Harley Fork Oil Service

Next in our service we're gonna change fork oil on our Sportsters. Harley's used the number of millimeter diameter forks throughout the years, the newer bikes mostly use 39 millimeters. That's what this is. I'll do this service on only one side, but it has to be done on both sides of the front fork assembly during any fork oil change. To start, I wanna use a hand impact, with a Phillip style bit and wrap the drain screw loose. You'll know that there's a brass washer on the drain screw, again, check its condition. Once the screw's loose, I'll pull it out of there, you'll see there's fluid behind it so have a clean drain container ready. I stress using a clean drain container because you'd like to see what comes out at a fork assembly, how it's been running in service. You'll know I've got to center lift style Jack under the motorcycle, once the lower drain screw's removed Mark's gonna raise our center lift Jack, this is just to take the weight off of the front end while I loosen the top cap. That's good. You got a new clean towel here. That's good. I'm gonna use Jim's tools offers a nice low profile for tube cap remover, and along here below the ratchet. I'll start to work the thread out, I wanna make a note again, how important it is to get the correct factory service manual for your model and year specific. Some of the Sportster front ends have a spring preload, which means this cap will be under pressure when you remove it from the fork tube top, make sure you hold onto it. With the fork tube cap loosened, I'm gonna use the Jim's tool on a short extension in the palm ratchet. Again, I have to stress these front ends are preloaded with the fork tube spring, not only do I have tin, not only do I have painted pieces covered, but I'm also gonna keep a nice firm grip on this cap as I loosen it. Never take for granted when dissembling one of these fork tubes that it's not under pressure. You'll see once I remove this, that it pops up. You're gonna actually get a nice view now of how much preload you're contending with. Don't let this cap get away from you, it'll surely chip you pain. You also know how much more the fork oil now that it has a clear drain path advent itself right out, and the oil comes out of the fork tube easily. I usually wait for the fork oil to stop, and then I'll have Mark just lower, you'll notice the spring starts to extend out of the top fork tube cap, and the rest of the oil will continue out. Do not lower your motorcycle too much. The lower fork trees will contact the front fender. Again know your bike, use your manual. Always have a friend with you. Although it's a Sportster model, it's still a 500 pound motorcycle that you've got your fork oil out, you're dealing with your steering mechanisms. They're definitely safety orientated. Make sure you know what you're doing. Once all the fork oil's drained out, I'll have Mark bring the lift back up, it'll relieve pressure, not only on the front end, but on the internal spring mechanisms. Like all sealed surfaces with a sealing washer or rubber O-ring anytime you service it, clean it with a little parts cleaner, and I like to put a double of Teflon paste on it. It's a very small drain screw. So naturally thread it in by hand, tighten it down snugly, make sure that thread is enclosed. And then you can torque it to 17 inch pounds. Again, make sure you're using inch pounds where there's an inch pound specification. With the lower fork drain screw re-installed into the slider assembly, I'm now gonna refill the fork oil. I keep an empty container from fork oil, so I can pre-measure the 11.6 ounces did this particular model needs, check your service manual always install just the correct amount of fluid, don't overfill the fork assembly. You'll blow a fork seal out. From a sealed container of fork oil, I'll pour 11.6 ounces. Now that we have the pre-measured amount of fork oil, I'm gonna pour it back into the front fork assembly. You'll note the spring is sticking out, so make sure your funnel goes down into the fork tube. You'll have to apply slight pressure, pour the fork oil into the funnel, make sure you give it time for all of it to come out of the container that you're pouring from. You wanna use an exact thing amount. There are other methods in the service manual, you can check the manual for those methods this is my preferred way to do it. With the pre-measured amount of fork oil poured back into the fork tube, I'll remove the funnel and I'm gonna prep the top fork tube cap. Little parts cleaner, we'll clean off the threaded portion, it's an O-ring sealed surface, I'll reinspect the O-ring, just to touch a tough one paste, again you don't need a lot, it'll spread right around on the threads as you go in with it. This is an ideal case when you need help this is a preloaded spring. Mark's gonna get up top, he should use the Jim's tool and a palm ratchet, I'm gonna help him put this down on the spring, it usually always takes two people they get that started nice and straight. Once it started, you'll now run it down with the palm ratchet making sure the O-ring stays in place, run it down just til snug. Always keep a hand on your tools when you're working above the painted areas even though they're covered. Once it's down snug I'll grab a foot pounds torque wrench, and I'll tighten it to 58 foot pounds. We've now completed a fork oil change on the left slider side of the motorcycle. This procedure should be repeated on the right side of the motorcycle, in order for the service to be complete.