|
Author |
Message |
R1stu |
This post is not being displayed .
|
R1stu Shrek!
Joined: 12 Mar 2003 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
jaffa90 |
This post is not being displayed .
|
jaffa90 World Chat Champion
Joined: 06 Apr 2016 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
nowhere.elysium |
This post is not being displayed .
|
nowhere.elysium The Pork Lord
Joined: 02 Mar 2009 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
skatefreak |
This post is not being displayed .
|
skatefreak World Chat Champion
Joined: 06 Feb 2010 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
R1stu |
This post is not being displayed .
|
R1stu Shrek!
Joined: 12 Mar 2003 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Riejufixing |
This post is not being displayed .
|
Riejufixing World Chat Champion
Joined: 24 Jun 2018 Karma :
|
Posted: 15:26 - 17 Aug 2018 Post subject: Re: Can these discs be saved? |
|
|
What's supposed to be the matter with them? |
|
Back to top |
|
You must be logged in to rate posts |
|
|
RhynoCZ |
This post is not being displayed .
|
RhynoCZ Super Spammer
Joined: 09 Mar 2012 Karma :
|
Posted: 15:28 - 17 Aug 2018 Post subject: |
|
|
Perfectly alright, check the thickness. ____________________ '87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor |
|
Back to top |
|
You must be logged in to rate posts |
|
|
pepperami |
This post is not being displayed .
|
pepperami Super Spammer
Joined: 17 Jan 2010 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
MCN |
This post is not being displayed .
|
MCN Super Spammer
Joined: 22 Jul 2015 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
R1stu |
This post is not being displayed .
|
R1stu Shrek!
Joined: 12 Mar 2003 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Teflon-Mike |
This post is not being displayed .
|
Teflon-Mike tl;dr
Joined: 01 Jun 2010 Karma :
|
Posted: 16:45 - 17 Aug 2018 Post subject: |
|
|
What are they off/for?
If they are stainless discs..... to be that bad, then they are probably shot.
If they aren't stainless... Grimeca/Brembo wop-fitment, Morini/Guzzi/Ducati etc.... they look pretty normal.... Er-Nibs Italian Tractor's rotors don't look much different the morning after she'd had a solvol binge!!!!
Two things that would be on my mind are thickness and warpage; then if re-fitted to bike, the pads.
Used to be more common on older race-bikes to 'upgrade' stainless rotors to cast; Pads for stainless rotors are softer, because the metal isn't; so using soft pads for stainless discs on cast would see the brakes very grabby and chewed up in short time.
Going the other way, and using harder pads for cast discs on stainless discs would result in wooden brakes, and rider applying gross lever pressure to get some effect, and often the discs warping and getting scored.
Was most often observed on things like air-cooled RD's and stuff with folk mixing and matching TZ race bits, and the common one of 'upgrading' wire wheels for cast, but keeping the wires to mount 'wets', whilst slicks or race tyres fitted to the mags; but leaving whatever discs were on the wheels, so that the discs got mis-matched when swapped. ____________________ My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
|
Back to top |
|
You must be logged in to rate posts |
|
|
sickpup |
This post is not being displayed .
|
sickpup Old Timer
Joined: 21 Apr 2004 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Riejufixing |
This post is not being displayed .
|
Riejufixing World Chat Champion
Joined: 24 Jun 2018 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
pepperami |
This post is not being displayed .
|
pepperami Super Spammer
Joined: 17 Jan 2010 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Pete. |
This post is not being displayed .
|
Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
|
Posted: 20:17 - 17 Aug 2018 Post subject: |
|
|
Buy 1/2 a kg of citric acid crystals off ebay. Fill bucket with boiling water, dissolve as much of the citric as possible and dunk the discs in for a couple of hours. All the rust will be gone leaving a black film which will wipe right off.
Citric acid is totally safe (it's a food additive) and non-toxic so pour it down the drain when you're done.
Done this week: two small lathe chucks 90 minutes in a bucket of hot citric acid solution. Here's the before and after pics. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good |
|
Back to top |
|
You must be logged in to rate posts |
|
|
RhynoCZ |
This post is not being displayed .
|
RhynoCZ Super Spammer
Joined: 09 Mar 2012 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Riejufixing |
This post is not being displayed .
|
Riejufixing World Chat Champion
Joined: 24 Jun 2018 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
R1stu |
This post is not being displayed .
|
R1stu Shrek!
Joined: 12 Mar 2003 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
R1stu |
This post is not being displayed .
|
R1stu Shrek!
Joined: 12 Mar 2003 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Riejufixing |
This post is not being displayed .
|
Riejufixing World Chat Champion
Joined: 24 Jun 2018 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
MCN |
This post is not being displayed .
|
MCN Super Spammer
Joined: 22 Jul 2015 Karma :
|
Posted: 17:52 - 20 Aug 2018 Post subject: |
|
|
Those discs are not new. They are 'other' discs.
They have been 'cleaned' using Scotchbrite pad or similar.
I can see from the way the very shiny areas around any of the holes.
Those pads are shit for machined surfaces. I would not use on a brake disc. I would prefer a lathe, milling machine or a surface grinder.
The issue with Scotchbrite pads is that the abrasive doesn't move in a single direction. It dips into holes and is lifted up by the edges. That wears any of the edges in the path of the abrasive.
We stopped using them to clean off cylinder blocks, heads and spacer plates due to sealing issues.
A flat plate sander would do the job better. As the abrasive is supported properly.
Work up the grades to get to the finish. There is a correct grade of abrasive to use to 'condition' a brake disc so you don't break it.
The pitting is probably just the casting process. Maybe not a high quality foundry cast them and the pour was not pure.
https://www.youtube.com/watch?v=lM_Ravhnn3s ____________________ Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.
Last edited by MCN on 18:00 - 20 Aug 2018; edited 1 time in total |
|
Back to top |
|
You must be logged in to rate posts |
|
|
stinkwheel |
This post is not being displayed .
|
stinkwheel Bovine Proctologist
Joined: 12 Jul 2004 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
tom_e |
This post is not being displayed .
|
tom_e Brolly Dolly
Joined: 27 Feb 2016 Karma :
|
Posted: 19:14 - 20 Aug 2018 Post subject: |
|
|
MCN wrote: |
Those discs are not new. They are 'other' discs.
They have been 'cleaned' using Scotchbrite pad or similar.
I can see from the way the very shiny areas around any of the holes.
Those pads are shit for machined surfaces. I would not use on a brake disc. I would prefer a lathe, milling machine or a surface grinder.
The issue with Scotchbrite pads is that the abrasive doesn't move in a single direction. It dips into holes and is lifted up by the edges. That wears any of the edges in the path of the abrasive.
We stopped using them to clean off cylinder blocks, heads and spacer plates due to sealing issues.
A flat plate sander would do the job better. As the abrasive is supported properly.
Work up the grades to get to the finish. There is a correct grade of abrasive to use to 'condition' a brake disc so you don't break it.
The pitting is probably just the casting process. Maybe not a high quality foundry cast them and the pour was not pure.
https://www.youtube.com/watch?v=lM_Ravhnn3s |
Those discs are not the new ones he bought but the ones from the first post. |
|
Back to top |
|
You must be logged in to rate posts |
|
|
Old Thread Alert!
The last post was made 5 years, 250 days ago. Instead of replying here, would creating a new thread be more useful? |
|
|
|