81R Mod needed

[firefirefire90]

for the 81 250R, there is a front disk brake and a rear drum. What i have been told, you are able to put the 82 rear on the 81 and upgrade the front to whatever you want to do. But for those of us who can only do engine mods, is there a possible way to drill the front brake on the 81R? Because 1982 250Rs has drilled front disks and the 81R did not. I do not want to lose the oldschool frontend and just want to know if you can drill it. Thank you.

[thedeatons]

Having a rotor "cross-drilled" is a precision process. First of all there are certain patterns of holes that work and certain patterns that weaken the rotor and lead to premature failure, which is bad when you're talking about brakes. That being said, if you do end up having a machine shop do it, it's a good idea to have them chamfer the holes, which is basically like countersinking them. Your best bet is to find an aftermarket company that produces them pre-cross-drilled. It's a good idea to buy from a reputable company like Braking, EBC, Galfer or Wave, if in fact they produce them for your machine. Any supergenius with a drill press can drill some holes in a neato looking pattern on a rotor, then sell it as "cross-drilled", but those are the dangerous ones, where no research has been done on the heating and embrittlement properties of the metal after drilling. Each hole drilled will produce heat and realign the particles within the steel. It is obviously important to stress relieve the rotors after this is done, by baking in an oven. Anyway, we're getting way to detailed here, sorry for rambling.... Good luck in your search, and beware of the shadetree rotor... James

[200xman]

The rear brakes are not interchangeable unless you do some fabrication. The 81 frame has no mounts for the master cylinder or rezzy. My 81 stops fine with the drum so just get sme new shoes and be done with it.

[350x'inNY]

Get an 82R front rotor..... it's already drilled versus the 81R solid disk.