Seal surgery

Author: Words by Geoff Walker Photos by Hot Tub

Blown a seal and feeling depressed about it? Well turn that frown upside down with Wakker's wonderful seal-servicing walkthrough

You know that sinking feeling when you go to roll the weapon out on a Sunday morning and see a pool of fork oil on the garage floor? It sucks - and winter is the time of year when your fork seals are most likely to blow.

The very latest bikes are coming to us fitted with twin-chamber forks. The longest running twins are the Showa forks which have been fitted to the Hondas for a few years and now come stock on the KX250Fs.

Seal servicing on this type of fork is possible with a couple of special tools. You'll need a fork top spanner, 47mm seal driver, a small plastic bag and an internal rod holder as well as some form of buzz gun with 21mm socket to undo the base holder for the internal chamber. You'll also need a 21mm and 17mm spanner as well as a flat blade screwdriver to perform this fork surgery. Other equipment needed is a sturdy bench and vice, a measuring jug, a heat gun and an oil catcher.

The special tools are available from Motion Pro and also your local dealer can order tools for you from the manufacturers.

	step 1 With your forks removed and very clean, the first step to seal bliss is to check each clicker to see how many clicks out they are. To do this you need to wind them in a clockwise direction making a note of how many clicks you hear before the screws bottom out. For instance if you hear 12 clicks on your compression screw and 14 on the rebound the settings would be comp 12, reb 14. Write these down so when you finish both legs will be the same as before.
	step2 The top of the fork can now be loosened with the special spanner. If you do not have the tool then you can gently clamp the top in the vice and turn the fork body to loosen. You may need to heat the leg slightly to make it easier to loosen if the area you are working in is cold.
	step3 The outer leg can now slide down and the fork bottom must be clamped in the vice. Be careful not to damage the fork bottom. Using a 21mm socket undo the bottom holder. Again, you may need to heat this area with a heat gun to make it easy to loosen. It is really important to make sure you use a good quality socket on this part as it is easily damaged.
	step4 With the palm of your hand on the top of the fork push down. This will release the oil from inside the fork as the fork bottom is pushed out of position. The fork holding tool can now be slotted into position so the bottom can be undone from the base of the internal chamber shaft with the 21mm and 17mm spanner. Simply hold the 17mm in place and undo the 21mm part.
	step5 The base holder can now be taken off and the rebound adjuster rod from inside the shaft will slide out. Remove the holder and slide the internal chamber and spring out of the fork body and place somewhere clean and safe.
	step6 Using a flat blade screwdriver carefully prise the dust seal out of position and clean the area around the inner seal to reveal the holding clip. Again using the flat blade prise the clip out of its holding position.
	step7 Gently heat the outer fork leg around the seal area to make it easier to split the fork apart. Using a firm grip on the outer leg slide and extend it up away from the lower fork leg. You will feel it try to come to a stop. Tap the outer leg at this point and the leg will come apart into two sections.
	step8 Remove, inspect and clean the bushes as well as the entire sliding surface of the lower chrome leg. Stone chips on the chrome will tear the next seal you fit. If there are chips present on the chrome, use a small grinding stone or a tiny file and emery paper to smooth away the problem areas.
	step9 With all parts clean it is time for re-assembly. Lightly grease the inside lip of the new seal and the dust seal. If you do not have seal-grease use some racing grease mixed with a little fork oil. Place the plastic bag over the top of the fork leg and slip the seal gently over the top of the leg making sure you don't cause any damage to the seal. Make sure you put all parts back in the order they came off in. Dust seal, clip, oil seal. Take the bag off and replace the two bushes in order.
	step10 Replace the outer leg onto the lower leg and push the parts into place by hand, leaving the dust seal and clip at the bottom of the lower leg. Now put the seal driver into place and tap the seal up into the body of the outer leg. You will feel the bushes and seal knock into place. Replace the holding clip into its position to hold the seal in place and push the dust seal into place with your fingers.
	step11 Drop the spring back inside the fork assembly and replace the inner chamber. Push down on the inner chamber and secure in place as it protrudes out of the bottom of the lower leg using the special holder. Slide the rebound adjuster rod back into position. You will feel it find home when it slips into position with its top holding position. If you do not refit this part correctly the rod will be damaged at the next stage of assembly. Screw the bottom holder into position and tighten into place. The special holder can be removed and the bottom of the fork will slip into place, tighten firmly into position.
	step12 Fill your measuring jug with 360ml of 5wt fork oil and pour into the fork body. Check your owner's manual for adjustable range on oil - 360ml is an average amount. Normally go 20ml less for softer feeling and 20ml more for a little harder feeling.
	step13 Lift the outer body and fit the top cap into position. Now reset the clickers on the leg, refit the fork into the bike and be proud of yourself.

Seal surgery

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