Brake rotors

[Shin-Ken 1074]

I'll mic them up and let you know the disc spec. They were smooth to operate before the skim so they were not really in need I just had it done while the front end was apart. Using EBC pads, get around 30,000 km a set, cheers.

[Nessism]

The front disc on my 550E was warped or damaged in some way - pulsation could be felt in the brake lever. Tried to measure runout on the bike but there was way too much slop in the system to get a decent reading. Removed the disc and measured it while laying on a surface plate - something like 0.008" deviation (can't remember). The service limit is 0.012" which is completely crazy, the judder would put you on your ear at that point. Wound up buying a used rotor off ebay for $30 shipped and the new/used one measured at 0.002" and is running great. Suzuki's spec is a little wonky so keep this in mind.

Not sure what this has to do the the original question in this thread but thought like sharing.

BTW, thickness variation is a real enemy of discs with wear. You need to measure the thickness all around the disc in multipul places to get a handle on that. And contrary to what the article states, heat warping often leads to high spots on the disc...which then leads to thickness variation as the disc wears (not caused by deposits in many (most) cases.

[srsupertrap]

Re: posplayr questions

Any idea how much he took off of your disks? I just went an measured all of my bikes and it seems like i could do some surfacing to my spares bike, but they are all already slotted so I guess i dont need to go there.

The front spec appears to be 0.200 +/0.008 with a service limit of 0.180
and the rear is 0.260 +/- 008 with a service limit at 0.240
My fronts(L/R) and rear are :

81 GS750EX 0.182/0.192 and 0.237 (daily rider)
80 GS750EZ 0.198/0.200 and 0.258 (parts bike)
83 GS1100ED 0.192/0.187 and 0.270 (weekend road bike)

Looks like my plan is to remove the GS750EZ rotors which only have 30K Texas hiway miles and get them turned for my GS1100ED.

Swap the GS1100ED frnt left and rear tor the same on the GS750EX. I'm not too worried about the 750 as I only commute in town on side streets.

I would basically be getting ride of the GS750EX frnt left and rear.

Posplayr

I cannot recall exactly how much they removed but it was well within the Service limit. I had the rotors shipped to my place of work and I checked the parallelism with a dial indicator and I believe the max reading was .0005" which is quite good.

Inspection terms are often used interchangeably. Flatness is a measurement to itself which is identified with a datum. Parallelism measures another surface relative to the datum. So if you take a brake rotor and place it on the inspection plate and sweep the side facing you (up) with a dial indicator you have measured the parallelism. To measure flatness the rotor would be placed on equally spaced 1-2-3 Inspection Blocks and then swept from the bottom with a dial indicator. I would agree with the previous suggestions the best functional check is to mic your rotor.

Again, this service was an excellent solution for me because my rotors were already cross drilled and I didn't want to toss them.