[Fork Seal Change for FZ750] by Vesa
| First of all, I might mix the U.S and U.K terminology here, I apologise that... There are several other sources in the Internet where you can find additional help and perhaps some better knowledge, too. See some general guides and pictures e.g. at http://www.dansmc.com/forks.htm The fork seal change is not that hard to do. This guidance is for the original FZ's but it is applicable for similar assembly. It might differ though if you have upside down front end. It is easiest to take the whole fork legs out but I assume the change can be made without releasing them from the triple clamps (yokes) as well. Here we go all the way... First of all, don't mix the parts from one fork leg to another! Also, be prepared to replace also inner low end bushings (at least mine were worn out, they're some sort of teflon coated short pipes, you'll find out what I mean when you open one leg). And don't hit or nip the legs in any phase of the assembly! Also remember to be careful when releasing the springs, don't be in-line with the obvious flight path! Put the bike on a center stand. Strip away front wheel (take also the small lock bolt away from the other leg!), brake calipers (chock the pads somehow!), mud guard and everything else that seems to be on your way when doing the job. Loose the air (if any)from the legs and drain the fork oil from the small screws at the bottom of the legs (sliders). Remember to put them back before you put new oil in... Remove/loosen clip-ons (note the small allen/hexacon screws if you remove them), loosen the bolts from the upper and lower triple clamp (there were 2 bolts at low and 1 at up for one leg). Now you should be able to pull down the legs by bare hands, you can use screw driver to expand the carrier loop and some CRC, LP-40 or similar to ease the slip (be careful, don't damage the fork tubes or clamps!). Take both legs simultaneously down for about 10 cm and remove the air connecting pipes&nipples from the top of the tubes (beware of not damaging the air seals, some lubrication may help here). After that you should be able to remove the legs totally from the triple clamps. Now check the low end of the legs (sliders). There is a large (8 or 10mm?) allen bolt that holds the darper rod. Loosen it a bit, a couple of rounds. Now remove the top end caps to release the springs (don't let it or other flying parts knock-out you and take your daddy's car off the garage...). The idea of loosening the low end bolt before is to have some tension from the springs to help the work, otherwise the nut might spin around! Sometimes this spring tension is not enough to hold the damper rod, then you need to take the spring out first and make a special tool to hold it while you twist. The tool can be anything from rod with two nuts (outer size 24mm?) locked or welded at the end of the rod to a special tool from Yamaha. I used a die-cut sparg plug tool (the outer edge of the tool has almost the size you need!) and about 100cm long extension arm with a T-handle in it. Among the spring there comes some other "stuff" out of the leg, neither loose them nor mix the order. Now unsrcew the allen bolt from the low end of the leg to release the damper rod. After this you should be able to remove the tube from the slider (now you should also see the bushings I was talking about earlier). You may need to pull here more than you expect... they should apart, though. Remove the dust cover and a circlip above the fork seal and take the seals off (mine were bit rusty, use e.g. CRC to ease the removal). Clean all parts inside and outside before the re-assembly (don't use the solvent in the rubber parts). Lubricate the fork seal with the fork oil and put it carefully onto the inner leg (tube) first, then fit the tube in the lower leg (slider) and press the seal in the seat (no sharp tools here or you'll srcew the whole thing; a large pipe not necessary either but may help; a stiff plastic drain pipe would be perfect here)! Then, put the circlip and dust cower on and so on, basically do everything that has been told here but counterclockwise (twice, you have two legs yea...). Don't forget to put new oil in the fork legs, depending the FZ model it was 404ml or 408ml 10W fork oil, wasn't it (Check this from Manuals)? That 4ml wouldn't make any difference. To get it stiffer, use 15W oil or make a mixture of 10W and 20W oils. Suit yourself... Remember also to put some air in but not too much or you'll soon blow out the seals. It takes about 2-4 hours if you don't need to spend time on searching the parts, tools, beer etc. A pair of genuine seals cost here (Finland) about $15, no worth seeking second hand ones. |