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Post by chrisbikes on Dec 28, 2005 21:07:22 GMT -5
Seasons' Greetings Every(any)one!
Does anyone have experience with the drilled front disc from MikesXS e-parts? It's the same dia as the stock one - 298mm, and from what I've read from others here, the same thickness, bolt pattern, etc.
My front disc is original and at 37000 kms, fairly scored. It has fairly wooden feel and stopping power is poor when compared to my '83 305 Kawasaki GPz 305, which borders on ferocious! I doubt I could even lock up the front wheel on the SR.
I have got SS braided brake lines which prev temporary owner replaced with original rubber ones. I was going to do both jobs at same time.
Any advice, thoughts? I asked my friendliest mechanic about drilling mine, and he wasn't too keen - and he's a machinist too?!
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Post by miker on Dec 29, 2005 9:36:23 GMT -5
Isn't the standard XS disc thicker?
miker
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Post by miker on Dec 29, 2005 10:26:03 GMT -5
Ok, took calipers and headed for the garage. We know an XS front wheel will bolt right up to the SR, so that means the disc bolt pattern is the same. On my '81 XS the front disc is .275" thick. On my '78 SR the front is .203" thick... fair difference. I would assume the disc at Mikes is made to the XS spec.
There's some good posts on the XS650 Garage on drilling your own, FYI.
miker
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Post by hopwheels on Dec 29, 2005 12:51:30 GMT -5
Hey guys: The bolt pattern for SR and XS rotors is the same. The calipers are essentially the same (other than the left or right hanging bracket). The thickness on XS rotors is different, 6mm roughly to the SR's approx 5mm. Both are 298mm in diameter. As for drilling, I am as complete a novice as they come. Drilling my rotors was one of the easier undertakings on my project bike so far. The XS650 link is great advice, because they passed around a couple of .pdf patterns to print out and use as templates. I started from there and modified mine a little. Just keep the rpm's on your drill press really low (I used 700rpm), titanium bit, clamp the rotor tight, and some cutting oil as needed (I also recommend some tunes and a few beverages to pass the time!). You should be able to have great success. Here's a link to the finished product on mine. Take care. Gary Hopwheels www.hopwheels.com/pics/drilled_rotors.JPGPS: Can anyone add info as to any problems using the thicker XS rotor on an SR? (My entire front end is from an XS so I'm assuming no problems with my build), but can a XS rotor simply be used in place of an SR rotor with no problems? |
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Post by StewRoss on Dec 30, 2005 3:25:18 GMT -5
Hi Gary,
Nice job on the discs. Time consuming job.
The 650 discs should fit so long as they fit between the calipers and pads.
Have you got twin discs fitted with the standard master cylinder? That can give you a vague feeling during braking from my experience.
I used an MC from a Yam (750? triple) or similar that had two discs to begin with. They still had slightly vague feel, however, the lever hardened up and it felt the way it should...
Twin discs on the SR give good braking, much better than one. They can accentuate tank slapping somewhat due to the exra unsprung weight that the heavy calipers and discs provide.
SR
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Post by hopwheels on Dec 30, 2005 12:00:06 GMT -5
Hi Stew: Forgot to mention, hope everyone had a nice Christmas, and happy new year! It did take quite a while to drill those discs. About 6 hours or so. I'm installing a 16mm master (I think its a Magura, got it from MikesXS.com) and Galfers ss lines. Hope that helps with the feel. Not familiar with tank slap? Hope that's not me slapping the tank with some sensitive anatomical area.  I've thought about eventually installing a steering dampner to help with the unsprung weight. Any thoughts. Sorry to hijack your post btw, Chrisbikes. Hope your original questions is answered. Take care guys. Have a safe and happy new years (remember all the amateur "beverage" enthusiasts are on the road). Gary Hopwheels |
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jimc
New Member
Posts: 22
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Post by jimc on Dec 31, 2005 0:11:38 GMT -5
Happy New Year Hopwheels (and everybody else)!
I saw your brake disks and I'm impressed. How long did that take? I just bought a set of XS 100 calipers (they look identical to the SR caliper) with a master cylinder. I also bought a set of XS 750 rotors. I was hoping they are the same diameter and thickness as the SRs but I couldn't find out before the auction ended(at least the price was cheap!). I intend to drill them as well and I wanted to know where you found the patterns. I've been scratching my head on how I was going to lay out the holes. Also, did you lose a noticeable amount of weight from the drilling? I've seen some rotors that look like swiss cheese and, while it might save some weight, I wonder if the braking (or rotor strength) is compromised. Have you come across any gems of wisdom as regards the number of holes? I'd like to put in as many as possible to reduce unsprung weight.
Thanks,
Jim
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Post by hopwheels on Dec 31, 2005 11:06:19 GMT -5
Hey Jim: Thanks. I downloaded the patterns here liberalredneck.org/techfiles/XS650rotors/and then modified them slightly. The pattern is in 3rds so it will print out of an 8.5x11 printer and has a left and right side. Simply cut the pieces out and tape them together for the full circle. I punched the individual holes out of the pattern with a paper punch, then used spray adhesive to temporarily adhere the template to the disc, then used spray paint to transfer the hole pattern onto the disc. If you go to www.xs650garage.com/ on page 3 of their "chasis chat" section, part way down, you'll find that boards discussion on drilled rotors. Found some great info there as well. Best tip I can relate is to be patient, and to use as low a drill speed as you can. I burned up several titanium bits before ratcheting my drill down to 700rpm. Then it was like butter. I was concerned as well about too many holes affecting stopping power. So I went with this design. It did reduce the weight more than I thought. Good luck and remember the tunes and beverages. Gary Hopwheels |
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jimc
New Member
Posts: 22
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Post by jimc on Dec 31, 2005 13:40:02 GMT -5
Thanks Gary!
I found the XS garage website and saw the discussion. That is very helpful. I also reread your last post and saw the 6 hours you spent (yikes!). I will definitely have to make sure the mini fridge is well stocked in the garage. I'd love to see how your bike is coming along. Can you post a picture? I still haven't figured out how to do that on this forum.
Thanks again and Happy New Year,
Jim
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Post by chrisbikes on Jan 19, 2006 20:42:12 GMT -5
Thanks everybody - lots of good tips and I downloaded that hole pattern. Think I've found someone to do, as this is beyond my cheapie drill press!
BTW, anybody got a brand of pad they'd recommend? Sintered or non?
(And no Gary, you didn't hijack!)
Chris
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Post by chrisbikes on Feb 17, 2006 21:38:15 GMT -5
Update on my front disc..............
found an automotive machine shop practically under my nose here in Cambridge and they knew exactly what I wanted!
Using the pattern you refered me to Gary as machinist was fine with it - we'll see how it turns out........
Someone asked if it vagueness was because I'd done a double disc set-up?
Nope, all stock.
Chris
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Post by hopwheels on Feb 18, 2006 11:09:27 GMT -5
Cool! Can't wait to see how it turns out.
Gary
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