Replacing Rotors with XS1100 sloted rotors

EvenmoreXS

1981 XS650
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I have read several threads on this and wanted to confirm before I moved forward...

Im preparing to replace my forks and want to do my brake pads while I had things off. I was going to clean up my rotors and drill them too, but seeing some threads on how to do that vs. replacing them with xs1100 rotors got my gears turning.

IF I switch rotors, I want it to be a direct bolt on, no extra stuff..... I've read the xs1100 allows for this......I've posted a pic of a rotor as an example of what Im looking at. Let me know if this will work.....


I have a 1981 frame with 35mm 1980 forks. Pic of the forks to be used posted as well.

Can I simply remove and replace my forks and replace the rotors with some like this.???
Any potential problems to look out for...?



If it becomes " A thing " I will just resurface mine and move on .....



Thanks for the advice.
 

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Just make sure you get the right size disc. Some of the dual disc models used two smaller discs, actually the same size as what comes on our rears. I think the fronts on ours are 298mm, but check that to be sure.

Also, the disc you want is as in your picture. Notice the "R" stamped on it. This pertains to the angle and direction of the slots. You want them starting from the inside, to angle out and back AWAY from the direction of wheel rotation. This forces any water, dirt, etc. out and off the disc. The same principle applies to laying out a swirl pattern of holes on a disc. You want the swirls to run out and back AWAY from the direction of rotation. I see them done incorrectly around here quite a bit.

OldDisc.jpg
 
I DO have the dual front disc.

I will email them and see if they can give me the outside diameter to see if its the 298mm.



But in general, if the diameter is right for the front, these should be a direct bolt on replacement..... correct?


Edit: http://www.mikesxs.net/product/30-3065.html says they should be 298 mm.
 
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Yes, the 1100 rotor bolts right up. It's thinner that stock 650 rotor, so you save weight two ways, compared to stock 650 rotor.
 

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Was it ever called a Midnight Specail ??

Seller list it as: 1981 Yamaha XS1100LH 1100 Midnight Special Y340' front right

theres one for the left also.

Sorry to beat a dead horse, but it looks and sounds right,... but man do I hate finding out I was wrong.....


still waiting to find out if they are 298, but I think they are right.

Thanks again everyone.
 
Was it ever called a Midnight Specail ??

Seller list it as: 1981 Yamaha XS1100LH 1100 Midnight Special Y340' front right

theres one for the left also.

Sorry to beat a dead horse, but it looks and sounds right,... but man do I hate finding out I was wrong.....


still waiting to find out if they are 298, but I think they are right.

Thanks again everyone.

Yea there were Midnight Specials, think the 850 had one as well.

Brochure of an 81 XS1100 Midnight Special First pic.

Brochure of an 81 XS1100 Venturer Second pic

Brochure of an 82 XJ1100. Third pic

79 4th

80G 5th pic

Looks like some of the earlier model 1100's didn't have slotted disks
 

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I have xs1100 rotors on mine, not sure what year though. They were a bolt on swap and the same thickness as the 650 rotors. Tough part was finding the left caliper.
 

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Luckily I have both calipers....

I think this answers all my questions for this upgrade. Just have to decide which is the most effective and viable option for my build. Resurface and drill my rotors....time.... replace with slotted rotors.....money.....

Thanks everyone for the help. Greatly appreciated.
 
Can't find it now...........Read an article on the affects and advantages of drilled verse's slotted verses non drilled/slotted, (plain), disks and the heat dissipation was best for drilled rotors and the slotted weren't much , if any, better than plain disks, the slotted disks has more pad wear
 
Yea…..After all my research and looking at my disks, I've pretty much decided to sandblast and drill my rotors, then maybe hit them with the orbital to smooth out the holes and put a random surface on em. Gonna compare the cost and benefits of having a shop drill them or buying a drill press and doing it myself and then still having drill press for the future…..cant believe i don't already have one.

I appreciate all the quick feedback. I'll keep you informed.
 
I think 3M recommends bead blasting, not sand blasting. I've had a $49 HF bench top drill press for many years. I've done lots of discs and tons of other little drilling jobs. Leave the holes sharp edged. Just remove any burrs with a drill bit spun by hand .....

 
I think 3M recommends bead blasting, not sand blasting. I've had a $49 HF bench top drill press for many years. I've done lots of discs and tons of other little drilling jobs. Leave the holes sharp edged. Just remove any burrs with a drill bit spun by hand .....



Yep ! on the bead blasting...

and sweet on the harbor freight drill press. That was my first thought but I haven't done any pricing research yet, so its good to know its an affordable venture.

The rotors would have been $75 at the cheapest including shipping.....so 50-60 for a drill press and then Id still have a drill press and could drill holes in other stuff too.....:D
 
just a fair warning on the hf bench top drill press. i bought one at the end of last summer. the 8", 5 speed model. i didn't use it right away but when i did it made egg shaped holes. everything was solid, but the shaft that moves up and down would wobble. got worse the further down you go. nothing would take out the slop.
 
I think 3M recommends bead blasting, not sand blasting. I've had a $49 HF bench top drill press for many years. I've done lots of discs and tons of other little drilling jobs. Leave the holes sharp edged. Just remove any burrs with a drill bit spun by hand .....


This has got to be up there with watching grass grow or paint dry. Better done under the influence of beta blockers to achieve that kind of accuracy, but I suspect you have a hard template?

Very nice, kudos.
 
Since I have a stack to do, I transferred my paper template to sheet metal. A paper template is only good for a couple uses before it goes to shit. Hopefully this sheet metal one will last a long time .....

DiscPattern4.jpg


DiscPattern6.jpg


DiscPattern.jpg
 
Clever. I guess if you have to do a stack, you could... literally stack them? Never tried, maybe they don't fully spoon. Also only works for same-side rotors.
 
The center spoked area is slightly thicker than the disc area so they don't stack tight. Besides, I don't clamp the disc down, just hold it with one hand while operating the drill press with the other. This is quicker than clamping for every hole and allows the disc to move a little to center itself when you apply the initial pressure to your center-punched hole. You can also push the disc and move the hole location a little at the start of drilling if you don't like its location. I do that mainly on the 1st and last holes in a swirl to get them to the edge of the disc's swept area if need be.
 
Thats a bad ass template 5twins.

Ever loan it out????.....

I need a solid one also to clamp on so I can paint the inside and not get paint on the rotor surface.....you know....while your at it...

Or i could use tape.......:D


Holy Holes Batman! How long does it take you to drill that many holes....?
 
I should have made two, huh, lol. I wouldn't consider loaning it out until I was done with it, but who knows when that would be. Paper templates are fine for just a couple discs.

Yes, there are a lot of holes in my pattern - 15 "swirls" w/ 8 holes each for a total of 120 holes. I'd say it took between one and two hours to drill. I didn't do it all in one sitting. I use a small hole size (3/16") so that makes the drilling pretty easy. And the hole size you choose is important. You don't want the holes any bigger than the disc is thick or else you lose surface area (and improved cooling). The stock 650 discs are 7mm thick so I wouldn't go any bigger than 1/4" on the holes (1/4"=about 6.4mm). Some of those 1100 discs you were considering and one from an SR500 are only 5mm thick. That's what I had in mind when choosing my hole size because I happen to have a couple SR500 discs. 3/16" is just under 5mm plus, like I said, it drills easier than a larger hole.
 
Just to throw in my .02 worth. The XS1100 Specials used a leading axle fork and the smaller rotors. The same with the Xs750 and XS850. Get parts from a standard model. The calipers are the same as the XS650.
The brake calipers on the leading edge forks are very different. The mount with a through bolt, back to front into the forks. Can't use them.
I'm not sure on the thickness if any of the XS750, 850 or 1100 used the 5 mm thick rotors. I think they used them on the lighter bikes. The bigger heavier needed the extra mass for heat dissipation. The lighter bike didn't have this problem.
I have a 7mm set of slotted rotors on the 81 and 5 mm slotted rotors on the 75. The 5 mm are much lighter. Better than 25% lighter.
Both bike stop very well. I use the stock 14 mm Master cylinder on the 81. I just bought and added one of those $27 Chinese masters sold on Ebay. It has issues, Not as nicely finished and the mirror mount is right hand thread so the stock right side mirror won't fit.
I do have a metric tap and die set, wonder if I can rethread the mirror or the master.
A stock lever fits and works, just no hole in the body for the return spring.
Leo
 
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