Topic: F model disk wear

[dustyc]

I just picked up a 78 750F and notice the disks have some grooving going on.  I also notice they're thinner than the other models I've seen.

Are they thinner on purpose or have these been turned? 

Is turning them acceptable and if so, how much?

Thanks.

[joeb]

For the 78 f-model service limits are 4.0 mm.  Warpage is .30mm Hope this helps.

[dustyc]

Thanks Joe.  It does help.  Can you point me to where you got those numbers?

[MrZxp]

Can you point me to where you got those numbers?

The minimum thickness is stamped on the disc rotor itself (see accompanying pic). At least it is on my '78 750F......



MIN TH
4MM

Cheers, Phil

[dustyc]

Thanks Phil. 

[MrZxp]

You're most welcome.

Now, if you are in need of replacing your rear disc, I can tell you from personal experience, that a disc off a DOHC CB750/900 will do nicely as a replacement. That is what the wrecker sent me anyways and I couldn't see any differences in it compared to my old one. (Of course the wrecker could have mis-labeled his stock for all I know!)

My old disc was .2mm under spec according to the inspector. 

All these things (specifications etc) are in the F2 workshop manual - do you not have a copy? It was available for download off this site somewhere I believe... yes, here it is, the CB750 K8 F3 workshop manual:
http://forums.sohc4.net/index.php?topic=17788.0

Cheers, Phil

[dustyc]

More good info.  I downloaded the manual already and will be reading up on the bike.  Hadn't gotten around to any cross referencing of parts.  Thanks for a point in the right direction.  I haven't had a chance to measure them yet, but I'll be checking them this weekend.

[joeb]

Sorry for the late reply but I got the info from my shop manuel from Honda.