Suzuki (various models)

[Gixxerthou]

How to change fork oil without stripping assembly completely.

Tool required is a syringe preferably 125mm (6”) long.

I didn’t have a proper medical syringe, I just used a inkjet printer cartridge refill syringe and stuck a thin straw over the needle to gain longer range. Inside of a pen can also be used, or a battery acid drainer/leveller.

Remove forks from bike and unscrew fork cap bolt (A) fully.

Wind out compression, rebound and preload screws fully out (anti clockwise).

Offer fork to a container and invert fork slowly to allow old oil to drain out into container for disposal.

Whilst oil is draining slowly slide outer tube (3) up and down and move around at different angles to allow all sludge to drain away and leave to hang draining for 20 mins minimum.

Note a method of oil to be used is to measure the amount of oil taken from the forks and replace the new with the same amount. This method written here is proven in practice by myself and others and information has derived beforehand from various dealers and engineers. Were you to carry out this task to Suzukis manual you would need to spend money replacing seals etc.

When drained turn fork back up to the proper direction and once again rotate once more to find any dormant oil, then offer new fork oil tub nozzle to either of the two holes in the side of the spacer (1) and slowly pour new fork oil into the tube not forcing the oil too much. When the oil starts filling up to the top of the outer tube (3) slowly lift the outer tube upwards to contain the oil from spilling over as it fills up.

When the fork is full of oil slide the outer tube (3) up and down a little slowly to allow any trapped air to bubble to the top, then screw in the fork cap (a) half a turn to hold the 2 items back together and leave to stand fully upright for 20 mins to settle.

Carry out same method to other fork.

When both forks have been filled and settled fully hand tight the fork cap bolts (A) and offer them to the bike yokes and fully build bike back up.

In this next step you may need to remove the fairing brace above steering head as to allow space for adjustment.

With the bike on its rear paddock stand, place a small block of timber underneath the sump as far forward as possible and place a small jack under the bike using the timber as an anti-slip anchor and jack up 10mm just to take the weight of the bike.

Fully unscrew the fork cap bolts (A) evenly and lower the jack very slowly to allow the bike to sink pressing the outer tubes (3) downwards (this will make the inner tube and fork cap bolts raise straight up).

Be careful not to go too far as you do not want any oil to escape onto the bike (not that its harmful, just messy)

When the oil is forced near the top of the outer tube (3) take the syringe and remove all the excess oil you can get from both forks.

Lower the jack further, all the way until the forks bottom out preferably, and push the syringe in again as far as it will go (syringe will be hitting the top of the inner tube (12) this is the oil level) and as far as the syringe will go.

When both forks have met the same level you have completed the task of balancing the levels.(these levels being the same are crucial to handling of the bike)

Jack bike back up slowly and fully screw in the fork cap bolts (A)

Then take jack away and set up compression to 4 clicks in

Turn in the rebound to 4 clicks in

Set preload to 5 lines showing, these settings should give between 28mm and 35mm of static sag as required for road use.

Ride gently and adjust settings to personal preference.

OIL MEASURMENTS

Suzuki claim measuring 93mm (air gap) from top of fork oil to top of fork fully compressed.

As a safe guard levelling to the top of the inner fork tube is a good compromise and an exact balance for the enthusiast, as some small amounts of old oil may have still been trapped in the seals. This gives an estimated airgap of 100mm current to the comments of many professionals.I used Castrol performance fork oil 10W. Synthetics are also available. Some have used 5W.

Originally submitted by MadManc U.K.

Copyright The Thumperzone 2008