem so dont think it can be that.

Could it be the speedo drive making the strange whining noise?

[Turbophein]

my front brakes make a cool whining sound when being used, check that then mark it off the things it could be if its not the same noise.

[mrtee]

happens when you arent braking and is much louder than brake related usage noise.

[HIX]

does the noise change when you drag the rear brake? What about if you slightly get on and off the throttle while keeping roughly the same speed? Since the only thing you did was remove and replace the rear wheel I would guess that the obvious cause would be something is misaligned. rear beake pads would be my first guess, but who knows. I would pull the rear wheel check everething over to make sure it's clean and refit. Might just get lucky and have the noise go away.

[Jaketinaboxer]

is it an rpm related noise or a speed related noise? For instance if you have the bike in neutral and give it some throttle is the noise louder or the same? Is the noise the same at all speeds?

[bink98xcab]

probably the speedo drive, i didnt notice mine til the other day.

[mrtee]

does the noise change when you drag the rear brake? What about if you slightly get on and off the throttle while keeping roughly the same speed? Since the only thing you did was remove and replace the rear wheel I would guess that the obvious cause would be something is misaligned. rear beake pads would be my first guess, but who knows. I would pull the rear wheel check everething over to make sure it's clean and refit. Might just get lucky and have the noise go away.

Im pretty sure its all aligned perfectly. noise doesnt change when dragging the brake. slight throttle changes doesnt affect it.

[mrtee]

is it an rpm related noise or a speed related noise? For instance if you have the bike in neutral and give it some throttle is the noise louder or the same? Is the noise the same at all speeds?

Noise changes at different speeds, is most prevalent between 30 and 40mph.

noise is independant of throttle revving.

[mrtee]

probably the speedo drive, i didnt notice mine til the other day.

IS yours a very loud noise?

[HIX]

Well just being a simple hack my thought process would be this:

No noise

Pulled and did something to the rear wheel

Replaced rear wheel

Bike now has a road speed dependent loud whirring noise that is not affected by load or engine rpm

Action Item:

Pull the rear wheel, recheck everything, replace rear wheel, hope noise goes away.

Why chase your tail when the most likely cause is so apparent given the series of event? If you hear hoof beats dont think zebra, its probably just a horse