Brake rotor service limit?

[BladeRunner9]

Hello all; I'm new here and have a question; I'm starting a rebuild / renew of a 1987 Aspencade that I bought 2 wks ago. Two of the 3 calipers are seized and one rotor is completely shot.
I have inquired at my local dealer what the service limit is on the rotors, oddly they didn't have a listing for 1987! They have every other yr. but not 86~87. Can someone tell me the minimum rotor thickness/service limit?
I know the rear is a different limit than the fronts...thanks for any help....Barry.

[WingAdmin]

I recommend you download the GL1200 Honda service manual from the manuals page here - you'll need it!

The Honda Service Manual lists the front rotor limits on page 13, and the rear brake rotor limits on on page 14:

Front thickness, GL1200D:
Standard 4.5 mm - 5.2 mm (0.18" - 0.20")
Minimum service limit 4.0 mm (0.16")

Front thickness, GL1200A:
Standard 9.9 mm - 10.1 mm (0.39" - 0.40")
Minimum service limit 9.0 mm (0.35")

Rear thickness:
Standard 6.9 mm - 7.1 mm (0.27" - 0.28")
Minimum service limit 6.0 mm (0.24")

It does not make any distinction for any model years, however that manual was printed in 1984.

The 1986-87 parts manual shows:

Front rotor, 86-87 Interstate: 45120-MG9-000
Front rotor, 86-87 Aspencade: 45120-MG9-870
Rear rotor, all 86-87 models: 43120-MG9-000

The 1984-85 parts manual shows:

Front rotor, 84, 84i, 85L: 45120-MG9-000
Front rotor, 84A, 85A: 45120-MG9-870
Rear rotor, all 84-85 models: 43120-MG9-000

So being that the part numbers are identical for all GL1200 years, I'm going to assume that the limits listed for the 84 and 85 models will be the same for the 86 and 87 models.

Hope that helps!

[ekcyclerepair]

The minimum thickness is normally stamped on the rotor itself. Not 100% sure that it's stamped on your bike, but if it is, it will be on the inner diameter and facing away from the wheel. Ernie

[BladeRunner9]

Thanks Wingadmin & ekcyclerepair..just the info I needed!......

[donens]

The minimum thickness is normally stamped on the rotor itself. Not 100% sure that it's stamped on your bike, but if it is, it will be on the inner diameter and facing away from the wheel. Ernie

Confused! How can it be on inner diameter, but facing away from the wheel?

[WingAdmin]

The minimum thickness is normally stamped on the rotor itself. Not 100% sure that it's stamped on your bike, but if it is, it will be on the inner diameter and facing away from the wheel. Ernie

Confused! How can it be on inner diameter, but facing away from the wheel?

He means on the inner part of the rotor. You can see it here:

Minimum thickness

[donens]

Thanks, although that's not facing away from the wheel but facing the wheel.
Picture worth a thousand words.

[joecoolsuncle]

curious as to why the 1200D front rotor thicness is much less than the gl1200A. would that be solely because of weight? material used?

[Rambozo]

Ventilated hollow rotor vs. solid rotor.

[joecoolsuncle]

Ventilated hollow rotor vs. solid rotor.

thanks for that!