Warped Brake Rotors

[mcgovern61]

My front right side '82 vented rotor is slightly warped. Not much, just enough that when I pull the front brakes at high speed my front teeth chatter!!!!! :rant:

They are within the 4MM+ range and I would like to try to get them cut, but there doesn't seem to be anywhere around here that cuts motorcycle rotors. Just for the record, has anyone ever had their rotors cut? 2nd, am I wasting time and should just get ebay specials (unless someone has some good '82 rotors for sale)

 

[scdmarx]

I cut my 82's on the brake lathe at work. The finish wasn't pretty, but at least the were straight. The hardest part of the job was to get the rotors trued up on the lathe. A guy would really need to fabricate some type of adapter to mount them with, to get them trued and centered. I just used what we had and bumped them with a mallet while eyeballing them. Also, they are stainless, so the metal cuts different than the cast that I'm used to. Would've been nice to be able to adjust the feed, but there is no adjustment on our antique lathe. A CNC grinder would be cool. Buttom line is, if you can get somebody to do it, it can be done.

If you wanna pay shipping I'd be willing to have a go at it. But you might find something useable on ebay cheaper than, or just as cheap as, shipping to me both ways.

 

[mcgovern61]

Thats good news Ron that you could cut them. I am going to keep looking for a shop machine shop around here. At one point NAPA would do it. But around here they aren't anymore. If I can't find a shop....there's always Ebay.

 

[slabghost]

Check with some of the tire and alignment shops. Some still turn rotors.

 

[AApple]

I fully intend to at least attempt to turn mine myself on my brake lathe(also an antique) when the time comes. I wasn't aware that they were stainless, tho, so that do present a little challenge. Might have to gets some new bits/cutters. :builder:

 

[Omega Man]

There is a guy on FleaBay that works on motorcycle rotors. You might check that option, as he states that due the stainless steel material they aren't appropriate for lathing. You can find the guy in the pages that have brake parts.

~O~

 

[scdmarx]

I fully intend to at least attempt to turn mine myself on my brake lathe(also an antique) when the time comes. I wasn't aware that they were stainless, tho, so that do present a little challenge. Might have to gets some new bits/cutters. :builder:

Chatter was a big problem. They are so thin, and not all one piece. Very hard to dampen the chatter. Thats why the finish didn't look so good. But they were straight and prformed very well when I was done.

 

[mcgovern61]

Well, after not finding a local shop, I am resorting to used rotors. Before I throw my business to Ebay, does anyone have a good '82 vented rotor for sale?

 

[Andyb]

Well, after not finding a local shop, I am resorting to used rotors. Before I throw my business to Ebay, does anyone have a good '82 vented rotor for sale?

These guys https://www.truedisk.net/ are getting high marks over on NGW.

 

[mcgovern61]

Thanks Andy! I sent them an email to see if they think there is enough meat to fix them.

 

[OldWrench]

I’m dealing with this issue right now. The rotors on my 83 are too thin and the price for new is outrageous. I have a complete machine shop and have decided to make new rotors. I have ordered the steel and plan on cutting new rotors and riveting them on to the hub. This will be my first attempt at making rotors, I also have our head machinist working with me on this project. After testing if all goes well I’ll make up a few sets of front and rear for others who may need new rotors.

 

[dan filipi]

That would be awesome if you can make them!
I'll be looking for a rear soon.

 

[scdmarx]

I have a complete machine shop and have decided to make new rotors.

Wow! :lust: I'm envious!
Y'know, a guy needs a machine shop.

 

[Omega Man]

I have a complete machine shop and have decided to make new rotors.

Wow! :lust: I'm envious!
Y'know, a guy needs a machine shop.

I thought you had one from the pic in your signature.

~O~

 

[Omega Man]

I’m dealing with this issue right now. The rotors on my 83 are too thin and the price for new is outrageous. I have a complete machine shop and have decided to make new rotors. I have ordered the steel and plan on cutting new rotors and riveting them on to the hub. This will be my first attempt at making rotors, I also have our head machinist working with me on this project. After testing if all goes well I’ll make up a few sets of front and rear for others who may need new rotors.

Let me know how much if it works out, I even have a spare set I could send you for the riveting.

~O~

 

[scdmarx]

I thought you had one from the pic in your signature.

~O~

That was a picture my daughter took for some project for her photogrphy class. She stopped by my work one day to snap a couple shots. We have 2 brake lathes, bench grinders, a belt sander, medium drill press, valve grinder & seat cutters, mini broach, chop saw, welders, exhaust pipe bender, etc. Mostly "run of the mill" car shop stuff. In the back room I have seen a bore master and a band saw packed away in the dark corners. The old man says he ordered a plasma cutter from Harbor Freight, but I have no idea how good it's gonna work. I wish we had a mill and lathe and stuff, but it's not like a real machine shop. I've always wanted to learn how to grind cranks. The industry has gone though many changes through out my career. Repair shops just don't do much engine work anymore. Most days I feel more like a TV repairman than anything else. Scanner, lab scope with low amp clamp, power probe, gas analyzer, PC based info systems, etc. The on going learning curve is what keeps my interest, but sometimes I kinda miss the measuring/machining/assembly and fabricating stuff from the good ol'days.
Then there's the mechanics hand tools. Just mine alone....I stopped counting somewhere around 60k. It's getting harder all the time to keep up. As long as there are engineers, there will be a new tool needed to complete the repair.
I think it would be so cool to make brake rotors - or all kinds of different parts at affordable prices for all you guys!

 

[OldWrench]

Let me know how much if it works out, I even have a spare set I could send you for the riveting.

The rivets on these rotors are hot rivets and that presents a little problem for us. Most companies are moving away from hot rivet because of what is required to install them. We were thinking we could use grade 8 fasteners by threading the rotor and locking with a nut. They also make the hollow steel rivet that may be a better option. It is obvious the fit must be perfect. Making the rotor is the easy part, attaching it to the hub properly is another issue right now but a critical one.
The other option is to make a one piece hub and rotor and they just may be a better option but more costly and time consuming. We can make the rotor in about thirty minutes, making hub and rotor would require a lot more time.
Another option would be to weld the new rotor to the hub but that would mean no future replacement of just the rotor.
This is an idea and work in progress at this point and wouldn’t want to sell any until proven to work perfectly.

If anyone has any thoughts on this I would really like hearing from you.

 

[scdmarx]

I'm thinking fine thread fastener with thread locker. I'm wondering if "alternative rivets" might work loose after several heat cycles?

 

[dan filipi]

Hardened bolts and loktite seems like a no brainer, or am I missing something obvious again?

 

[OldWrench]

I'm thinking fine thread fastener with thread locker. I'm wondering if "alternative rivets" might work loose after several heat cycles?

That is a good point on the alternate rivets and I'm just not sure. I was considering a grade 8 bolt with a collar welded to the hub and and then bolt the rotor to the hub. I would want the collar on the bolt to be sized so the rotor almost required a press fit eliminating any free play in the rotor bolt fit. The concern I have with self locking nets is the heat from the rotors effecting the plastic on the nut, same issue with locktite. I was wondering about flairing the end of the bolt once the nut is secured.