-83/84 RM brake/frontwheel?

[ola_martin]

Hey.
I have a RM500 -83 or 84 fork and frontwheel minus backingplate, wonder how specific my search for a plate will have to be? Can i use any RM250/500 twin leading plate in my wheel?

Will a -83 brakeplate fit a -84 frontwheel and vice versa?
Will a -83 frontwheel fit a -84 fork and vice verca?

[lukeb1961]

54210-14300 is common to the 250D and 500D
54210-14500 is common to the 125E / 250E / 500E and 250F

[BAHNZY]

With a small spacer, you can also use a Honda CR450 unit.
They run the same diameter hub & without checking its 160mm from memory.

[LWC82PE]

250 F is disc zedder mistake i guess.

there is a difference between 83 and 84 plates with how the cable attaches. On the 84 the outer is anchored on the plate. on the 83 the outer is anchored on the fork leg and a long section of bare inner wire runs down to the brake plate.

83/84 RM TLS brakes are 130mm dia so i cant see how 160mm Honda would plate would work.

[ola_martin]

Always good to hear from the experts! 

So I can just check on the forkleg if there's a bracket for the frontbrake on it to determine year on the fork?

Is the stopperlug on the fork placed on the same place, so if I have a forkleg with bracket I can grind it off and use the one on the backingplate if I get the 84 plate?

[BAHNZY]

250 F is disc zedder mistake i guess.
there is a difference between 83 and 84 plates with how the cable attaches. On the 84 the outer is anchored on the plate. on the 83 the outer is anchored on the fork leg and a long section of bare inner wire runs down to the brake plate.
83/84 RM TLS brakes are 130mm dia so i cant see how 160mm Honda would plate would work.

As I said from memory.
Went back and checked my files it was the Honda CR480 that used a EBC-327 shoe @ 130x30 mm
When I built my 84 RM125 I used a CR480 backing plate with my 84 RM wheel.

In all the data that I researched, I also had this on file.
According to the EBC catalogue
The RM125 X,Z,D & use a EBC 602 @ 130x28 mm
The RM250 & 465 X,Z use a EBC 621 @ 150x22 mm
The RM125E & RM250/500 D,E use a EBC 622 130x22 mm

1985 (F)
RM125, 250, Disc Brake

1984 (E)
RM125, 250, 500 Twin Leading 54400-14840

1983 (D)
RM125 Leading/Trailing - 64400-40810
RM250, 500 Twin Leading - 54400-14840

1982 (Z)
RM125 Leading/Trailing - 64400-40810
RM250, 465 Leading/Trailing - 54400-14860

1981 (X)
RM125, 250, 465  Leading/Trailing - 64400-40810

In relation to the cable attaching to the backing plate, I’d need to go back and check but I thought that was the difference between a twin leading and a leading trailing system. I.e. The twin leading had the 2 piece outer cable that attached to both the backing plate and the fork and the leading/trailing system had the cable mounted to the fork and not the backing plate (on the 43mm forks)

[BAHNZY]

Always good to hear from the experts! 
So I can just check on the forkleg if there's a bracket for the frontbrake on it to determine year on the fork?
Is the stopperlug on the fork placed on the same place, so if I have a forkleg with bracket I can grind it off and use the one on the backingplate if I get the 84 plate?

Dont grind anything. Take some pics and post them up well help you as best we can.
The upper cable mount on the 84 fork was pressed on not cast as well.

[ola_martin]

Thanks, haven't gotten the parts home yet, so I haven't actually seen them, will put up some pics and measurements when I can. Looks like I've got the expertise here to solve this litte problem 

[cloggy]

LWC82PE is correct as to how the cable stop attaches. I see no reason to disagree on the rest of BAHNZY's very detailed info
I have the later TLS on a set of '81 125 fork legs
 I have to say it's not a very good brake. I updated with a bigger diameter inner cable and different outer, got hubs at a knockdown price and had brake shoes turned down to match
I managed to source everything new except for the TLS linkage
 An engineer reckoned there wasn't enough support within the back plate
So a honda set up may well work better.
 I was at Farleigh castle international meet this and last autumn and the Belgians always turn up with a shedload of works RMs. They use different forks and brakes!

[suzuki27]

Did the guy skim down the brake lining inside the hub as well?
They are tricky to set up, but if you get a good mating surface fit between the brake shoes and the hub lining they work a treat.

[cloggy]

Yeh he did all that
 I had two wheels done identically with one brake plate and two sets of shoes and I don't think it works any better now than a standard DR400 sls brake. Mind you it's got another 60lbs to stop, being on my DR.

[suzuki27]

How is the contact patch/area on the brake shoes after a run on the bike ?- using the front brake a lot of course. The area on the shoes contacting the hub will be obvious and it should be even over the surface of the brake shoes. You won't get it all contacting but around 80-90% say is pretty good. If this is all good ,check that the linkage arm is adjusted correctly.You can do some experimenting with the amount of "turn" it is putting on the brake cams(are these stock). If this is all good and the brake shoe material is not granite they should work pretty good.

[cloggy]

 I did all that but I'll check it over the winter to see if I got it right. Thanks , it's worth looking at now I've done a thousand miles on it.

[LWC82PE]

Do all 83/84 Rm's have the fork leg slot in the brake plate in the same location eg 90 deg to the fork instead of on angle like all the single leading shoes plates? Just wondering if theres 2 types like the yamaha.

[monaro308]

Does this help you Leith?
My '84 RM125 leg