KymcoForum.com
Scooters - Big Bore => Xciting 500 => Topic started by: XavierTico on January 03, 2010, 04:18:45 PM
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There is fluid leaking from the top of the left front fork shock tube on my 2006 500X. Does this mean the whole assembly has to be replaced? Can you replace just one side? The parts manual shows it as a unit, and it looks like an expensive unit at that.
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If it is leaking from the very top of the tube, it is just an o-ring around the top cap, easy fix, you can probably get the correct size o-ring from a local auto parts store. If it is leaking where the stanchion tube meets the lower legs, that is the oil seal. You can replace just the oil seal, but it requires taking the leg apart. It's really not that difficult with a little mechanical know-how, and the specified oil volume.
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Thanks for your help. It appears it's leaking where the upper piston goes into the lower painted sleeve, and that it's been this way for at least a little while as the paint is blistered around the top.
I found a parts diagram here:
http://www.stadiumyamaha.com/pages/parts/viewbybrand/73/0/1245/50/default.aspx (http://www.stadiumyamaha.com/pages/parts/viewbybrand/73/0/1245/50/default.aspx)
I'm going to try to find out if I can buy a recommended list of parts that would constitute a rebuild kit for replacing the seal. My mechanical skills were once pretty good, but that was many years ago. After I remove the fork tube, will the piston be loaded under any very considerable spring pressure? Will I need any special tools to reassemble it or keep it from hitting the ceiling when I take out the containing nut? And where would I find the specified oil volume and type? Does it have to be bled somehow?
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Sorry, that link doesn't go to the page with the blow up of the fork assembly. Let's try this one:
http://webservices.motorsportdealers.com/parts/partImages/KYM/4/03/11/0125.Gif (http://webservices.motorsportdealers.com/parts/partImages/KYM/4/03/11/0125.Gif)
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I just did the forks on my Vento and it was very easy, I rebuild mountain bike suspension for a living though! These scooter forks are much simpler! You don't need any special tools. The only somewhat uncommon one is usually an allen wrench attached to a socket for removing the bolt inside the fork at the very bottom which holds the lower leg and stanchion tube together. On my Vento I used an 8mm allen socket attached to two long extensions.
You can loosen the two pinch bolts in the crown and the whole lower assembly can be removed. Then you will remove the top cap. The spring underneath is under a little tension, but not enough to shoot anything out, just be ready for it. Then remove the spring and drain the oil. Next is where the long allen wrench comes in. It is located all the way at the bottom inside the tube. I had to gently clamp the lower section in a vice to loosen this bolt. Once you get it undone, the stanchion tube should slide out of the lower legs. Then you gently pry out the old oil seal. I have found that a open ended wrench works well for this, just be careful not to gouge into the leg itself. To install the new seal, apply some fork oil, or even better, fork grease, I like slick honey (used for mt. bikes). The seal sometimes be pressed in with a large socket that fits just around the outer flange, also an aerosol can the right size can be used. Then just reassemble everything in reverse. Put some blue loctite on the inside allen bolt. Fill with the specified weight and volume of oil (you may try calling Kymco for this), and your ready to ride!
Feel free to ask any questions for further clarification, I hope this makes sense!
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It makes a good deal of sense, though I'm not crystal clear on how the whole thing fits together. It looks like everything piles in from the top except that one allen bolt and washer. It's not real clear where and when the oil would go in, but I'm hoping I can get some information from the local dealer. I've got the service manual. Getting the unit off the bike looks straight forward. Digging out the old seals and reinstalling the new sounds like the most challenging part and they don't cover it in the service manual.
I appreciate the instructions. I'm going to see if I can order the parts I need for this project and somehow duck the 100% import duty (I live in Costa Rica).
I'm also not particularly well equipped with tools. I'll have to scrounge about some for large sockets and extensions. But I have so little faith in the local dealer that I really don't have a lot of options.
Thanks again for your input. I'll keep you posted on how this goes.
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You are correct everything goes in from the top. The allen bolt just goes under the spring, still from the top. You fill the oil from the top, the last thing you do before you put the top cap back on, or you can put the oil in before the spring, doesn't matter. The seal isn't really that hard to install, sometimes you can do it just by hand. Good luck! :)
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Nothing beats doing it right the first time, and shaka has you well on the way! I have used 3/4oz of Brake Fluid to swell the seal, and it works like a charm. Add it straight to the fork, and ride. A few hours of riding will swell the seal, and no more leak. Doesn't beat replacing it, but for the lazy types (me) it works.
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OK, thanks to the excellent advice I received from Shaka I skipped buying the whole fork unit for $119 and bought a seal for $5. The installation was pretty straight forward. Getting the tube out is easy once the front wheel is off, (which is also easy.) It took me a while to realize there was a retaining clip holding the seal and its attendant washers in the tube. Once I got that clip out, however, it still felt like there was something holding everything in the tube. Fortunately I had an experienced mechanic there to ask about it, he told me there was nothing else, just pull it out. He was right. To put it back together took some careful seating of the washers with a light hammer and a makeshift punch made from an old screwdriver blade. Our two different sources for how much oil to put in said 2 - 6 ounces and 6-8, so we decided on 6. It all went back together smoothly and it works great now. No leaks. Total time invested about 4 hours which included a lot of head scratching, a few phone calls to the dealer, and a short hunt for fork oil. Thanks for all the help.
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That is all god stuff! Glad to see it worked out for you. You may want to drain, and re-fill the other tube to insure there is equal fluid in both. No surprises in compression that way.
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Way to go! I'm very glad you were able to DIY! Good advice from Zombie on changing the oil in the other leg, if you didn't already!
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A good rule of thumb with how much for oil in a conventional fork is 4 to 6 inchs from the top of the tub to the oil level with the spring out and the fork fully compressed
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...i'm starting to hear a lil noise during heavy or abrupt fork compression from time to time...
..like a rough slushing noise...
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The oil is most likely cavitating! Just needs an oil change!
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...it's probly overdue...41,000 km...lol... ;D
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I'd say so! ;) The hardest part is figuring out the correct oil volume. While your doing the oil change it's a good time to consider fine tuning which can be done through oil volume and weight.
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I'd say so! ;) The hardest part is figuring out the correct oil volume. While your doing the oil change it's a good time to consider fine tuning which can be done through oil volume and weight.
..educate me.............
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Place your right hand on the screen...
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Place your right hand on the screen...
...kaaayyy...now what...
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Now. . . Bam. . . Here ya go!
My experience is with mountain bike suspension where most of the forks use an air spring. This is primarily where the oil volume creates a drastic change in the ride. This is due to the volume of the oil having a direct relationship with the air volume. The more oil, the less air.
These scooter forks all seem to be very simple in comparison! I'm not certain that the oil volume will have such a significant impact on performance. The main thing is to make sure you don't have too much oil, this will create a hydraulic lock within the fork at the bottom of the stroke, and not feel good at all!
The oil weight in the scooter forks will allow for a good deal of adjustment. The heavier the oil the slower/stiffer the compression, but also the slower the rebound, as the two circuits are not independently adjustable. From what I discovered in trying to find oil volume/height for my Vento fork is it seems most of these forks use 15w oil. Some also specify ATF which is equivalent to 15w. I would recommend using specific fork oil though, it contains anti-foaming agents to control cavitation. ATF contains these also, which is why it can be interchanged, I've always just stuck with fork specific oil. Plus fork oil is available in different weights for tuning purposes, you can also mix weights to get a "custom" weight. Say equal parts 15w and 10w = 12.5w.
Hope this helps! Let me know if I can answer any questions for you! ;)
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Bam!!!~!!!!!!
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...and BAM!!...there it is....fork tuning 101....
...ur th' man shaka :o
..imma get out the old service manual and scope it out...