Rear brake rub question?

[ronsonol]

Model year 2004.

I've perused a few of the previous threads regarding the rear brake rubbing against the disk.

I actually adjusted the chain tension (the chain was literally able to slap against the swingarm) and I am not sure if this sort of brake rubbing is ok. I've read that it the rear will rub slightly, but that seems subjective to me as I don't know what it sounded like before I adjusted the chain.

To be fair when rotating the wheel it does do one full rotation.
[ame="http://www.youtube.com/watch?v=gjom8OxDHeM"]Here is a video [/ame]

Also while on the topic, after adjusting the chain, I noticed that the RPMs ran higher than normal compared to road speed (for example in 3rd gear 40mph with 5k rpm, compared to 4k when chain was looser) and I'm not sure if its because of the chain adjustment, or the rear brake rubbing.

I can also hear the rear wheel hum while riding, as if the brake was rubbing against the disk. It feels ride-able but of course I'm super self conscious and it is my daily driver.

 

[iSteve]

That isn't that bad, remember beside some brake rub you are also moving the chain. But if after you adjusted your chain you didn't get the same alinement the brake disk could be hitting the pads ends a little.

Also there really is no way that RPM vs MPH can change unless you have a seriously bad clutch.

 

[ronsonol]

After riding a bit today, I realized that the humming noise resembled when tire hit pavement.

While on the center stand, the rear wheel appears to be aligned, and when I pushed the pads off the disk and spun the wheel it still made that sound as if the brakes were rubbing, but it couldn't have since they were pushed off the disk.

Riding on the street seemed normal with the occasional burnt oil smell (I had accidentally dropped some engine oil on the pipe during oil change).

Thanks for the quick reply iSteve

 

[KingY]

Whats the age and condition of your tyre? and same for chain and sprocket?

Also is the tyre inflated to correct psi?

Possible bearings if all these things above check out?

 

[TownsendsFJR1300]

As posted above, the rear brake doesn't appear to be an issue.

To easily double check it, go for a 10-15 minute ride (30-50 MPH). Stop immediatly with JUST THE FRONT brakes. Now, carefully, feel the rear rotor. *(You can also do the same for the front brakes, just use the rear brake)*

It should be cold to very cool. If its hot or very warm, it needs attention. That may be just lubing the slider pins or a caliper re-build (but yours sounded fine).

As for the chain, yours did sound somewhat dry (or just noisy).

With the bike on the centerstand, take a tape measure, and at the taughtest point of the chain, on the lower run, near the black plastic swing arm gaurd, measure the TOTAL MOVEMENT, up and down of ONE PIN.

It should be between 1.75" and 2". And yes, it'll be very close to the lower swing arm, that's why there's a gaurd.

A clean and lubed chain will give you the mist accurate measurement...

 

[odachi13]

It could be just a simple build up of break dust and dirt.

Run hot soapy water over your disc, on both sides, and keep spinning it. You will probably notice the problem gets worse - simply because the dirt is crystallizing and expanding with the heat, then simply rinse off with a hose down the caliper (never a pressure washer).

Dry the brake by spinning the wheel then stopping it with the brake a few times to clear the piston.

 

[ronsonol]

Solved: Rear brake rub question?

@KingY: The condition of the tires seem fine, lots of tread still, and correct PSI. The age of the tire, chain, and sprocket are all stock from 2004.

@TownsendFJR1300: The rear rotor appeared to be cool to the touch so I assume the brake isn't an issue. I did add additional chain lube, but it still runs just as noisy. I adjusted the chain as you said and that has actually eliminated the humming altogether (to be fair I also made sure the alignment was proper as well). I'm not sure if it was the taughtest point but I tried to the best of my judgement, I didn't realize it was supposed to be that close to the swingarm.

 

[TownsendsFJR1300]

Re: Solved: Rear brake rub question?

@KingY: The condition of the tires seem fine, lots of tread still, and correct PSI. The age of the tire, chain, and sprocket are all stock from 2004.

@TownsendFJR1300: The rear rotor appeared to be cool to the touch so I assume the brake isn't an issue. I did add additional chain lube, but it still runs just as noisy. I adjusted the chain as you said and that has actually eliminated the humming altogether (to be fair I also made sure the alignment was proper as well). I'm not sure if it was the taughtest point but I tried to the best of my judgement, I didn't realize it was supposed to be that close to the swingarm.

Sounds like your good now.. :thumbup:

Yep, the FZ has about the longest chain tension (while on the centerstand) of any bike I've seen/worked on. The chain, as it wears over time/mileage, will start making more noise, slowly, but surely. Kinked links thats don't straighten out anymore will also make some vibration. Keep an eye for any links as such, its telling you its time for replacement.. Depending on how tight the chain was initially, is probably what I was hearing. Too tight, more noise, like a guitar string. **BTW, the chain gets tighter once on the ground as the swing arm levels out pulling the chain tighter..

What I do to find the taughtest point of the chain is lay on the floor and put a tape measure adjacent to the chain pins. The rotate the wheel slowly, watching to see which pin rises the most. I do this check in the area of where I'm actually going to check the free play. Once you have that pin located, adjust accordingly.

 

[tosh23]

Looking and listening to the video I would say its the chain alignment, that sounds like its way way out