Drilling brake rotors

Has anyone drilled there brake rotors or had it done.? I am interested to see if it helps the front brakes on the ol' Seca. I would imagine it will help them stay a bit cooler in heavy traffic when I'm using them alot. But I'm just wondering if it helps the braking force any?

I'm thinking about getting rid of that cable activated master cylinder also (who ever thought up that idea?!!) so I'm going shopping for a handlebar mounted master cylinder unit that will handle the double calipers. Anyone did that mod? It should work with a master cylinder from a bike with dual front brakes (Yamaha, Honda, Suzuki, or Kawasaki)
Now I see I will be losing the electrical controls when I do this because mine are incorporated in with the cable lever control, so I'll have to use the one from the Maxim I have here. I may go with some better brake lines too.
Anyone? >PD<

 

best mod i ever did was getting a braided stainless steel line on the front... it took braking to a new level that i only vaguely remembered from having a 300 pound bullet bike. as for the electric i ordered a hydraulic pressure activated brake light switch of ebay.... works wonderful just plugs right into the master cylinder (mine is on my bars) I'm not too sure about the dual disc setup as i just have a maxim. let us know how it turns out.

 

It can be done but like 07spacker said, you get better results from replacing the rubber lines with braided lines. Just find any bike that has a dual brake setup and use the master cylinder from that and have a set of braided lines made up. If you do drill the brake rotors, they are a little hard and if not done right, will ruin a set of rotors. You need to have the holes lined up so that anyplace where the pad contacts the rotor is not drilled as the rotor is rotated along the pad. Also make sure you chamfer the freshly drilled holes on the rotor especially, if you are using cast iron rotors!!! there was a problem with that in the late 70's or 80's that were cracking due to sharp angles from the drilling op. If I remember correctly the yamaha's use a type of stainless so make sure you go slow with drill speed and use a bit of oil...

 

OK, thanks!
I guess the drilling idea is out then. I will be gathering the parts for the swap and getting the measurements to get steel lines then. PD

 

I drilled the rotors on all my bikes. It doesn't help the braking directly but makes them look a lot cooler. What it does help is how the rotors wear. After they are drilled they tend to wear more evenly, stay smoother and not get grooved as badly. It's fairly easy to do after you figure out the procedure. If anyone wants to know how to do it email me for directions. I also installed a regular master cylinder on the handlebars with stainless brake lines on the 750 Seca and it made a big improvement like 07spacker said.

 

Steve, thats a cool idea for a cheap mod... I've been reading about what people have been doing and after I get my ss lines I'll drill the rotor.

You have some specs on how you drill them. And do you have to have a drill press?

 

I'm also interested in seeing how you guys have drilled your rotors... personally over the past 2 years I've only heard people telling me not to do it... So I might end up outsourcing the job ($$$ :? ).

I've upgraded my MC to one off of an R6. Simple swap (just have to find somewhere to mount the reservior). You can actually use the stock bolt and lines with no modification... But I opted to go with the R6 banjo bolt and run 2 seperate stainless lines straight from the MC to each caliper - ditched the ugly (pointless) collector under the bottom tripple.

I'm pretty sure *fingers crossed* that the brake light switch from the R6 will wire up fine to the stock harness... 2 leads, same as the stock setup. Haven't tried this yet... I've also swapped clutch levers from the XJ to R6 to keep it all the same (fingers are also crossed that the clutch lever safety switch will wire up).

With the stock line:


Stainless lines (still yet to hook up the brake light switch):


Can see the whole setup here (without the clutch lever):


... I mounted the MC to the gauges with a crappy little bracket and the faring mount from the R6... This will obviously be cleaned up later.

Still haven't ridden since the brake mods, but I'm expecting a huge improvement.

 

Well, drilling the rotors isn't hard if you have all the necessary equipment. First off you need a good drill press with a powerful motor, 1/2" or 3/4" chuck and some NEW, sharp drill bits. Don't even think about it if you don't have a heavy duty drill press, the disks are hard to drill and it takes a lot of power. You need to decide on the size of the holes, I ended up using 1/4" drills and a counter sink bit to chamfer the edges of the holes. You then need to decide what kind of pattern you want. You can find patterns on the internet and print out a pattern or design your own, then transfer it onto the disk with a center punch. After looking at a number of different patterns on various bikes at the dealer I settled on a design that has 4 holes 1/2" apart in a straight line from inside to outside and slanted about 45 degrees with the groups spaced so the first hole of one group overlaps the last hold of the next group on solid disks, on slotted ones they don't overlap. This gives them a swirling look but you have to reverse the pattern for the other side. To layout the pattern on the disk I put the bike up on the center stand and marked the distances from the inside to the outside using a ruler then spun the wheel while I held a Sharpie marker against it to get concentric circles. After taking the disks off I made equally spaced marks between the slots. If they are slotted disks, depending on how far apart the slots are, 3 sets of holes between them for the 1100 and 2 sets of holes between them on the 750 Seca looked right. For solid disks mark the holes equally spaced the same number of degrees all around the disk. I had 96 holes so they were in groups 15 degrees apart. To drill them you need to use a center punch to mark all the holes so you can drill them accurately then drill each one with the 1/4" drill in the drill press using a little oil in each hole to make it easier and prevent overheating. I did it by starting the hole in a number of locations in one sector, then putting some oil in each hole and drilling some more, then adding more oil and drilling again until it went through. Stainless steel is tough and hard to drill and also tends to break the edge off the bit when it exits the hole in the bottom so it helps to put something solid underneath like a piece of hard wood. The drill speed is very important and you need to go slow enough that it doesn't overheat the bit but not too slow. When you get the speed set so the drill is producing solid strands of metal out of the hole as it drills that's the correct speed.
Oddly the drills don't tend to get very dull drilling the hard stainless but since the edges break off you have to keep changing them when they stop cutting. At first I was using a couple of bits on each disk but after I got the speed set correctly I could drill a whole disk without wearing out the bit. After you get all the holes drilled use a countersink bit to chamfer the holes slightly on each side then sand the surface to remove any rough edges around the holes. A solid disk has something like 96 holes and takes FOREVER to drill! It also produces what seems like tons of sharp metal filings that fly all over the place so be prepared to take your time and deal with the mess!

 

I guess I'll wait till I get a drill press. I was looking at new rotors but didn't see
the expense for something that was working. If its not broke'n, don't fix it.
And I need a drill press anyway.

 

http://www.spec2.com/ take a look on this site. They have been around a long time and are very reputable. I have always been told that with Steel roters like the ones on the XJs you schould not campher the holes. When the sharp edges of the holes whipe across the pads it shaves them smooth and helps prevent rotor galling.

 

That may be true since the slots stamped in the discs from the factory were not chamfered and have sharp edges but when you drill the holes you end up with a small ridge around each hole that needs to be removed and the easiest way to do that is to chamfer it it. You could sand it smooth but it would take a lot more sanding if the holes aren't chamfered first.

 

There is no purpose in drilling the brake rotors other than looks. By drilling the rotors, you're potentially compromising the integrity of the rotor itself, and are asking for cracks.

More surface area=better braking. Holes reduce the surface area, and hurt your braking ability. If we were talking about high tech high pressure rotors such as porshce's ceramic/carbon setups, the holes would be great to give gas/moisture a place to go, but in our case its strictly cosmetic.

Unless you really, reeeeally know what you're doing, I would not drill a set of rotors. It's not worth the potential safety issues. (i.e. cracking/breakage under hard breaking)

 

Check out this job on ebay, wow!
http://cgi.ebay.com/ebaymotors/YAMAHA-X ... 0214456356

 

I wouldn't attempt to drill rotors even if I did have a powerful enough drill press and enough sharp, new drills to do the job ten times over.

I'd let a Machine Shop do the job on a machine with precision indexing and the right drill bits, lubing and cooling to get the whole job done without a fuss.

You have too many variables to try and do the math and keep the measurements straight that a Robot can do without error.

If you are going to need vented or drilled rotors ... have a skilled Machinist do the job on a machine that will accomplish the feat with Zero Defects.

 

The holes don't have to be precise at all except it might not look good if they are too uneven. You guys are being silly, if the big slots punched in the discs by the factory doesn't hurt them nothing will.

 

I def see the logic in this statement, maybe to the point if you were to drill them away to nothing, carpy style... But all modern discs are drilled. And most have a much smaller surface area than ours.

I'd say if you drill, and are worried about the effects of having slightly less surface area to break on try upgrading to stainless lines. Would more than offset the difference.

I agree that it's not necessarily the best DIY project and you wouldn't want to screw it up / go too heavy on the drilling (put too many holes in your rotor, too close together).

Not sure about if there are any gains on the street - performance wise - I'm just saying there's no real loss either (unless you screw up).

I have to agree with this too... If you're going to drill the rotors yourself, then consider bringing them to a machine shop to at least be re-surfaced, rather than putting a "countersink" on the holes...
Again, think about a modern brake setup. The holes are Always straight through, with no relief around the edges.

 

knock your socks off guy
http://tinyurl.com/6ota5m
http://tinyurl.com/6a9slm

 

The hot set-up is a diagonal machined groove with a ball tip that does not go thru the rotor, it vents the gasses very effectively, but can accumulate debris-(not pretty).
Also, a perfect pattern of holes won't clean the entire brake pad.
The pattern would have to be offset - ruining the beauty of it.
It's a cosmetic thing, you wouldn't understand.

 

old school, man, it's a thing of beauty

 

I found some information about the benefits of drilling rotors in an article by Joe Minton in Motorcyclist. He's actually talking about improvements to a Virago but it should apply to any bike. On page 3 of the article he says to leave the holes with sharp edges and use a pattern that has all the holes overlapping so they wipe the pads clean and it helps prevent scoring and gooving so you have more flat surface in contact for better braking.

http://viragotech.com/improvingthevirago.html

 

AZsteve - where'd you find patterns for drilling the rotors. I've been searching online but can't seem to find any info?

Edit: just found some, nevermind. For others interested
http://www.rctvonline.net/~xs11/rotors/ ... otors.html

 

There are some online you can download and print out a pattern but I don't remember where. I designed my own.

 

Technically, the papttern is designed by computation of the amount of drilled holes and the circumference of the rotor.

Unless you have advanced skills in machining that job of drilling Brake Rotors is best left to the skilled in Machining.

I saw a few placed online that will drill a pair of Rotors in several patterns for as little as $89.00.

That's less than what the recovery cost will be if you make a mistake.

 

I once asked my machinist about offering such a service, and this was his reply, so I dropped the idea of offering it. I'm not saying to NOT consider doing this, but this is what you need to be aware of before you have someone starting trying to surface and drilling holes in your rotors!:

 

I decided not to drill the rotors anyways. I have slotted rotors already, so it probably wouldn't be a good idea to add any more holes in them. It was just a thought and brought up alot of good ideas here, so it wasn't a total loss. PD

 

Nonsense! Anyone with a drill press can do it. They are just HOLES. It's not rocket science!
Chacal, your mechanist must be an idiot or he's just lazy and doesn't want any work.

 

Perhaps. But he/his shop machines from raw billet titanium all the sniper silencers - suppressors for the US and Swedish armies....some of them with such a large barrel that you'd think they're used to "snipe" tanks. Everytime he gets an order for them my projects get put on the back burner.

On the other hand, he always finds the time to make carb bowl drain screws for me on a timely basis.

So yeah, Steve, I'm sure you're right.

P.S. in his spare time he produces brand new cylinder blocks, heads, and cranks for old Bultaco motorcycles. I unfortunatley have no knowledge or need for those so I don't market those.

 

Chacal,
The more time I spend here with our machinists, the more I understand why you cannot just pop a bunch of holes into a piece of metal and expect it to weather the abuse of being a brake rotor.
Heat development and abatement is a fine science and figures heavily into determining what tool to use and how to make a hole.
Our staff include the guy who made the arms on the Mars lander (that is still working by the way) and a fellow from Wilwood Brakes. Neither one will mess with drilling rotors without the proper equipment.
I trust their opinions highly. Ergo, I'll not be throwin' my rotors on my drill press and lettin'er rip.
Let us all hope your efforts to get those EBC rotors in stock is successful!

 

http://www.tciprecision.com/literature/Blanchard.pdf
http://www.tciprecision.com/products-se ... e-disc.php

 

Dear (Members name edited- REM), or should we call you the pot that called the kettle black. Only an (Edit -REM) with no metallurgy training would think that the drilling and subsequent heating or possible overheating could have no ill effects on the structure of a brake rotor. Or that such a process would absolutely have catastrophic effects. That’s the funny thing about science it takes properly processed information to make an intelligent determination.

(Edited by Moderator R. Massey).

Terms Violation. Warning. Not Authorized. Use Private Message Function in the future!

 

I have seen lousy jobs of this and one that was rusty in the holes that looked pretty bad.

I am not convinced that it is necessary on the older bikes, but I could be wrong.

 

WHISTLE
TIME OUT.


Take it to the Private Messages ... fellows.
Lets not even start one up.

We don't do that in the Public Forum.
I'm calling this play charging ... and offensive foul.

I'm going to be fast with the whistle and your shower if this goes downhill.

Private Messages for arguments.

 

Geeze Polock, you think anyone here could afford a machine like that? I know a few pieces of my anatomy I'd gladly trade for that toy!
As for your comments Mr. Tanner, I would politely suggest that, while you are quite correct about doing a little research to gather knowledge, even I make unqualified remarks now and again (witness "Swing Arm Bearings" in the Chat forum). It is annoying to everyone (including myself when I learn of my ignorance) but it is in the spirit of educating one another that we address errors. Could you perhaps supply some educational links or information to help those of us who do not understand the dynamics involved in this matter? I'd love to see anything you might be able to dig up. Thanks.

 

Robert:
i don't know some of these guys here might be gazillionares !
or maybe someones cousins sister-in-laws niece dates somebody that works with one ?
me, i just use a five inch 60 grit sanding disk and spin the wheel with my hand

 

Drilling Rotors is something a specialist does.
I think that I learned that a so long ago that nobody had a PC to go look it up on.
The indexing is somthing a Maching Tool does.
The Drilling is something a Robot does ... now-a-days.

So there the BIG IF ...
If you are a machinist and have the tools and equipment to drill your own Rotors ... they're your Rotors ... do as you please.

Don't encourage anyone without the skills and precision equipment to attempt to drill the rotors by themselves ... no matter what benefit having drilled Rotors may have.

Its not a "Do It Yourself" Project.
No matter how determined you might be to do the drilling by yourself ...
unless you can do it right ... the first time ...

Don't do it!

A Front Brake Rotor failure on a motorocycle is a catastrophic failure that will send you to flying over the handlebars ...
to the ground
to the hospital
to the Intensive Care Unit ... or, maybe to
the Morgue!

Unless you are QUALIFIED ... and,
have the right EQUIPMENT
Don't even think about it.

And that's the Official Recommendation of this Site.

 

Here here Rick. We've had one or two folks here lucky enough to walk away from catastrophic front disk failure, a VERY rare thing.
Not worth the risk.