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smooyhrider215
09-06-2011, 11:53 AM
Cant believe this happened! Went for a ride bike felt funny then i felt bike slowing down and realized rear brake was dragging, pulled over and then the braided line burst @ caliper/crimped fitting location, spayed out onto exhaust and was on fire! what the fuck is up with this? this bike has been great up till this and I ride with my toes on the pegs so i was not dragging the brakes. I am replacing the brake line and not bothering with the wires for the brake light. rotor does not seam to be warped so I will soon fig out how to bleed the rear i guess. please let me know if you have experienced this

Brucetafer
09-06-2011, 01:54 PM
sounds like the master was adjusted wrong or was not fully retracted.. its happened on many bikes... were you doing anything out of the ordinary or have the brakes messed with at all?????

Chris_Mag
09-06-2011, 02:40 PM
Dot 4 brake fluid has a flash point of 248 degress F. Was it smoking or was there visable flame?

Antihero
09-06-2011, 04:13 PM
In all of my experience, there are two things that cause a brake line to burst. The most common is that someone removes the caliper and lets it hang there while performing a brake job, etc. Calipers on bikes are really not quite heavy enough to cause damage to a fitting/line and I can't imagine you - or your dealer - ever removed the caliper, which leads to the second cause--the manufacturer of the brake line. Hmm, I suppose a factory monkey could have screwed it up while the bike was being assembled. I'm not sure who to contact, but you and/or your dealer really should have someone investigate the nature of what caused it. Fortunately it was the rear and not the front!

Bleed can be done a couple ways. Easiest way would be to get a suction gun and secure it to a nipple. Fill the reservoir and then suck away, making sure the res is always full. You could also do it with the 'gravity' method, filling the res, then letting gravity take the fluid down. Once fluid comes out of the caliper, tighten the nipple, then pump the brake lever a few times. Holding the lever down, crack the screw until fluid/bubbles appear. Tighten and repeat until no bubbles.

Rspec99
09-06-2011, 05:00 PM
That sounds like a terrible experience, but it seems obvious that the rear brake was dragging or binding. However, this is something that probably could have been avoided with regular pre-ride inspections. After every ride (or every second ride), I will often check critical systems such as the brakes, chain, sprockets, tire pressure, and suspension. Simply putting the bike on the stand and spinning the wheels to make sure there is little drag on the brakes and that the chain is clean and sprockets are in good shape, and that there is no tire damage can go a long way to saving yourself from a potentially dangerous situation.

Anyhow, obviously this is something that shouldn't have happened, but hopefully it will help serve a reminder to all of us to check our bikes regularly.

Antihero
09-06-2011, 06:03 PM
If the brakes were really overheating/dragging/binding and the fluid heated to the point where the PSI increased to a dangerous point, fluid should shoot out of the plastic cap / reservoir before blowing a a stainless steel line apart.

Diablo1
09-06-2011, 07:07 PM
I'll guess it's the fault of the last one to fill (over-fill) the brake fluid reservoir, or adjust (mis-adjust) the free play in the brake pedal.

pete roper
09-06-2011, 08:02 PM
The problem is almost certainly down to a poorly adjusted actuator rod between the master cylinder and the brake lever. If this is adjusted so there is insufficient travel for the piston in the master cylinder to fully extend when the brake is not applied the piston will obscure the bleed back hole that allows not only for the system to prime as the pads wear but also to allow fluid to return to the reservoir when the brake is released. If it can't do this the brake effectively becomes a 'Closed' system. Brakes work by changing the kinetic energy of the bike and its rider travelling along into heat. Some of this heat will be in the disc and will be dissipated by radiation, conduction and convection to the aie and the wheel but some of it will be transfered to the pads and thence the caliper. As the caliper heats the fluid will expand. If it can't bleed back to the reservoir the only thing it can do is 'Move' the next moveable bit which will be the pistons in the caliper. This will push the pads onto the disc creating more heat and the whole thing becomes a viscious cycle.

On most bikes the dragging rear brake will become immediately apparent. with something as powerful as an RSV-4 though its quite likely that it will be overlooked as the rider, not suspecting anything is wrong, may simply keep opening the throttle and overwhelming the brake. On a long, sraight boring road I can see that happening but if you were pushing on in the twisties it should become immediately apparent as soon as you hop off the gas! Most likely the rear wheel would lock up!

The rear brake is a pretty useless stopping device. it's main purpose is to settle the bike approaching corners and to allow you to steer when you're in them. Because I don't ride hard much any more I rarely use the back brake! I think I've got the original pads in the back of the Griso and its done 50,000kms!!!:D

Before you simply replace the brake line? Check and adjust your actuator rod and pedal position for the barke and, btw, I'd be VERY surprised if the disc wasn't scrap!

Pete

smooyhrider215
09-07-2011, 07:17 AM
Guys,

Thanks for all the insight I will be sure to check these things to ensure this does not happen again. I will post in a days or so when i am putting on new line and let you all know my findings.

Thanks again

smooyhrider215
09-13-2011, 09:33 PM
new brake line and pads showed up today! I adjusted pedal a little bit and bleed the caliper, what a bitch!!!! about 40 min but now its done. I also checked rotor with caliper bolt ran in just rubbing and it seamed to be fine. not sure why this happened but all is good now.

leeschmidt
09-13-2011, 10:00 PM
just to let you know my brake pivot bolt backed out on mine causing the brake to drag, i caught it in time as not to do any damage

zvez
09-14-2011, 01:28 PM
Are you talking about the brake pivot bolt on the caliper?

Chris


just to let you know my brake pivot bolt backed out on mine causing the brake to drag, i caught it in time as not to do any damage

leeschmidt
09-15-2011, 11:57 AM
Are you talking about the brake pivot bolt on the caliper?

Chris

yes that is correct

zvez
09-18-2011, 12:24 PM
thanks!


yes that is correct