Hello fellow gassers!
Been having an awkward problem and i think it's time to direct it to this forum, the one-stop place for all gasgas related info! If you can't fix this... nobody can!
Rebuilt my bike completely replacing anything that needed replacement, and one of the things done was to rebuild the rear caliper as the piston had melted the seal around it and would not go fully out, leaving me without a rear brake on a dangerous race. (crashed big time too)
Anyway, As i was putting things together a problem came up that was unpredictable and really hard to fix.
I ordered the seals for the caliper and i received two seals with two different part numbers (not a rebuild kit) and they are both thin (both seem like fitting in the outer groove only) and they are
different diameter???
After this delaer stopped responding to my emails i tried another and asked him for the thick seal and i received it, but this too is the second size, the one that won't fit due to diameter (seal is bigger than the piston)
My bike is a 2013 (EC250) and even though i read about a difference between the calipers of pre-2009 to post 2009, there is nothing online explaining what the difference is.
Coincidentially a friend brought a bike over to do some similar rebuild work and we have the exact same piston.
I own a second bike (YZ125) and the second size of seal i receive is the one that fits both the rear piston of the YZ (slightly wider piston) and the front pistons of both bikes.
The only piston i see with a smaller diameter is the rear GasGas piston and i thought it was funny that a 250 had a smaller piston than a 125, but then it sopped being funny when i tried finding seals for it!
Any idea what's going on here? does my bike have the 2009 caliper? (There's some story behind this bike... let's consider it a second hand bike so we save some talk, but it's a bike built from an official dealer that i found different model parts on it. (all the bad stuff) but at least the frame and engine have been verified to be 2013ers)
So the chance of foul play exists and big time. Not rushing that conclusion, just letting you know that i didn't receive this "in the box".
Somebody know if there's a difference in piston sizes between the -2009 to +2009?
I might end up using a thick seal for the front, but that's not my favorite way of making a break reliable to race! ( i don't race no mo', but i do ride it like i stole it!)
edit: no i can't, they are different diameter dummy!
Your knowledge is valuable and highly appreciated so i can get back to doing that!
P.S. and my gift of appreciation for your help :
The piston in the image is titanium (but that doesn't affect the size :P)
Titanium does not transfer heat as fast as steel and it is 50% lighter for your unsprung weight concerns. It's a super upgrade (only for the rear) and priced real close to the original part.
find them at
www.titanclassics.com (you will find it by size, not model/bike as GGs are not listed!)
It's a KTM world ;-)
Thanks again!