Changing the Fork Oil

A special thanks to Ken Chapin (WuzFuzz) for his permission to post this write-up to the the VentureRider tech library.

I found it hard to believe that YAMAHA states that regular fork oil changes are not needed on the 2nd Gen RSV. During my winter teardown process, I decided to open things up and have a look. Apparent right away is the fact the the forks do NOT have a designated drain. You can, however, remove the lower fork damper bolt. This bolt screws into the internal damper rod which has a rebound spring encompassing it. This bolt basically ties the internal components of the fork assembly together.

I have the benefit of a centerstand on my '03 Midnight, so it was easy to use my floor-jack to raise and support the bike so that the front wheel is off the ground. Remove the caps from the fork air valves and release any air pressure. Next the front axle has to be removed so that access can be gained to the damper bolt at the bottom of each fork. The wheel/tire can remain in where it is --- in between the forks. You will now need a 6mm Allen head socket with a long reach to access the damper bolt itself. Prior to loosening the bolt, give it a couple of raps with a hammer to break loose any corrosion that may be locking the threads. I also have the luxury of a compressor and air tools, but the bolt can be loosened with a regular socket wrench. The inch long Allen bolt with its companion copper sealing washer will come out with the fork oil draining from behind it. Have a catch pail handy as over half a liter of oil will be draining. To speed up the draining process, you can remove the Schraeder valve from the air fitting on the top of the fork. Repeat the process on the other fork.

I found the thin 5W fork oil somewhat on the dark and dirty side.............. looking nowhere near like new oil. My '03 currently shows just over 30,000 kilometers on it.

I then used my air compressor to blow down through the forks to expel the remaining oil out through the damper rod hole at the bottom of each fork. When the oil quits draining ---- I left mine to sit overnight --- you can reinstall the damper bolt and its small copper sealing washer with a little sealer on the threads. It is best to lower the front end so that compression of the forks and their inner components takes place and alignment of the damper rod meets with the access hole. Tighten the bolt securely and use a torque wrench to obtain the specified 14 ft lbs.

Refilling the forks with fresh fork oil takes a little longer but it can be done with a filler hose from a bicycle pump and a squeeze bottle or large syringe from a vet supply house or pet store. I chose to refill my forks with BelRay 15W in the specified amount of 553 cc per fork.

First, make sure that the Schraeder valve is not in the air fitting. Then attach the screw-on filler hose from a bicycle pump onto the Schraeder valve. The squeeze bottle I use is equipped with a large bore needle on the end. It is also marked for volume and I attach it to the open end of the filler hose. Due to the smaller orifice of the Schraeder valve, it takes somewhat longer to fill the forks than it does to empty them. I would estimate that it took about 10 minutes per fork to squeeze the specified 553 cc of fork oil into each tube.

When you have inserted the specified amounts, remove the bicycle hose, reinstall the valve into the fitting and preload the forks with your desired air pressure. With the 5W, I was using 5 or 6 psi, but I expect better dampening with the 15W so lower pressure ratings will most likely apply. I will have to wait until the start of the riding season (for me its next month) before I settle on an air pressure setting. For now.......... I inflated them both to 4 psi.