Changing Fork Oil on 1999 GL1500SE


Information and questions on GL1500 Goldwings (1988-2000)
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RockportDave
Posts: 189
Joined: Sat Mar 31, 2018 9:39 pm
Location: Rockport Texas
Motorcycle: 1999 GL1500 SE

Changing Fork Oil on 1999 GL1500SE

Post by RockportDave » Fri Jul 06, 2018 7:30 pm



Just a few more items on the “todo” list for our bike to be what I call trip ready. Time to change the fork oil.
This How To is for a 1999 GL1500SE with schrader valves in the fork caps and stock (I presume) springs. Progressive springs will need a different amount of oil and air gap from the top of the fork caps to the oil level.
I already have the brake rotor covers off, so I started with setting the bike on the center stand and draining the old oil. I bought two cheap drain pans at the auto parts store and put them under the forks.


I took out the drain bolts on the anti-dive units and the oil started draining slowly. It still had some red tint to it, but mostly gray.




Be sure not to loose the copper sealing washers on the bolts.
Now, here is what NOT to do. Without thinking, I removed the schrader valves from the top of the forks.


It makes a big mess when the oil comes rushing out. Good thing we have cats, I quickly put kitty litter down to catch and soak up the oil.


After letting the forks drain for about 30 minutes, I taped some cardboard from a shoebox around the forks to funnel the oil into the pans.




I used Honda SS-8 10 WT fork oil and poured about 3-4 oz into each fork after re-installing the drain bolts and then bounced the front end about 15-20 times. I drained the oil again and it was clean and red.
I bounced the front of the bike with the drains out to get all the old oil out and also blew low pressure air into the top. I let them drain for about 30 minutes and re-installed the drain bolts.
I used a pointed bottle cap from a bottle of rear end oil and filled each fork with 12 oz of oil.


I bounced the front front end again about 15-20 times and put the bike back on the center stand with a floor jack under the engine to raise the front tire off the floor and extend the forks to the maximum.
Using a dimension I got from another web site, I cut a length of small plastic tubing and attached it to a 35 cc syringe I bought from a feed store and taped it to keep it from coming off. I slide a larger piece of vinyl tubing over the plastic tubing and taped it in place at 14 3/8” (the dimension called out was 14.3”).


I inserted the tube through the schrader valve hole until the vinyl tubing bottomed out on the top of the fork cap and pulled the syringe. No oil, so I added 2 oz to each fork and re-inserted the tubing. I pulled the oil from each fork until no oil could be pulled out which should give me an even 14.3” air gap on each fork.
Before lowering the front wheel to the floor, I installed the schrader valves so there will be positive air pressure on the forks when they are holding up the front of the bike.
A good test ride over small bumps at 30-45 mph, a bridge at 55 mph and highway at 75 mph, the front feels a lot smoother, but not mushy.
Dave


1999 GL1500SE 5th Goldwing through the years

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