sam123 Posted July 25, 2013 Report Share Posted July 25, 2013 Hi All, I have a 2009 GG 125 Txt Pro with marzochi alluminium suspension. I have recently noticed the forks are topping out with a clunk pretty badly, I have also lost all damping settings. I am guessing this means its time for an oil change and top up. I have been looking around for ages for detailed information about how to go about changing the oil in these forks however I cannot seem to find anything! I have found the correct levels and oil type and the gasgas exploded diagram, however I have no idea where to start! If anyone has had the same problem or has managed to change the oil in these forks I would love to hear from you! The bike only gets light use so i cannot think any of the internals are damaged, it seems like a cartridge and air issue Cheers, Sam Quote Link to comment Share on other sites More sharing options...
arnoux Posted July 26, 2013 Report Share Posted July 26, 2013 Sam123 The "clunk" on extension means you have air in the right leg damper cartridge. (95% of the time). This is a reasonably common issue with Marz 40's. There is a few ways of doing this, and not all of them are easy to explain on a forum, but l'll give it a try: Remove front wheel loosen top cap after slacken bolts in top triple clamp. (i have special tool for this with the pins set to match the holes, but they are usually not hard to undo as long as the triple clamp is not clamping on it) remove fork completely from triple clamp. Undo top cap and lower upper fork leg in lower leg. remove top cap (need to pull down pre load spacer to access removal) cap and spring can now be removed undo bolt bottom of fork leg remove damper unit Now you need to refill the damper unit COMPLETELY with oil (5W) - make sure there is no air at all in unit before re-assembly. Check out the exploded parts diagram so you can see the internal parts of the damper unit. Prime this cartridge so it is full of oil and no air bubbles are present. Reassemble and fill with 5W fork oil so when the upper leg is pushed all the way down, there is 160mm of clear space (see diagram available on GG USA sight - tried to download my copy but it was too big) at the top. Quote Link to comment Share on other sites More sharing options...
sam123 Posted July 26, 2013 Author Report Share Posted July 26, 2013 Thank you for getting back to me so quickly! Your information has been very useful! I am trying to remove the top cap ( i have tried pulling down the preload spacer) however i do not know how to remove the top cap, any ideas? Cheers, Sam Quote Link to comment Share on other sites More sharing options...
sam123 Posted July 26, 2013 Author Report Share Posted July 26, 2013 I have managed to get the forks completely appart. I have since changed the oil and I think bled the cartriges by pumping the damped rod with the oil over the level of the cartridge. I have now put them all back together, I am still not getting any damping and the fork continues to top out, I assume there is still trapped air in the system.... any ideas how to fully bleed it and be sure you have done it before fully re assembling the fork? Quote Link to comment Share on other sites More sharing options...
arnoux Posted July 27, 2013 Report Share Posted July 27, 2013 Hi Sam It can be done from the top of the cartridge, but in our shop I prefer to disassemble the forks completely to check all the parts, and make sure nothing is broken, bent etc. The one sure way once you have the cartridge out is, on the bottom remove the little spring clip. You can then remove the the slug and small bottom out spring (that's what we call them anyway). This will then allow you to push the damper rod and piston out and clear and allow you to get all the old oil out, and fresh oil in. (have a good inspection while it is apart). Fill it right up with the cartridge upside down, and slowly pull the piston back in just enough to clear the small holes in the side. Oil will get every where so do it gently. Then put back in the spring, slug and circlip and re-assemble. It's a bit of a messy job, but should sort it if you make sure there is no air trapped. Don't compress the damper unit at all, until after it is re-assembled in the forks, and the leg is full of oil. Quote Link to comment Share on other sites More sharing options...
sam123 Posted July 31, 2013 Author Report Share Posted July 31, 2013 After a lot of swearing and a garage covered in oil I have finally managed to get the rebound side of the bike done. Would you reccomend still doing the compression side? Is it the same proceudure as the rebound leg? Many Thanks, Sam Quote Link to comment Share on other sites More sharing options...
sting32 Posted July 31, 2013 Report Share Posted July 31, 2013 Sam, my bet the answer is YES, make sure you have the AIR out, because then you measure the milimeters of oil after you have pumped the air out, just before you are "done". FWIW, there is video or instructions somewhere, I cannot figure out where I saw it... Quote Link to comment Share on other sites More sharing options...
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