Changing Suspension Oil For Front Forks On A Dirt Bike – Part 1

Today I’m going to be changing out the oil in both the forks and the rear shock, this should be done in about every 30 hours. I split this post in two so that it is not too lengthy. This is part one of this post, I’ll be showing how to change the oil in the front forks only, part two will be for the rear shock. To start off we’ll just need basic hand tools and then, later on, we’ll need a few specialty tools as well.

The first step is to remove the front axle nut and then we’ll loosen the fork pinch bolts and remove the front disc cover bolt as well. Now we can slide the front axle out and remove the front wheel from the bike. The fork guards and the front brake caliper will need to remove the forks next.

Before we remove the forks from the bike we’ll need to loosen the fork cap and the fork inner cartridge and so on my bike the bar mounts are in the way of getting a fork cap wrench in there to loosen the fork cap so I’ll need to remove the bars and a bar mount. If you have stock bar mounts you won’t need to do this, there’s enough room to get a fork cap wrench in there to loosen the fork cap.

So if you do need to remove your bar mounts you’ll just loosen the nuts on the bottom side and remove the damper rubbers and then the bar mounts will just slide right out of the triple clamp. Now that there’s room for a fork cap wrench we can loosen up the inner cartridges and the fork caps. After that, we’ll just loosen up the triple clamp bolts and remove the forks from the bike.

If you’re having trouble getting the forks out of the triple clamps just twist the fork and it should slide right out of the clamps. I’m going to be showing the process for only one fork changing the oil and the other fork is the same exact procedure. Before we start disassembling the forks we’ll need to back out the compression and the rebound adjusters all the way and make sure to write down the amount of clickers you had in those.

So when we get the forks back together you can just set them back to your original setting. Now we can start taking the forks apart. So the first step is to loosen the fork cap all the way and slide down the fork tube and pour all the oil out and do a drain pan. Then we’re going to put the fork lug into a bench vise and make sure to wrap a rag around the fork lug so it doesn’t get damaged when you’re tightening it in the vise.

We’ll need the fork and a vise so we can loosen up the inner cartridge assembly. So the bolt on the bottom of the fork will need to be back down. Once that’s loose we can compress the fork and insert a wrench so it holds the cartridge out then we need to put another wrench on a lock nut and then get your socket assembly and so just turn those against each other and it’ll loosen the rebound adjuster on the bottom.

Once the bottom bolt is off the fork we’ll need to remove the rod as well. After that, compress the fork again and remove the wrench so the cartridge goes back into the fork. Now we can remove the fork from the vise and bring it back over the bench where we will remove the inner cartridge assembly from the fork. The next step is to remove the cartridge from the fork damper, you’ll need a fork cap wrench for this.

So pull the cartridge out and dump all the oil into a drain pan. As you’re dumping the oil out pump the damper rod and this will remove all the old oil from the damper. Now it’s time to put new oil back in the damper. The oil capacity for 2011 is 8.3 ounces but the oil capacity for every other bike varies so make sure to check your manual. To bleed all the air bubbles out of the oil, pump the damper rod several times.

Once you’ve done that we can insert the cartridge back into the fork damper so try to insert it at an angle so air escapes and to get the cap all the way down I found that it kind of helps the pump the damper rod and this will bleed out a little bit more air. So just snug up the cartridge, you don’t have to tighten that up all the way as we’ll tighten it up later. To make sure the damper assembly works properly, compress the damper rod and let it rebound on its own.

If it doesn’t rebound then there’s probably air still on the damper assembly and you’ll need to bleed that again. Now we’re going to put the fork back into the vise, and again make sure you use a rag on the fork lug so it doesn’t get damaged. Compress the fork so the damper rod pops out and put a wrench in there to hold it out then we can insert the rod back in the damper and install the rebound adjuster.

After that tighten the adjuster against the lock nut and then torque it to 16 foot-pounds. Press the fork and guide the damper rod slowly back into the fork so you don’t damage the threads. Then tighten the center bolt down, the torque specification on that is 51 foot-pounds.

Now we can add new oil to the outer fork. The minimum oil capacity is 10 ounces if you want the fork to be a little bit stiffer you can add up to three ounces extra so the maximum capacity is 13 ounces. Once you’ve added the oil you can slide the fork tube back up and tighten the fork cap down. Now it’s time to set your compression and rebound adjusters back to where they were before.

The final step before putting the fork back on the bike is just to wipe all the excess oil off the outside of the fork, it’ll just be easier to work with when it’s clean. So slide the fork up to your preferred fork height and tighten the fork clamp bolts. The torque spec on these pinch bolts is 15 foot-pounds. Once the forks are torqued into the clamps you could tighten up the fork caps and the cartridges.

If you had to remove your bars and your bar mounts, now it’s time to reinstall those on the triple clamp. Next step is to install the front brake caliper, make sure you route the brake line on the inside of the fork. The torque spec on the caliper bolts is 22 foot-pounds. Now we can install the fork guards and the front brake line guide onto the fork guard. Before reinstalling the front wheel make sure to grease your front axle.

When putting the front wheel back on the bike make sure to line up the brake rotor with the pads before you put the axle through. Then we’re going to snug up the front axle nut, don’t tighten that down all the way yet. The left side axle pinch bolts will need to be torqued, the spec on those is 15 foot-pounds.

Once those are torqued then we can tighten the front axle nut all the way, the torques back on that are 65 foot-pounds. After that, we can put the disc cover bolt back in. To get the front forks aligned, spin the front wheel and jam on the front brakes and then take the bike off the stand and compress the front forks.

You got to make sure the right side axle pinch bolts are loose when you’re doing this. The last step is to torque the right side pinch bolts, the spec on this is 15 foot-pounds.

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