Newbie with clutch problem on EC 125 - 2002

[GasGas]

You should confirm if this bike has any aluminum clutch plates and replace them with steel plates if it does. It may be specific to the MC 125, but the aluminum plates do not last. There were usually a mix of steel and aluminum plates in the MC 125 clutch pack.

[Newtogasgas]

This is a 125 ec

Ya , nothing real close as far as bearing shops go, big places are within a hour but not sure how much help there gonna be for a few bux in o rings..

I?m surprised this isn?t already figured out somewhere..

[450exc115]

I suspect the clutch was designed by Magura and therefore you could use a KTM oring on the piston. Slaven sells one for 5 bucks and might be worth a shot.

https://slavensracing.com/shop/slave...ktm-husqvarna/

I have a 02 MC125 and the bike is a hoot. Basically a copy of the 98-01 YZ125 motor. I'd suggest a smaller carb as the 38mm on mine was overkill for sure and made it tough to get the jetting dialed for a wide range of conditions. I ended up with a 95 KX125 35mm PWK and the bike is sooo much better now. I also found the head squish to be big and having the head cut made it run smooth and clean..

[Zman]

The Orings have a small cross section and may be difficult to find. The mfr of the slave cylinder could be Magura but I would have guessed AJP to match the master cylinders.

I agree on the 35mm PWK from the KX125. I had a post a while back that provided the proper Boyesen coupler from the carb to the reed cage. The 35mm has a smaller output diameter. It ran much better on the bottom and still screamed on top. You can also add some ignition timing to help bottom end too.

[450exc115]

Originally Posted by Zman

The Orings have a small cross section and may be difficult to find. The mfr of the slave cylinder could be Magura but I would have guessed AJP to match the master cylinders.

I agree on the 35mm PWK from the KX125. I had a post a while back that provided the proper Boyesen coupler from the carb to the reed cage. The 35mm has a smaller output diameter. It ran much better on the bottom and still screamed on top. You can also add some ignition timing to help bottom end too.

Boyesen coupler RB-10

[Newtogasgas]

Hey thanks a lot for the replies.

So didn?t hear back from gofasters, so not sure.. there the only one that replied saying they could probably find it..

Ya I?m tempted to hit the bearing place a few towns over and see if any luck.

The outer , thinner one I suspect will be easier, but the main one on the piston , as said above wider then a usual o ring and not sure if it?s possible to find one or, if a regular one will work..

[Zman]

... but the main one on the piston , as said above wider then a usual o ring and not sure if it?s possible to find one or, if a regular one will work..[/QUOTE]

Interesting. I never had need to work on the clutch slave cylinder of our 125s. I assumed it was similar to the 200-300 bikes that have small cross section orings on the slave cylinder piston.

Good luck with the search and please let us know what you find.

[450exc115]

It's probably a X profile that seals in both directions. Also known as a quad ring seal. The KTM one is a single oring profile as the piston has a groove in it.

Matto Cycle in PA is a big GasGas dealer too. In a quick search for the part number it looks like it is a 40-50 for the whole unit and still available.

[Newtogasgas]

Who has it available?

The guy I was talking to , his dealers ?said? they had it but after checking are having a problem locating the kit, as sold only that way.

Drove to a few bearing shops and none had the right size or kind..

This is ridiculous

[compmoto]

I found what appeared to be a piece of "welding slag" in my slave over a year ago. Brand new,with about an hour on it since new. After dressing the inside sealing surface of slave housing, I tried to replace the piston with new. It didn't work well. I went ahead and purchased a new slave cylinder assy from Bud Mattos. Problem solved, after another lesson in bleeding the system multiple times...
In short, the seals are only available with the piston assy, which is at least $50.+... unless someone else has sourced the seal elsewhere, that's the best info I have at this point.
The one you have pictured for your 02 model, looks like my '15 model also.
The truth of the matter is, these are quite underrated 125s imho, I like mine a lot !
Best wishes with yours