Machining discs?

[hredder]

Hi I have a ZXR750 89 which is in need of new discs but am having difficulty finding any at a resonable price (am reluctant to pay half the value of the bike on two discs).
This leads me to my question. This might sound a bit dodgy but can't think of a reason why it would not work. The 91-03 model ZXR's use a different disc size which is only different in the OD ie 320mm vs 310 on my 89. The bolt pattern etc is the same only the OD is different. There are a lot more of the latter model discs around and was thinking of getting a pair and getting them machined down to 310mm.
Assuming I get this done by someone with a few clues can anyone suggest why this would not work or be a bad idea?
Cheers

[hayd3n]

sounds like a great idea

[FJRider]

As long as outside diameter is the only difference, there shouldn't be any issues.

[racerhead]

Just be careful that the surface area of the disc is big enough for the pad. With the outside diameter been a different size I would imagine the inside may also be a different size. But if all is ok then go for it:niceone:

[jonbuoy]

Would that 10mm cut still leave enough meat around the vent holes?

[hredder]

Just be careful that the surface area of the disc is big enough for the pad. With the outside diameter been a different size I would imagine the inside may also be a different size. But if all is ok then go for it:niceone:

Thats the only measurment I have not checked. Just wanted to know if there was any thoughts on why it was a really bad idea before getting out the verniers.

Cheers :)
(and thanks everyone else)

[hayd3n]

bumptious bump

[imdying]

http://metalgear.com.au/mcmodelpart.asp?modelid=1394&makeid=44

Buy new ones. Any bike shop in NZ can supply them. You'll be looking at under $600 for the pair, including pads.

If your bike is worth such little money that that price is unacceptable, it's time to get a new bike. There are plenty of places to scrimp on money, tyres brakes and oil aren't one of those places though.

Starve for a month, you're worth it.

[sharky]

I've tried to get this done. Nobody would touch them. If you find someone willing to do it let me know.

[Lee Rusty]

I once turned an oversize honda disc to replace a BMW one> On that I also had to redrill the bolt pattern.

However bear in mind stainless discs are very hard and difficult to turn If you are paying it wont be much cheaper than getting originals resurfaced or replaced.

If you can do it yourself you should be fine but be careful you cant fix a cock up

once done mine work a treat and are still on the m/c working well to this day

[sharky]

Actually come to think of mine were 310mm and i needed them to be 300mm. So mine may fit yours??? Save you the trouble (off ZXR400-L) If you're keen PM all the dimensions and I'll check them.

[imdying]

Actually come to think of mine were 310mm and i needed them to be 300mm. So mine may fit yours??? Save you the trouble (off ZXR400-L) If you're keen PM all the dimensions and I'll check them.Yes, the ZXR750 H and the ZXR400L use the same discs.

http://metalgear.com.au/mcmodelpart.asp?modelid=1163&makeid=
http://metalgear.com.au/mcmodelpart.asp?modelid=1394&makeid=44

[Max Preload]

Would that 10mm cut still leave enough meat around the vent holes?

5mm cut....

[hredder]

http://metalgear.com.au/mcmodelpart.asp?modelid=1394&makeid=44

Buy new ones. Any bike shop in NZ can supply them. You'll be looking at under $600 for the pair, including pads.

If your bike is worth such little money that that price is unacceptable, it's time to get a new bike. There are plenty of places to scrimp on money, tyres brakes and oil aren't one of those places though.

Starve for a month, you're worth it.

Yeah agree with the above, am thinking it probably won't save enough $$ to take the risk. Thanks for the link I was having difficulty finding out if any other models used the same discs. This gives me a few more options.