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Post by Diego the toe clipper on Apr 4, 2019 16:06:20 GMT
So I've got a dilema.
My GSXR 20th Anniversary has always had a lights judder under braking at higher speeds, and a noticeable pulsing of braking grip under light braking at low speed, as if there was an area of a disc thicker, or thinner than the rest.
I took the wheel off a while back and cleaned all the crud out of the bobbins and also lightly sanded the rotor surfaces.
That certainly made a difference and I decided to live with it until it was new pads time. That time is now.
New discs from Suzuki are out of the question, and I am loathed to go with pattern discs given that the discs are specific to the 20th Anniversary edition and I'm a bit too OCD.
Now I've seen some discs for sale second hand, seller seems to be reliable and is local to me, but I realise that asking him to let me fit the discs to try them out is frankly taking the piss.
So where would you throw your cash?
Buying used discs on a sold as seen basis, or
Taking the old ones to a engineering shop to see if they can skim them?
Results of skimming semi-floating discs seem to be a bit hit and miss.
Any simple checks I can do on the used discs to have an idea of their condition? Maybe with a steel ruler and feeler gauges?
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Post by mekon on Apr 4, 2019 17:00:50 GMT
Buy the pattern ones in the meantime, keep the originals if you're after that original parts look if you ever sell, maybe get them skimmed at your own pace then, no rush.
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Post by neilf on Apr 5, 2019 8:42:43 GMT
I supposed that it all depends on how much meat there is left on your current discs and what the pad wear is like; take too much off and the discs may warp. If you have the budget, personally, I'd go for new discs and pads. When my 750K1 needed replacement discs, I went for ECB Pro-lite discs and Carbone Lorraine SBK5 sintered pads. With standard hoses and fresh fluid, the stopping power and feel improved massively; when I fitted Goodrich Braided Hoses, it was like hitting a brick wall. Following that I had the front forks serviced and, as such, I needed to up the compression to compensate  |
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Post by mekon on Apr 5, 2019 9:54:06 GMT
My VFR brakes are like hidding a childs inflatable punch bag. I don't think the suspension would take brick wall levels of stopping anyway.
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Post by Droog on Apr 6, 2019 14:30:31 GMT
I would not bother with the skim. Motorcycle discs are just too thin to begin with to avoid warping.
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Post by pantah on Apr 6, 2019 19:32:05 GMT
If the OCD can’t be cured and the used ones are local, maybe the seller would let you buy them on approval. A local machine shop or a college workshop could easily check if they are true by placing flange face on a surface table and slide a clock gauge over the disc surface to check flatness. A micrometer to check uniform thickness would confirm that the inside face is ok. Any more than 0.05mm and I wouldn’t use.
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Post by Diego the toe clipper on Apr 8, 2019 16:06:53 GMT
OCD cannot be cured...
I'm off to look at the used discs later this week, gonna take a digital caliper, straight edge and feeler gauges. Seems to be about all I can do without fitting them and spinning them. The seller reckons they came off a bike with 20,000 kms.
Have to say that I agree with Droog about the skimming option. My bike now has 70,000 kms on it so skimming those discs is likely to be waste of money.
Engineering to Joe Public here is quite expensive as punters don't repair their own stuff. I asked a good machine shop that I trust for a quote and (without seeing them)they quoted me the exact same price as the guy with the used discs is asking.
Between gambling on skimming my old discs and gambling the same cash on some used discs, I'm tending towards the used disc option, unless my preliminary checks show up some dodginess.
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Post by Diego the toe clipper on Apr 13, 2019 8:55:11 GMT
I appear to be suffering from Mekonitis...
Went to take some some measurements of my discs yesterday to compare them with the used ones up for sale, and noticed the bottom of my right fork leg is drenched in oil. Fork seal totally blown.
The good news is the discs for sale locally are noticeably thicker than mine using a caliper, and have much less surface variation. The guy was also a good proper biker type who insisted that if I had any problem he'd refund the money.
Now I just have to get the fork seals done...
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Post by pantah on Apr 13, 2019 15:30:02 GMT
I have some white heather available if Clipper, Mekon, or Droog are interested. 😊
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Post by Diego the toe clipper on Apr 25, 2019 10:40:07 GMT
I'll have some white heather please....
Oh the joys of working on an old sports bike... now I've discovered that the one of the fork legs is damaged. It seems to have received a whack at some point and the casting at the bottom is missing one of the lugs where the mudguard bolts on.
The fork may well be straight, haven't checked it yet, but as I hate re-using parts which I know to be damaged I've been looking for a replacement right fork.This time though it seems that luck is on my side because I've found someone selling a brand new right side fork stanchion still in its packaging for 60€, but the bastard is on holiday till 6th May. Bastard. At least he says he´ll sell it to me when he gets back!
So my disc change is now turning into a full front suspension rebuild...
I just hope that when I take the left fork apart, that isn't damaged also...
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Post by pantah on Apr 26, 2019 6:40:58 GMT
Sorry Clipper.
A Raven stole the white heather
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