Yesterday I decided to change the fork oil in my 04 Ultra Classic. My service manual said that 03-05 models are bothe cartridge type forks and they can simply be drained and then refilled from the top. Not so simple since the fairing and radio must be removed to do this. Also my bike does not have the air shock fittings. So I got the bike appart and then drained the fluid. But to my surprise when I went to refill the left fork I could hardly get any fluid in it. Apparently after reading several different threads here, my bike has a cartridge on one side and non cartridge on the other. Now according to the service manual I have to completely remove the fork and disassemble to refill the fork fluid. I did not accept this as my only option so I found a different way. I discovered that the pump that I use to refill the lower end fluid on my boat has the same threads as the fork drain plugs. Anyway I thought I would give you all a quick description of how I did it. I wanted to make sure that there wasnt any problem with doing it this way.

I started by pulling the plugs and sitting on the bike and pushing down on the forks to drain as much fluid out as possible.

I then placed the bike on the lift and after removing the fairing and radio, I removed both of the hex shaped fork end caps.

I then attached the hand pump hose to the drain hole and pumped in 10 ounces of fluid. I actually measured out about 10.2 ounces because the pump won't get every drop out of the bottle. If any one could chime in on the correct amount I'd appreciate it. The manual was pretty vague. ended up going off of information I found here.

Once I had pumped the fluid in, I reinstalled hex shaped fork caps.
That kind of created a vaccum to keep the oil from surging back out although a little still did shoot back out. I just put my finger over the hole as soon as I could get the pump hose unscrewed and replaced the drain screws.

It is very cold and snow on the ground here in central Illinois so no test riding yet. The bike feels pretty sturdy in the garage and there are no leaks that I can detect. I would appreciate any input you all mite have. If enough people tell me that this was completely wrong I will find another way or perhaps pay the dealer which I hate to do, but would hate a firey crash even more.

Thanks in advance

 

FWIW to owners of '06 and later FLH models, I did a write-up on changing the fork oil on these here. Discussion of the actual job of changing the oil starts on Page 3 of that thread.

My bike has damper valves installed (stock for EG/RG only, not RK), which apparently keep the fluid from going in all at once. I found that adding a few oz. at a time followed by pumping the forks several times allowed all the oil to go in from the top. Maybe that would work with cartridge forks as well. When pumping, the sound changed when all the oil was installed for each cycle.

Also, as was cited in the write-up, I used SE Heavy fork oil (not Extra-heavy racing), which firmed up the front-end a bit, improved control, and eliminated bottoming. The net-effect was positive. Some have mixed Type E with the SEH, and I may try that next time just as an experiment.

 

The amount of fork oil is not really the number you need to factor in , it's the oil level/ air chamber volume. This number changes how quickly the forks spring rate rises due to air pressure build up inside the tube. Because each oil change will leave different amounts of oil inside the legs you have no idea what the oil height is inside the leg unless you measure it because when you put 10 ozs in you don't know what was still left inside. That is why to accurately do an oil change the fork must be removed and oil height measured . I know this is a pain but if you don't know the height in both legs you don't know what you have done to effect the spring rate of your forks. Due to the small volume of the forks, a small change to the height can make a big change in rate.

 

Thanks guys! I think I'll go ahead and redo the process on my next set of days off. If anything just to put the heavier SE Heavy fork oil in. Iclick thanks for the link to your post I read through it and found a lot of usefull info. Bike has about 28000 miles on it so may just go ahead and tear the forks completely down. I Read through the service manual and although the process seems a little time consuming its not that compicated. Nothing but time on my hands waiting for warm weather anyway. I'll keep you posted.

 

Setting fork oil level - this makes a big difference in how your bike reacts when it bottoms out. The fork oil level determines the size of the air chamber at the top. The amount of fork oil is only an estimate. It is the level of the oil form the top of the compressed fork that counts.

Buy a 99cent Turkey baster. Mark the distance from the tip of the baster for the recommended oil level, your service manual will have this listed, eg. 5.3 inches.

With the springs removed and the fork fully compressed, pour in the fork oil to say 4 inches of the top if the desired oil level is 5.3 inches. Uncompress and compress the fork leg several times to work out air bubbles. Drop the turkey baster into the fork tube up to the marked line. With the fork leg fully compressed suck out the oil, until you are sucking air, return the unused oil to the container from the baster. Ideally you should be doing this with the fork tube removed from the triple tree and held vertically. The exactness of the fork oil level makes a big difference in ride especially when bottoming out. Once you have the desired oil level drop in the spring, washer, preload spacer, washer and install end caps. Reattach to triple tree ensuring fork height set correctly.

 

thanks for the write up. Am doing the change now. But, you weren't kidding when you mentioned the smell of the old oil. Damn, had to air out the shop after that one!!

thanks again for the tip.

 

I do many forks. I wholeheartedly request you members to try taking your forks completely apart but dump the oil in a container first for examination. This is one of our members oil after 10K mi or less.


Once you take the forks apart completely wash them with a solvent than let the dirt and debris settle, skim off the clear solvent and look what is left.


Look down the inside of the fork tube and see how dark it is with a black material. Wad up a paper towel like a rifling patch and swab it once than look at the paper towel. This takes several times to clean it. All of your fork parts look like this.

For the fun of it next squirt in some contact cleaner of brake cleaner and let it drip onto a white paper towel or into a white plastic cup. That is what your forks are covered with.

Look at your bushings after 10K~15K miles. Look at a brand new set and you will see a clear coating over them (Teflon). Once your fork tubes or sliders wear through this slippery coating you are than into the brass which you do not wish to be. This is a members Dyna with less than 15K mi. Was he surprised!


And a HDF member's Street Glide with around 12K mi.


Your bushings will wear out rather quickly , this is due to the large rake of the fork tubes and heavy weight found on a typical Harley and not a lesser degree of fork rake found on a Sport Bike. Just be aware of the problem.