how can i rebuild my front forks

hi was thinking of rebuilding my front fork on my nrg extreme cos both seals have gone and they havent had any fork oil in since ive had it (2 years) how would i go about fitting new seals and fork oil ? any one done this before ? thanks

 

since i have just re built my TRK pailio forks i think i can offer some assistance
a few tools you may need; usually a 8mm allen key, but in somecase u make need a 8mm allen key adapter which is long and can fit in a impact wrench.

Refer to the manual on what SAE oil you will need. Also in the manual if should tell you what size seals you will need. if the dust seals look ok you can leave them alone, but if they are a bit beat up, change them to.

after you have found the right SAE type and seal size, go on ebay for your parts, seals no more than £10 and same with oil. Since your dealing with scooter forks, dont go buying a 1liter bottle of oil its just a waste. when i did mine, the manual said to only put 90ml in each fork. so look for small bottle by a good brand; castrol, motul, shell someone like that.

most forks are a little different from one another, but usually disassemble the same way.

1. your best off doing one fork at a time, since its your first time.
2. take a fork off the ped. this is usually done by undoin a nut on the yoke of the front end. (you may have to use a flat head screw driver to open the yoke abit and tap the top of foke gentally to help it out)
3. once out, prep your self a CLEAN work area. (getting dirt in the fork with just mess them up and you will have to start over again)
4. most forks have a 8mm allen screw at the bottom if there RSD or top if USD forks. undo this screw. you may have to hold both the fork stanchion and the outer fork to stop them spinning with you undo the bolt. (get some one to hold them or just use a impact wrench and rest fork between legs to support)
5. when you take this bolt out make sure you have it pointin upwards and that you are still holding the fork.
6. get an old container to empty the old fork oil into. let it drain for at least 15mins to 30mins.
7. once drained, part the stanchion from the outer fork, sometimes you may have to give it a good few yanks to part them. look on youtube how to do this, its like a slide hammer method.
8. give the stanchion a good clean (usually petrol or white spirit or what ever the manual says you can use. check for pitting, dents and rust. if it have really bad pitting or dents you make need a new stanchion. if have some rust, use some wire wool, emery paper or a dremal tool to get rid of as much as possible.
9. in the stanchion will be the spring, damperning rod and a centering bush. the bush is what the allen screw goes into, dont lose this or your forks will not got back togeter.
10. you will now be able to remove the dust seal from the outer fork. try not to damage outer fork while taking it out. the next thing to take out is a small circlip, do not break this or lose it, it is sometimes hard to get a replacement. after this is out remove the oil seal, again be careful not to damage the outer fork. this can be hard to take out.
11. remember which order you take things out, they will need to go back in the exact same way.
12. put you seal you new seals back in, it is a tight fit, so it can be hard to put back in level with out damaging it. you can use a seal installer tool, or use the old seal and a socket big enough to hammer the new one in. ( gently tap the new seal in, then put the old one on top followed by the socket and tap it the rest of the way in till it is seated)
13. you will usually fill the fork up will new oil, by pouring the required amount into the damperning rod in the stanchion.
14. That basically it, just put it all back together, the same way it came apart.

Search youtube for videos on how to take apart the forks and to learn the names of each parts. Also try find the manual for your forks online, since the manual will usaully give you part numbers and torque values for the both.

Happy to help

 

It's a waist of time rebuilding upside down piaggio forks, just buy new ones. When you get the new forks, drill a small hole near the top of each fork leg and spray in chain lube/ silicone spray, anything like that. It will leak out straight the way but it will keep everything lubed up.