Vintage Dirt Bike Q & A

I tore my rear hub apart last night to inspect the brakes and clean everything up Post-race. I found cracks all over backing plate, some at the axle hole, some at the rotating shaft hole, and some more at the pivot boss. I had a friend with a cr480 brake a backing plate in mid race just two weeks ago, same problem i think. Is this a common issue with honda rear drum brakes?? And what, if any upgrades can i try to keep from having this problem. Welding isnt an option due to the magnesium and the shear number of cracks. Also, what models should i look at for spare backing plates?

Thanks!

I'd find a good condition replacement from a 1978, 1979 or 1980 bike. When you rebuild double-check that the backing plate is free to rotate around the insert before you bolt up the torque arm. BTW, the insert is near unobtainable so make sure it is all greased up and there's no dirt getting in. I have several spare backing plates you are happy to try....

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

By "insert" you mean the steel sleave with the slight recess machined in it that the axle passes through?? Mine seemed fine but i should double check, this would seem to be an easy peice to machine if i ever did gaul one. I am considering machining a whole backing plate out of aluminum so i wouldnt ever have to worry about this again, it would be time consuming but fun! One funny thing, the reason i pulled it apart is because i had the adjuster cranked all the way till the spring was binding(on the brake rod). I had also been hearing some squeaks durring my last moto, i figured my pads where gone, but i had plenty of pad left??? Could this be a related issue??