How-To: Leaky Rocker Box Gasket Fix on Harley-Davidson Sportster

Have you ever been riding down the road and felt some hot oil on your leg or arm, or noticed an excessive amount of oil around your cases? It’s probably a rocker box gasket leak causing you all that trouble. 1986-2003 Harley-Davidson Sportsters are notorious for having rocker box gasket leaks. The old gaskets from the factory were poorly made in two separate pieces, over time the gaskets become brittle and useless. With one of the guys bikes here at the shop having this exact problem, Todd thought it would be a good idea to share his expertise on the matter and show everyone its not that scary to dig into your motor and fix that pesky rocker box gasket leak on your own.

00:01 – Intro.
00:35 – Remove the Gas Tank.
01:31 – Talk about the different tools you can use.
02:14 – Remove the 4 top bolts and the rocker box lid.
03:40 – Remove two rubber gaskets, the one sealing the lid and the square gasket in the middle.
03:59 – Remove the middle ring of the rocker box, carefully use a dead blow do not pry.
04:10 – Remove breather umbrella from the middle ring.
04:22 – The bolts inside the rocker box. 4 fasteners that take a 1/2″ socket. 3 fasteners that take a 7/16″ socket. 2 easterners that takes a 3/16″ socket head.
04:41 – Remove the last rubber gasket.
04:57 – Going over the next steps in the process, spark plug removal, jack bike up, put in gear, and make sure both rocker arms are down.
05:37 – Remove both spark plugs.
06:13 – Jack the bike up so the rear tire is off the ground and put the bike into second gear.
06:38 – Rotate the tire forward from the right side of the bike so you can watch the rocker arms go up and down.
07:03 – What it looks like when both rockers are down and even, you are now ready to remove the fasteners.
07:18 – Remove the fasteners on the rocker box, start with the smaller ones first, then the large ones.
10:40 – Remove the rocker box.
10:56 – Roasted, toasted and burnt to a crisp. That gasket is junk and was the problem!
11:33 – Scrape off the remaining junky gasket material with a razor blade and thoroughly clean the rocker box off.
14:17 – Make sure your rocker shafts are correctly aligned with the notch on the shaft and the hole for the long bolt to go in.
16:18 – A little push rod knowledge.
16:55 – James Gaskets!
17:36 – OOOOO AHHH! The new gasket is far more superior then that old stock gasket!
17:59 – Place gasket on the motor and align the holes.
18:20 – Introduce your rocker box back onto the engine, make sure the holes on the gasket below are still aligned.
19:15 – Get all of your fasteners started to ensure the gasket is aligned evenly.
20:05 – Snug down all of the fasteners evenly, but don’t fully tighten. Start with the small ones first.
23:02 – torque specs.
23:50 – Bust out that Torque wrench!
26:09 – Install the first rubber gasket and center square rubber gasket.
26:41 – Make sure the center ring is clean of any gasket material.
27:19 – Umbrella valves info and install on center ring.
27:48 – Install center ring onto the engine.
27:54 – Install second rubber gasket onto rocker box, make sure it is in the grooves.
28:17 – Replace the paper gaskets on the 4 rocker box lid screws.
29:27 – Install the rocker box lid, make sure the center ring and lid align with the engine.
31:24 – Bust out the torque wrench again!
32:15 – Rocker box leak fixed!
32:22 – Put bike back in neutral and lower bike back down.
32:34 – Spark plugs back in and get your gas tank back on!
33:01 – Fire it up and go for a ride! Ride it like you stole it!

Music by:

“The Dweller on The Threshold”
Composed by: Nihilore

“Out Da City”
Composed by: Fles Lit


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Comment (22)

  1. Can you tell me why my 2006 Honda VTX 1300 has never leaked a day in its life. And the high priced harleys always leak??? Even with 2k miles on them??? This is an honest question. I'm seriously looking to get a street bob but scared of having to go through all this shit. I do see it as a way to experience serious wrenching on my bike. But my question is why? My VTX is for sale currently but I am having second thoughts.

  2. Let lifters bleed down 30 minutes before removing or installing 4 big bolts on rockers! Removing last! Installing them first! I would also install rocker lockers to stop shaft noise when doing this job. Also use blue stuff on all bolt. Great video 👍👍

  3. i just changed out my rocker cover gaskets i got from Harley on my 1997 FXLR and they still leaked??? got thicker JAMES GASKETS.. and torqued them down 34 pounds and no leaking so happy… your video was a great video and really helped me… Thx …

  4. Excellent video and instruction. I'm about to do this job on my 2013 XL1200C and I could have done it using just my shop manual but this video is very helpful. Got a fancy digital torque wrench that my family bought me for christmas one year and it does both inch and foot lbs! (my torque elbow is out of calibration)

  5. I need to change the gasket that is in the bottom, do I need to remove all the gaskets and replace them aswell when i OPEN it even tho I need to replace the bottom one? t hanks in advance

  6. Excellent video bro! On my 01 883 Sportster i had a hell of a time getting the rear cover off, SHITTY welds! It seems as if I machine down the four rocker bolts and take the crowns off it should go back in no problem though! Thanks for the great video!


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