RD250b Clutch Pressure Plate ID

[2taol]

Hi all, small issue with replacement clutch springs for my RD.

I got some from Norbo but they are too big and wont fit into the pressure plate. Norbo says the springs are correct and I dont doubt him at all.

The springs I took out measure 14.5mm diameter at their ends, the new ones measure 16.5.

I am wondering if I have a different plate on the clutch, could anyone help ID it?





Thanks in advance!

[reedpete]

It looks like a B pressure plate but I can go check to see what one looks like tomorrow, also see what diameter spring can fit.

[2taol]

thanks pete i recon 16mm diameter would fit, atually with compression maybe not.

im thinking as the srpings compress the diameter increases

[reedpete]

So...
That pressure plate is from a 73 or early 74 (A) RD, used same pressure plate as the YR5 and uses 14mm springs. However the 360 pressure plate Used on late A and B also uses 14mm springs. It wasn’t until the 1A0 that they changed to 16mm. 1A0 Plate started use on the RD250C but then remain in use through to the LC.
The parts list show the progression but the dimensions of the spring are not obvious to me just from the part number. Maybe there is some type of code same as with nuts n bolts but I’m not au fait with that.
So in summary 16mm springs won’t fit in any round tank RD. In this instance Norbo is half correct, 16mm springs are used and fit on Aircooled clutch plate ....(.just not on B or earlier..)

Suggestion

If your clutch is slipping a bit...just bung in an additional steel plate....

[2taol]

Brilliant thanks Pete, thanks for the detailed info.

[2taol]

could I use a C,D pressure plate on my A,B clutch?

[reedpete]

Not really...
Or , if you did there are consequences etc.
The bolts for the B clutch are shouldered, so you’d still have to use those but their head is a bit small for the 16mm spring and also the shoulder has more clearance so the spring will probably wander a bit under compression.
At a push it will work but defo not intended to be.

What’s the prob you are trying to solve? I’m sure the 14mm spring must be available and probably common part on other bikes.

[2taol]

Thank pete, im in the process of building an engine and im building the clutch ATM so i guess the problem is the spring type, i'll have to chat to Norbo and see what can be done.

thanks for all the help.

[reedpete]

Original part is 90501-20123

Superceeded by 9050120361

£20 ish a set from Fowler’s