THE FRONT FORK

NOT THE TYPE OF FORK YOU TAKE TO DINNER

   There is not a lot that can go wrong with the front fork assembly providing you don’t go around driving into things that don’t yield the right of way.  Assuming you need to replace or repair the front fork, this is how to go about it. 

   You need to raise the front wheel off of the ground.  You can use the centre stand, then putting weight on the rear of the bike, lift the front wheel free, then place some sort of object under your frame (or deep sump oil pan if you have one) to keep the front wheel raised up. 

   First of all you need to disconnect the front brake cable, and then remove the front wheel.  Remember the axle is a L.H. thread.  Remove the handlebar assembly and the risers from the top triple tree.  If you have a dashboard, it will also come loose so try not to tear out the wiring that goes up into it. 

   Next you need to remove the steering damper (handlebar shock absorber) by simply unscrewing the wing nut (that’s the tap thingy made of black plastic that is not a wing nut at all).  Remove the steering damper assembly and put it all back together on the shaft and put it aside until later.  Now you will probably notice that there is a piece of metal under the fork stem nut that is bent up to prevent it from backing off.  Take a drift pin and hammer the metal piece flat, and then you can remove the fork stem nut (steering column bar).

   There are two great big nuts left holding the top triple tree in place.  Each of these nuts screws down into one of the fork tubes.  Remove these nuts and the washers that are underneath them.  Now you can tap the top triple tree free from the front fork.  It might be necessary to use a long drift, and be careful that you alternate side to side to prevent the tree from binding.

   If you are going to remove the front fender, you remove the bolts which attach the front fender to the fork tube casings, and the bridge of the steering column.  If there is a bracket attached to hold your brake cable in place, remove it as well.  While you are at it, remove the bolts that hold the headlamp into the casings on the fork tubes.  I usually remove the headlight ring, and unplug the wiring to the headlight bulb and other little lights inside the headlight casing, and put the whole assembly aside. 

   Undo the remaining nut on the fork stem that holds the thrust bearing in place, and remove the safety washer.  It is suggested that you hold up the front end with one hand when you do this so that the whole thing doesn’t come crashing down onto your toes.  Now you can remove the upper bearings and race.  Don’t lose the little ball bearings, there are 24 of them.  I try to have a small reseal able plastic bag available to put them into so they don’t get lost. 

   Now you can pull down the entire fork assembly until it is free from the neck of the frame.  Be careful not to lose any of the ball bearings that go into the lower race, there are another 24 of them.  I put them into the same plastic bag as the top 24 as they are all the same.

   Before you try to put the front end back onto the motorcycle I find that it is best to put a thin coating of synthetic disc brake wheel bearing grease onto the race, then coating each ball place it into the race.  The grease will assist in holding the balls in place when you put the neck post back into the steering head (neck).  When you tighten the front fork top bearing race and crown nut, torque the nut to 8-9 kgf (17.6-19.8 PF), then ease the bearing nut off about 30*, or ½ the side.

“Pg 46 of MT16 "Operation Manual", 2nd paragraph says, "...check the
number of balls...(there must be 22 pcs. in each of them)." But, the
"Repair Manual" says on pg. 28, "See that all 24 balls...".
apparently some of us have more balls than others. :)”

THE FORK BLADE

A partial disassembly and repair of the front fork is possible without removing the entire assembly from the motorcycle.  To disassemble the fork blade (fork tube and inner spring assembly) you begin by removing the nut which attaches the fork blade tube to the traverse (top triple tree).  Pull up the shock absorber rod a bit and ease off the rod lock nut and screw the attachment nut out of the shock absorber rod. 

   Insert the front axle into the fork blade end (lower leg) and screw out the gland housing assembly.  Remove the lower leg from the tube along with the shock absorber and the inner spring.  Have an oil pan ready as this will allow the fork oil to drain out.  Next you will remove the fork blade tube lower bush attachment spring rings, along with the lower and upper bushes.  Detach the gland housing assembly and ease off the bridge coupling bolt nut some two or three turns.  Take the fork blade tube out from the bottom.  To make the job a little easier it is OK to screw the coupling nut on the tube end four or five turns.  Now you can knock the tube out of the traverse cone by lightly striking it with a rubber hammer. 

   Now that the fork blade assembly has been removed it is possible to wash the parts with solvent or kerosene.  Carefully inspect all the parts for wear or damage and replace any defective components. 

   To re-assemble the fork blade assemblies first coat the friction components with a light hydraulic fork oil.  Use the fixture to mount the gland housing on the tube.  When you screw the shock absorber rod into the coupling nut be sure that the gap between the upper spring end and the rod nut (axial clearance) is between 0.2 -0.5mm.  Before you replace and tighten the fork blade tube attachment nut fill the tube with hydraulic fork oil to a level of 130cm.  Now snug up the fork blade tube attachment nut with the washer in place.  In tightening the coupling nut to fit tightly into the cone linkage in the top triple tree, ease off the coupling bolt nut and draw it tight after the coupling nut will have been tightened up.

FRONT FORK SHOCK ABSORBER

   Unscrew the shock absorber housing attachment bolt in the fork blade end lower part, remove the shock absorber washer and seal washer provided under the bolt.  Remove the shock absorber assembled with the spring.  Undo the shock absorber upper nut and remove the upper end from the spring.  Remove the spring, unscrew the shock absorber tube upper end and take out the rod.  Wash all the parts in solvent or kerosene and inspect them for wear and damage.  Replace any worn or defective parts.

   Assemble the front fork shock absorbers in the reverse order.  The shock absorber housing pin should be received in the fork blade end hole, while the aluminum seal washer to be placed under the shock absorber attachment bolt washer should fot tightly against the end to ensure required tightness. 

   The shock absorber fitted in the fork blade end should be arranged concentric on the end tube inner surface.  Lack of concentricity of the shock absorber tube upper end should not exceed 0.5mm.

REPAIR OF THE FRONT FORK

   Check the condition of the following parts and their mating surfaces.

1)      Front fender and casings for mechanical damage and cracks.

2)      Traverse and bridge for cracks and bends.

3)      Fork blade bushes for wear on friction surfaces

4)      Fork blade tubes for bends, cracks and wear of friction surfaces.

5)      Thrust bearings for cracks, scores, dents on races.

6)      Glands for working edges

7)      Rod, spring and plunger.

   Refer to chart for clearances and tolerances of mating parts.

   Admissible wear and clearance of mating parts