[banhmi]

My V650 2015 has been eating brake pads (edit: ~2500 miles per set of pads). The first time I didn't catch it in time and it ate through my rotor. The second time I caught it in time and discovered a caliper grease boot on one side had worn through and was dry, while the other side had very little grease (the two rods it slides on). I rebuilt the caliper from ground up, took everything apart, cleaned, replaced piston seals, new grease boots packed with grease, new pads, etc.. Piston was in perfect condition. All looked to be perfect. Now brakes are working fine, however, I noticed the rotor is quite warm/hot to the touch after riding. There is no discoloration, but it's hot. I am not using rear brake excessively. What's strange is the front rotors are cold, even though I'm using the front brake all the time.

I'm thinking for some reason the piston is not retracting, even with brand new seals, but I have no idea why.

Anyone else encountered this and identified a solution? After a complete rebuild I can't think of anything else to do.

 

[fasteddiecopeman]

I BELIEVE my BC V650 ('15 LT) is ALSO doing that to the rear brake pads, but CAN'T check as I'm in AZ now.

 

[banhmi]

I BELIEVE my BC V650 ('15 LT) is ALSO doing that to the rear brake pads, but CAN'T check as I'm in AZ now.

I've seen some posts here that say the brake fluid reservoir might be too full. That has prompted me to do two full pumps bleeding the line from the caliper. Haven't rode it yet, we'll see if that worked.

 

[HAWKSHOT99]

Your brakes are definitely dragging. I have 35k on my rear pads, and they show little wear.
If you lift the rear wheel on a stand can you notice the pads dragging as you turn by hand?

 

[Fly-Sig]

Something is not right. If you've rebuilt the caliper to no improvement then it must be elsewhere. I would guess the brake pedal mechanism somehow. Either the pedal is not fully returning to the un-pressed position or the valving has a problem.

Valving would include the rear ABS module and the master cylinder. I have not messed with these on my bike, so I can't offer any specific ideas other than to disassemble as much as can easily be done and clean them out. When you release the brake pedal, fluid has to return to the reservoir by moving in reverse. Somehow it is not being allowed to return to the reservoir.

Seemingly less likely since you have already rebuilt the caliper is some kind of problem there or with the disc. A warped disc could be the problem but I think you'd feel it and hear it. Or the caliper is not sliding easily on the pins. Or the disc is not in the proper location left-right, which could be the wheel is not properly centered.

If you remove the caliper, try pressing the brake pedal which will extend the piston, then press the piston back in with your hand. I have always been able to do that easily with just hand strength (and I am just an average old guy). This could tell you if there is an obstruction to return of brake fluid to the reservoir.

Another experiment would be to disable the rear ABS module to see if that makes a difference.

I would not take it to the dealer yet, as they will probably just fiddle with it and spend your money, and you can fiddle with it for free.

 

[Fly-Sig]

Also just brainstorming, there could be an obstruction in the hoses. It may allow fluid under high pressure to flow to the caliper but then not allow low pressure to move it back to the reservoir, trapping a little bit of pressure which drags the brake a little bit.

If you had a significant drag of the brake your fuel economy would be terrible and the disc would get really hot. I had a master cylinder on a car fail one time, and in just a few miles the disc was glowing red. It was very impressive at night.

 

[Vernier650]

Some thoughts that come to my mind:
1) Go for a ride and make sure that you do not use the rear brake at all. (remove the lever is you have to) Is it still getting hot?

2) Put it on a stand and see if the wheel is free. Maybe it's a warped rotor which will be touching at certain points and free at others.

3) Maybe it's all just fine! You haven't reported your pads wearing out excessively after the rebuild. The rear brakes do not get nearly as much fresh air as the fronts do so maybe they stay hotter longer.

I rode through a set of pads unknowingly on a different motorcycle cause my boot was on the lever all the time. Only realized it when the fluid started boiling and the lever was bottoming with no resistance. That reminds me I've got some work to do!

 

[banhmi]

I think I've found the problem. In the brake reservoir under the seat there is a rubber boot, like an accordion. It was extended, like a balloon inside the reservoir. I compressed it back into its normal position, kind of ends up with concentric circles and sits much higher up in the reservoir. I think that boot was applying pressure on the brake fluid. It seems to be working fine now. Rotor still gets a little warm, but nothing like it was. Wheel spins freely now when on rear stand and the contact noise I was hearing has completely stopped. I think I'm good unless I see fast wear in the pads again - will monitor it.

 

[fasteddiecopeman]

I BELIEVE my BC V650 ('15 LT) is ALSO doing that to the rear brake pads, but CAN'T check as I'm in AZ now.

An UPDATE:

On my Gen 3 V650 (don't forget that I HAVE a Gen 1 '08 in AZ, and HAD a Gen 1 '09 in BC, written-off at 62,790 kms - 39,016 miles) the rear disc is wearing quite noticeably, and this at 73,013 kms (45,368 miles).

OTOH - the '08 at 92,xxx MILES is still on the OEM rear pads and disc, and I NEVER changed EITHER on the '09. So you can take it from these data that I ride or rode all three in a similar fashion, so SOMETHING IS VERY DIFFERENT in the Gen 3s.

 

[banhmi]

Update - It's only been a month and I can see the rear pads are wearing too fast on the brake piston side. That pad is about 3/4 the size of the other, which is not worn at all. I've barely put any miles on these pads, installed only a month ago. Not sure why one pad is retracting and the other isn't. I did notice that the service manual calls for putting silicone grease on the rings, which I didn't do. I used brake fluid, as seen in every youtube video on rebuilding brake calipers. Getting mighty frustrated with this rear caliper.

Something I just read in the service manual on page 12-23 regarding the rear master cylinder:
- Check that relief port [G] and supply port [H] are not plugged.
* If the relief port becomes plugged, the brake pads will drag on the disc. Blow the ports clean with compressed air.

This might be it, looks like I will be spending some time with the master cylinder soon.

Front calipers work perfectly, almost no wear on the pads ever. However, I know the rotors are warped...minor pulsing at low speed.

 

[fasteddiecopeman]

Good luck!

 

[jaaklucas]

Haven't had that problem on my 15 650. I changed my rear pads at 60,000k although it still had an 1/8th of an inch of pad left. Mind you, I'm not hard on the brakes. I keep that rear disk clean. After every day ride at some point later I spray the chain with Teflon or WD spraycan with the long, thin nozzle and then wipe the rear disk clean with alcohol and paper towels while the wheel is up and spinning. Mainly for brake efficiency but helps squeaking, dragging ,pulsing etc. Then use the "dirty" paper towel to wipe clean the chain spraying overspill. Clean slide pins makes a difference too I would think. Then spin the wheel and marvel at how effortlessly and quietly the drive wheel turns!

 

[banhmi]

Haven't had that problem on my 15 650.

You have been very fortunate. I've been having problems with my rear brakes, front brakes (warped rotors), and stator burned out. The problem with the rear brake caused me to wreck my rear rotor also, because I didn't catch the pads wearing out so fast.

Otherwise I love riding this bike, and I have two others that compete, but the versys always wins. I need to get these brake problems resolved once and for all. My latest attempt on the rear is to adjust the pedal. Just a very slight adjustment to reduce the push rod size. I'm hoping that there was pressure even after releasing the brake and that adjustment will alleviate it. Will watch for a while and if that doesn't change anything, a master cylinder rebuild appears in my future. Perhaps the return spring inside the master cylinder isn't pushing enough. All I can do is guess.

 

[jaaklucas]

and stator burned out

I haven't have a problem with mine. It is underpowered for us in general. I did a Polaris series regulator retrofit at about 50,000K which alot of us have done for precaution. It will help, its a better system than the stock "shunt" system.. LED lighting will also cut the current draw down.

 

[Smiley]

"Something I just read in the service manual on page 12-23 regarding the rear master cylinder:
- Check that relief port [G] and supply port [H] are not plugged.
* If the relief port becomes plugged, the brake pads will drag on the disc. Blow the ports clean with compressed air."

If all else fails, read the manual, or as it's better known, RTFM!

 

[banhmi]

Looks like the pedal adjustment was the magic! Took it out yesterday and felt the rear disk when I got home, not hot at all, barely warm. Woohoo! I also noticed that the bike rolls more freely at stops, so there must have been a small amount of pressure being applied by the pedal return spring against the master cylinder. By reducing the length of the push rod, it alleviated that pressure. And I only adjusted it by about 1/6th of a turn. Just barely turned it!