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View Full Version : a couple questions on the front rotor and clutch pull issues



buell-fan
07-19-2015, 09:37 PM
So I am looking at a couple different RX's with similar build dates but different vin#'s and need to know how to tell if the East Troy factory put on the new rotors that corrected the manufacturing defect in the surface grind or if the original lots are on there that had the bad surface, causing the braking issues. Please describe to difference in the two or, if there is pictures someone can post of what the bad rotor looks like to compare to the new version that would be great.

Also, the factory updated the clutch master cylinder to make the clutch pull easier from what I understand. Does anyone know what they did to it exactly, to make it better? Is there a way to tell if the bikes I am looking at have that upgrade also?

mackja
07-20-2015, 10:17 AM
I don't know how many units had the bad rotors, I had one and you could tell almost immediately because of the vibration felt under braking. The clutch update was done late and not necessarily the best option, clutch pull is not that bad under operation, some have reported that under hard acceleration the updated clutch would slip some, I have left mine alone, if I do anything it will be to install a Brembo rcs master cylinder or Accossato unit. So far I have had no problem living with the stock clutch.

buell-fan
07-20-2015, 11:39 AM
After further investigation on the clutch fix, I wouldn't put weaker springs in it either. I would rework the master cylinder to push more fluid easier.

As far as the brake rotors go, were they warpy looking with high and low spots around them or anything like that? From the limited pictures I could find it looks like some bikes have rotors with intermitent dark and light spots on them where the pads would leave residue on there. I would like to get a good set with the bike since we don't know how the warranty will pan out after the auction sale coming up.

mackja
07-20-2015, 03:06 PM
The issue was with the supplier and how they finished the rotor, two different grindings on the surface resulted in a pulsating, nothing to do with heat.

buell-fan
07-20-2015, 09:56 PM
The issue was with the supplier and how they finished the rotor, two different grindings on the surface resulted in a pulsating, nothing to do with heat.

Could you post a pic of one or the other, good or bad, so I know what to look for. Thanks.

mackja
07-21-2015, 06:09 AM
Visually you cannot see any difference, you have to ride one to find out.

buell-fan
07-21-2015, 05:50 PM
Visually you cannot see any difference, you have to ride one to find out.

Is that something that shows up immediately, or after the brakes bed into the rotors?

mackja
07-21-2015, 05:59 PM
I really don't recall when the pulsating started, wish I could be of more help, maybe a few others on the forum can provide further information.

buell-fan
07-21-2015, 10:38 PM
I really don't recall when the pulsating started, wish I could be of more help, maybe a few others on the forum can provide further information.

Thanks for the input. It sounds as though the rotors hit and miss on the pulsing issue with the first production bikes. I will take my chances on them.

snacktoast
07-24-2015, 10:54 PM
Is that something that shows up immediately, or after the brakes bed into the rotors?

If the rotor has issues related to the grinding finish from the rotor manufacturer, you will typically feel it right away.
Cosmetic appearance does not dictate or necessitate replacement. It's a feel thing.

buell-fan
07-24-2015, 10:58 PM
Does anyone know whether the EBR rotors are the same bolt pattern and size as the Buell 1125CR?

snacktoast
07-24-2015, 11:02 PM
Bolt pattern - yes, so the rotor is interchangeable from the 1190 to 1125.
However, the mounting hardware is different on the 1190 compared to the 1125.

buell-fan
07-24-2015, 11:13 PM
Bolt pattern - yes, so the rotor is interchangeable from the 1190 to 1125.
However, the mounting hardware is different on the 1190 compared to the 1125.

Thanks. They looked similar.

Mike
07-30-2015, 09:34 PM
On the rotor...actually, after a few miles, you "can" see the problem.
It's variously sized shiny spots. It's from overheating the metal. The bright spots are "now" harder than the surrounding metal. I wouldn't be happening if the caliper pistons would retract a little more.
I've never had a bike except my 1125CR (actually wasn't as bad!), where the disc was way too hot after my drive to work at 4:30 in the morning. My R1 Yamaha, my S1000RR BMW and all other past bikes, you could grab the front rotor after my 41 mile drive. NOT this bike. The RX's rotor is MUCH hotter than most all of my other bike after the same distance.

I even over heated a set of rotors (long story) years ago to the point of VERY bad fade. NO heat "checks".
My RX's rotor...is full of them after only 55+ hundred miles. The only good (odd!) thing, is I can't feel them yet in the brake handle..!?

This not a guess or myth. I need to know a bit of metallurgy for work.

Hoping they don't get to the point of feeling them in the handle.

Mike

buell-fan
07-31-2015, 12:45 AM
Thanks Mike. I did figure you could see the well used bad rotors, as there are several pictures on line of bikes with shiny spots on them. I was hoping to learn how to spot a new rotor with the bad grind pattern or whstever was done wrong by the manufacturer.

As for the rotors getting hot, I suspect that the problem is because of brake pad drag. Most calipers have a stationary side where that pad just "rides" somewhat loosely on the rotor. If one side of the EBR caliper is constantly rubbing tightly to the rotor then they are building excess heat that is effecting their performance.

A simple experiment would be to run the bike for a lengthy ride using mostly, if not all back brakes, to make your stops. Then feel the rotor to see if they are hot. If the caliper is rubbing too hard on the rotor it will definately be hot, just as if you had been using them all along the ride. One would think that with all that swept area of the Buell rotor they should naturally be a bit cooler than a hub mounted rotor based on physics.

Betterbuell
07-31-2015, 07:59 AM
Not thinking to hard here, couple of beers, but not only have we 4 pads working on one rotor (even though the circumference is bigger) , but the rotor is also travelling faster for the same wheel speed . Its going to get hotter. Imagine how hot my track bike rotor gets , its blue !
Wonder if anyone makes a carbon rotor? Would be cool . Group purchase order ?