Whining noise from front at some speeds, brake issues. Wheel bearings?

[Junkie]

Went to leave for a trip and a couple hundred miles in, after a decent downhill section, I stopped to take a few pictures. I get back on the bike after several minutes, continue, get to the next corner and have next to no front brake. They pump up after a few tries, go away a little again, and then seem ok for the rest of the day (although I didn't work the brakes as hard after that - 2500ft in 5mi is fairly steep, 10% grade).

I later noticed a whining noise from the front, at certain speeds.

Am I likely experiencing a failing front wheel bearing, or just being paranoid? Prior to yesterday I had put several hundred miles on the Shinko 705s and wasn't noticing any noise.

 

[1wiseguy2]

Went to leave for a trip and a couple hundred miles in, after a decent downhill section, I stopped to take a few pictures. I get back on the bike after several minutes, continue, get to the next corner and have next to no front brake. They pump up after a few tries, go away a little again, and then seem ok for the rest of the day (although I didn't work the brakes as hard after that - 2500ft in 5mi is fairly steep, 10% grade).

I later noticed a whining noise from the front, at certain speeds.

Am I likely experiencing a failing front wheel bearing, or just being paranoid? Prior to yesterday I had put several hundred miles on the Shinko 705s and wasn't noticing any noise.

Could be moisture in your brake fluid. If they got hot the moisture will flash to steam/vapor and pumping it a couple of times will compress it... same as air. So, how old is your brake fluid? The whining...I haven't a clue. Can you put your bike up on a centerstand and spin the wheel and see what happens?

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[Junkie]

I flushed the brakes after I bought it early this year, so it's fairly fresh. Doesn't look bad either.

Haven't put it up in the air to check things yet.

 

[1wiseguy2]

Might try to just see if there might be air in your front brake. Try to eliminate the fading problem. Still on your trip?

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[Junkie]

No, given that I'm concerned it could be bearings I headed home. I was thinking that bad bearings could result in some wiggle in the rotor and therefore pushing the pistons back in - I've had that happen with bent rotors before.

Brakes worked fine for the rest of the day so I doubt it's air.

Forgot to mention, 45k on it.

 

[1wiseguy2]

No, given that I'm concerned it could be bearings I headed home. I was thinking that bad bearings could result in some wiggle in the rotor and therefore pushing the pistons back in - I've had that happen with bent rotors before.

Brakes worked fine for the rest of the day so I doubt it's air.

Forgot to mention, 45k on it.

Could be bearings then.

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[dduelin]

This is a strange set of events. Wheel bearings aren't going to create a problem as described then get better as described and an overheated brake should have cooled while you took pictures, and would have been noticed when you stopped to take pictures because it was still hot. I think I would immediately flush out and replace the brake fluid with quality DOT 4. Maybe a previous owner used the wrong type. The wheel bearings are easily checked - if you have a center stand or jack the front off the ground. But I think they will check out OK.

 

[Red Rider]

I would chalk up the whine at certain speeds to the tires as they are wearing. That sound will likely change and ebb and flow as you add miles to them. Pretty normal to hear over time. IMHO

 

[MZ5]

I agree that this is a very strange series of events. The whining is probably the lowest priority item to chase of all those mentioned in the thread. Bleed or flush & bleed the brakes, is my suggestion. Then go from there.

 

[Smallville]

Just a guess here, but I’m thinking your brakes were fairly warm when you stopped. The fluid had expanded and sent some back to the master cylinder. After cooling there was a void to fill by pumping the fluid back. It’s a complete guess.

 

[Junkie]

I've never had that happen on track/when racing. It's something I thought of, I'm just curious as to why I haven't encountered it before.

I'm sure the brakes were reasonably warm, but they weren't exceedingly hot or anything.

 

[Deleted member 1183]

I have had the pistons pushing back on my former KTM Adventure and require pumping as a result, but only after riding quickly over extremely rough ground offroad. I admit that the requirement to pump accompanied by whining would have one thinking bearings, but if it was bearings then the pumping would continue to be required. My only other suggestion with regard to the whining would be tyre noise as suggested already above.

 

[Junkie]

I've had pistons pushed back due to a tankslapper, I can see it happening over very rough roads, but this was a paved road in decent shape.

I was also surprised that the brake problems went away, I'd expected them to continue.

 

[youkiddin]

the noise you noticed is most likely the 705 on the front, I hear it all the time from the front on mine as the bike leans off the center of the tire.

 

[Rapturee]

Hey Junkie, what did you find when you placed the NC on it's center stand and checked everything out?? :{)

 

[Junkie]

My centerstand isn't tall enough, and I don't think I have enough weight on the rear to get the front up on the stand either.

Haven't gotten around to doing anything.