Voyager XII Rear Shock Oil Change

These pages compliments of Jeff Barnhill

Thanks Jeff from the Voyager community


Voyager Rear Shock Oil Change
My Voyager had started riding so rough it was shaking a lot of bolts loose. It was time to look at new gas shocks, changing the oil or having the KYB shocks rebuilt, and to add progressive springs to the front forks. Before I spent $3-500 dollars on Progressive shocks, I wanted to try and change the oil in the shocks as I've heard others do.

The Kawasaki Voyager manual made the job look complicated. I never heard of filling up a shock then draining a certain portion out. I had changed the oil in oil only shocks but not air assisted oil shocks. The air over oil shock needed a certain amount of air over the oil reservoir. The manual said to fill the shock with 390ml(cc) of oil then drain out 160ml of oil leaving the 160ml of airspace

I decided to get one of the Rubbermaid plastic calibrated measuring cup at the hardware store, drain the oil out, then put the same amount back in.

I had seen on the Voyager forums where a turkey baster was used to get oil in and air out of the shock. I had used a 2oz/60ml hospital syringe on other shocks. I filled the cup using the syringe to get the 160ml mark, the 230ml mark, and the 390ml mark. I removed the shocks and drained the oil into the empty cup. The oil level was 230ml in both shocks per Kawasaki specs, so I decided not to worry about the air space and to fill the shocks back with the 230ml oil that came out.

Getting the oil out of the shocks looked like fun since there was a tiny opening to get oil in and out of. The right shock would be easier since it has two openings. I could turn the shock upside down and blow air into one fitting forcing oil out the other. Instead of using high pressure and risk blowing a seal, I decided to use the clear 1/4" line I had used to bleed the front and rear calipers. Using a new piece of line I held the shock upside down over the cup with one hand and held the other end on the fitting and blew air in with my mouth. Worked like a charm, the specified amount came out into the cup (230ml)

The left shock with only one fitting was just a little tougher. I held the shock upside down over the cup, blew air into it, and removed the airline quickly to let the pressurized shock blow a stream of oil out. Also the recommended 230ml. Holding the shock upside and blowing air into it puts the air above the oil which purges out easy.

Filling the shocks involves filling the cup to 230ml, then draw it up into the syringe. It went in easier in the left shock with two fittings. One allowed air to escape while filling. The left shock required adding a little oil at a time, pulling out the syringe to let air out. I used a rag around the syringe to keep spillage minimal.

The only problem I encountered was not liking the 5wt oil I tried first. It was too light. I tried 10 wt a little later and it was too stiff. I went looking for 7 wt Bel-Ray shock oil that I had seen in the past. The only oil available on that Saturday was 5wt and 10 wt. From a test I saw many years ago by a friend who rode and worked for Exxon, I know the lighter weight oils(2.5,5,7,10 and 15 wt mixed near linear, meaning a 50-50 mix of 5 wt and 10wt made 7.5wt. The test was done using the centistoke viscosity standard. Oils such as 90wt mixed 50-50 with say 30wt to make a 50wt oil, the proportions are much different. But for close measurements like I said mixing the lighter weight oil mix is near linear.


The first step involves removing both saddlebags and trunk, driver and passenger seats.

Unplug the connection in front of the trunk in the sleeve. They are for the trunk lights.

Remove the two acorn nuts with the ten millimeter heads. The bolts along with the steel sleeves will probably fall out.

Remove the two twelve millimeter bolts at the rear of the trunk.

Unplug the passenger radio control plug in the pouch by the controls. The trunk can now be lifted off.

Place board under rear tire to support it while removing shocks.

Let the air out of the shocks.

Remove the left shock upper and lower acorn nuts with a seventeen millimeter head. The upper nuts use a lock washer.

The right shock has a fourteen millimeter bolt.

Remove the rear rack mount bolts. Mine are drilled out using a nut with the Markland Hitch, the standard setup screws into a welded nut on the frame.

Loosen but do not try to unscrew the crossover line on the left shock, it goes over to swivel nut on right shock. It will be easier getting off if loosened first. The line screws directly into the left shock and will be unscrewed with shock off bike.

Loosen and remove right swivel nut on right shock, it will be the rear line of the two with a twelve millimeter head. If you can get to it loosen the front line going to the oil separator. It also screws directly into shock, and will be removed by rotating the shock when removed.


Special tools needed

__Draining right shock__


I held the shock with my right hand and held the plastic hose on the fitting with my left.

The syringe to fill the shocks fits tight enough to stay by itself. I held the rag around the syringe to help stop leakage on the left shock.

I pulled it out to let air out about every 50ml.

Be careful with the o-rings on the hoses that screw into the shock.

Do not let trash or dirt get into the container holding the fresh oil. As always check your turn signals after remounting saddlebags. Make sure you plug the connectors on the saddlebags in.