OzVMX Forum

Clubroom => Tech Talk => Topic started by: Slow Pete on October 20, 2021, 06:44:58 pm

Title: 86 RM250 Clutch problems
Post by: Slow Pete on October 20, 2021, 06:44:58 pm

Hi All,
          I have a problem with the clutch on my 86 RM250.  I didn't rebuild the bike, but I have replaced the springs and metal plates with OEM parts.   The fiber plates look new and  measure 2.8ish mm thick which according to my Clymer manual is within spec.  [As are the metal at 2.00mm]The clutch cage is not grooved and in good order, it looks like the correct setup when I check the parts list. 

The clutch will not disengage, the plates are not sticking together and spin freely when not tightened down.   When you pull the lever in you can feel the cable trying to stretch, I have tried 2 new cables, same result.  No amount of adjusting helps, it feels more like a brake than a clutch.   The pinion release is straight and looks to operate fine. 

When I take out ether a metal or fiber plate,  it feels good and disengages, but unfortunately it then slips.  The only thing I can think is that the fiber plates are too thick despite what the Clymer manual says.   I have several older RM clutches and the fiber plates in them are all thicker so no use trying them.   

I have rebuilt several RMs from 80 - 87 and am completely stumped.   Maybe I can lock tight the spring bolts and back them off but am concerned they may com loose.     

Any suggestions will be greatly appreciated.

Title: Re: 86 RM250 Clutch problems
Post by: Tomas on October 20, 2021, 10:29:45 pm

aren't you missing a washer between clutch basket and clutch hub?

Title: Re: 86 RM250 Clutch problems
Post by: Slow Pete on October 21, 2021, 12:44:44 am

Hi Tomas,
                Washer is there,  I measured the thickness and it is correct.


Pete

Title: Re: 86 RM250 Clutch problems
Post by: Tomas on October 21, 2021, 01:04:55 am

Hi Pete
What about those new springs? Is the wire the same thickness as the old ones. Some times you may have OEM part that is suitable to such and such bike but they are slightly different. I mean they are marked as superseded parts or something. for example the spring may have  the same length and outside diameter but the spring wire is thicker and when the clutch bolts are fully in, springs are fully compressed so the re is no movement when you pull on clutch lever. Thats all I can think of
Tomas

Title: Re: 86 RM250 Clutch problems
Post by: bazza on October 21, 2021, 10:03:52 am

if plates are correct thickness sounds like springs binding

Title: Re: 86 RM250 Clutch problems
Post by: Slow Pete on October 21, 2021, 12:31:01 pm

Thanks Bazza and Tomas.     Sounds logical, I will have a look at that. 


Pete