Could someone look something up in a CB500 manual?

[stinkwheel]

I'm looking for the allowable warpage on a front brake disc in my quest to track down the reason for it pulsing at the brake lever. It's a CB500SY.

I've got about 0.15mm at the outside edge and 0.07mm at the inside edge of the braking surface.

Also, oddly, the disc itself appears to be slightly oval. If I put the dial guage against the edge of the central rim of the disc, I get 0.4mm runoff. Can't think that this would affect the braking performance though and it could just be that they didn't machine this part to the same sort of tolerance since it isn't directly involved in the braking process.

I'm uploading a couple of videos showing this.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[The Shaggy D.A.]

Nothing mentioned in the workshop manual, but Haynes says :

Disc Thickness (all models)
Standard : 4.80 to 5.20mm
Service limit (min) : 4.00mm

Disc Maximum Runout : 0.10mm
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Chances are quite high you are not in my Monkeysphere, and I don't care about you. Don't take it personally.
Currently : Royal Enfield 350 Meteor
Previously : CB100N > CB250RS > XJ900F > GT550 > GPZ750R/1000RX > AJS M16 > R100RT > Bullet 500 > CB500 > LS650P > Bullet Electra X & YBR125 > Bullet 350 "Superstar" & YBR125 Custom > Royal Enfield Classic 500 Despatch Limited Edition (28 of 200) & CB Two-Fifty Nighthawk > ER5

[stinkwheel]

Maybe at the high side then.

Mind you, it's usually on the middle of the disc working surface that you measure it in which case it's pretty much bang-on the limit taking an average of the inner and outer edge readings (there's nowhere in the middle without holes to put the dial guage on).

Video

Still, I think the pulsing is really excessive for that amount of runout. It did it with the old disc and it's done it with this disc since it was new out of the box. I think I'll see what difference the new wheel makes.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[stinkwheel]

OVAL?

Mind you, it's still a tiny amount if it is.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Robby]

I think I mentioned this in some other totally unrelated thread, but in short, corrosion between the wheel and the disc. Happened on my old CB500 on the rear disc, with a very thick layer or corrosion between the wheel and disc, forcing the disc out of line. Disc itself was fine once I sanded the corrosion back.

With the disc off the wheel, sand all the corrosion of the wheel where it locates until you have good clean metal. Should work fine then.

[stinkwheel]