Clutch Plates on 250's

[Blurredman]

Has anyone else noticed how clutch friction plates from places such as 'MZ-b' are 3.5mm accross, when various books state a friction plate shouldn't really be any more than 3.1mm?

When I first got my bike ('87 ETZ250) I had put GL5 transmission oil in it, unawares of the problems that that would cause, and I doubt I need to explain to those who already know why one must not use GL5 in the machine.


Eventually I decided that, because I needed to take the piston out to inspect it and the barrel (plus one day the air box collected all this water and went through the carb to the engine!! , I may as well rebuild the clutch (at £1 for a brand new friction plate why not! Plus it would last me a lifetime).

I did that. And put it all back together, although the last plain plate's teeth did sit into the grooves in the Clutch housing, they weren't all inspiring that they were all that secure. They were however, but only just, this showed how thick the plates were.

The clutch fully secured, the typical gap (although they do vary to a small degree) was about 3.5mm in the 'tell-tale' gap between the back plate and the surround. As long as it didn't hit the main gear behind the clutch I presumed it would be fine.


When I got the bike back together, the clutch was extrememly stiff, it was a clutch, but it was like pulling a brick up with two fingers, and then you'd suddenly hit this barrier.


However, it did work! It dragged like hell, I had to have the bike set to idle at 1,500k rpm in neutral so that it would idle at 1,200k rpm when in gear as for it not to bog down.

The clutch was so stiff it would bog slightly when pulling away, and also break cables!


Yesterday I decided enough was enough, and it obviously wasn't going to wear down to an acceptable standard possibly ever the amount I use it.

I am glad I invested and adapted tools to get access to the clutch, it's easy when you know how!!!

Anyway, I took the old friction plates, and staggered the new and old against eachother. New, plain, old, plain, new, plain, old, plain, new.

Put it back together, OMG, I have a proper clutch back. It's alot lighter, I now believe that the 'block' I would get was the max amount of distance I could gain between the plates before the pressure plate contacted the main unit on the clutch. Forever they were in contact.

Now the bike is set to idle at 1,200k rpm and although the clutch drags the tiniest bit, it is so very neglegeble and there is practically no difference between neutral and in gear. I am very pleased.



But the issue is thus, why are the brand new clutch friction plates thicker than the machine can cope with?

[DAVID THOMPSON]

QUALITY CONTROL

has disappeared from a lot of companies
and it shows

[MichaelTorre]

In america how do I avoid gl5?

Or what's a good substitute?

When I walk into Napa they are just going to give me " the look" when I ask for transmission oil
M

[Blurredman]

I wouldn't know since I live in Britain.

However, when looking at the selection of oils, inspect the bottle's specifications. If it states GL5 stay away, if it states GL3/GL4 then that'll be the one to take.



I believe, but i'm not sure, that any type of oil (Semi-Synthetic or Mineral) at 75 up to 90 weight would be sufficient as long as it is GL3/GL4.

[MichaelTorre]

Thank you
I have found the GL ratings since you woke me up to it.
Helps a lot, since we ate self taught DIY 'ers.
M

[Blurredman]

I wouldn't have had to buy new clutch plates if it wasn't for this information being in the Haynes manual (neglects to mention GL grades in the transmission oil).


I also did this to another clutch on my CX500. I had to buy new plates after finding out semi synthetic oil was too slippery and it needs mineral only, which it also neglected to mention.