Dirt Bike Fork Oil Leak Fix [Video]

Dec. 13, 2011 By Jaime Hernandez

Do you have a leaky fork on your dirt bike, slowly spewing oil down to the wheel and floor? Before you spend hundreds by getting your forks rebuilt, we highly recommend you give the Seal Mate from Motion Pro a shot. We did and it fixed our leaky MX bike’s fork in just minutes.

With full-length dust covers going away on MX dirt bike forks in the ‘80s, some say it made modern front fork suspension more vulnerable to the elements. The funny rubber accordion dust covers were replaced by sexy small ones on inverted forks (a.k.a. USD or upside-down forks). 

We knew it was getting bad when fork oil showed up on the floor and all over our front disk brakes and wheel.

As with all little sexy things, these new inverted forks need extra attention. Even with the regular hose down, enough dirt accumulated on our RM250s front forks. We’ve been riding on some dusty trails lately, trying to keep up with Off-Road.com Editor Josh Burns.

At first we thought it might be a bad fork oil seal, and that the forks would need to be rebuilt. After some research and learning about Seal Mate, there was a good chance that dirt and grime was keeping the oil seal from properly sealing on the fork tube. 

Seal Mate by Motion Pro: This simple-yet-effective tool is a great fix for oil leaks on your dirt bike or motorcycle’s front fork suspension. 

Before taking the front half of the bike apart, we decided to give the Seal Mate a shot.  At $5 for the Seal Mate tool, you can’t go wrong to give it a shot. A fork rebuild will run you in the hundreds at any reputable motorcycle shop.

Here is an overview of the process:

Clean off the area and remove dust seal. You can use a small screwdriver to get this done.

Since our RM250 is over 10 years old, we decided to only remove the spring ring off the dust seal to gain access to the oil seal. We weren’t sure if the old dust seals would come off without tearing. If you can, it is better to remove the dust seal, as it will give you better access to cleaning and servicing the oil seal. The alternate worked for us.

Seal Mate recommends using contact cleaner to clean off the dirty fork area under the dust seal. Using a clean rag, wipe down any dirt or grime that comes out.  Here you can see small particles of dirt coming out of the fork (right).

Next, carefully insert the Seal Mate tool, hook-end first until it is approximately 1/2" deep.Gently rotate Seal Mate around fork tube making sure that the hooked-end leads.

Grab the front brake and compress (pump) the forks several times. Wipe away any oil from the forks until the oil seal sits in place. Now you’re ready to ride again!

Just a few minutes of cleaning and re-seating the oil seal made our dirt bike good as new. No more fork oil leak. 

We highly recommend this product to anyone experiencing a leaky fork. It works on dirt bikes and other motorcycles with inverted forks. It’s worth every penny and well worth a try before rebuilding your suspension forks. It’s the easiest and fastest way to get back on the saddle.

Check out this video from Seal Mate’s website, which demonstrates how easy it is to do – and it really is!

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Seal Mate

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