View Full Version : Rocker box oil leak

15th November 2004, 05:13
I am a fairly new Harley owner. Been riding Hondas all my life. My 2002 Hugger (3760 original miles!!) just started leaking oil though rocker box gasket. What up with that? Am I supposed to be happy with that since I now own a Harley? Hell my junky Honda has 25K miles on it and it doesn't leak a drop!
Well hell, I just want some feedback from you guys and I will replace the gasket myself. My next question is do I have to rip the whole engine off the frame or can I replaced all those top gaskets with the engine in place?

15th November 2004, 06:51
Take the tank off, and you can pull the jugs off the bike. You might even be able to change those gaskets with the tank on.


15th November 2004, 07:09
Buck, I believe every 2002 owner to include me had the rocker box leak problem.

Changing the gasket is not difficult at all and can be done with the tank on but is much eaiser with it off. Be sure and buy some good gaskets (James are recommended) and what ever you do do not put HD gaskets or you will just be changin them again in 10,000 miles or less.

If you decide to remove the tank there is no need to drain it like the manual says. Just turn your petcock to off and nothing will come out.

No need to tear apart your whole engine but be sure and buy or have a service manual handy.

15th November 2004, 14:03
I just replaced the rear rocker box gaskets on my 1200 sport yesterday. Have done nearly 20,000 miles and this is the first time I had to do the job myself (had the front one done under warranty after about 4,000 miles).
Personally, I didn't think this was easy. Main problem was the limited space between the backbone of the frame and the rocker boxes themselves. I had to cut down one of my hex key so that I could squeeze it between the two. Spent about 10 mins turning a bolt 1/8 of a turn at a time. Had to remove the choke mounting thing to move the rocker box cover forward a bit before sliding it out sidways. Also had to remove the tank, seat, battery, air cleaner and pushrods. Didn't put the pushrods back in properly (they didn't seat properly) so the engine sounded terrible when I started it up. I had to pull it apart again. Only took 2hrs second time took 6hrs first time (inc removing the old gasket sealant). Ride to work was fine this morning. I don't want to put you off doing it yourself, just don't think it's as easy as working on a car!

Happy rididng.

15th November 2004, 14:35
The trick is to take out the dremel tool and cut down the allenwrench. Anyone who does this a lot will already have one cut. I have ratcheting wrenches and my bit was cut to fit that bugger. I have a question. I read James gasket recomendation and want to know if they are better than the new H.D. metal gasket. I recently changed mine to metal eventhough I later found the leak to be coming out of a crack in my rocker cover(crack near front mount hole). I never had a leak before and hope the new gasket in not going to start. A bunch of you newer bike owners have been complaining about leaks and I never had them before. Thanks :D

15th November 2004, 15:40
Even easier buy a rocker cover wrench(cheap) saves cutting up an allen wrench and makes the job a hell of a lot easier

15th November 2004, 22:04
I just did my front cylinder last night. My leak was from between the bottom cover and the cylinder head. When you take the bottom cover off, you first have to make sure the lifters of both valves are on the base circle of the cam (valves closed) and pull the rocker arms. When you're putting ht bottom cover back on, put the rockers in place on the cover first before putting the cover on the head. It is all outlined in the shop manual, so make sure you have one. If the leak is in the top covers, that isn't a big issue.

16th November 2004, 19:03
Up until mid 2002, all engines came with paper lower rocker cover gaskets. In 2002, HD went to metal ones and it solved the leak problem. I'd recommend replacing both of them while you have it apart. The others have given many tips that will help a ton. It really is a simple task, provided you have the factory service manual. The new metal lower gaskets from HD are fine. And they are not that expensive. Plus you are going to get to bond with your new ride. Enjoy.

17th November 2004, 22:25

It's easy to do the rocker box gaskets. Spend $20 for the Motion Pro tool for the allen bolts. Well worth the $$, IMHO. My 2001 has 35,000 miles and no more rocker box leaks after the initial change to metal gaskets.

AFAIK, the only thing on the Sportster that requires engine removal is a bottom end repair (you can pull the tranny without removing the motor). Keep the tach below 7,000 RPM and your bottom end should last a long time.

What kind of Honda do you have? Just curious.

17th November 2004, 22:55
I just spoke to a tech at my local HD dealer, who is into buells & sporties (he says' sporties are "the shit"). He said that you don't have to take the rockers out first. You can just pull the lower cover as one unit. The shop manual says to do it because the procedure outlined is fore a complete teardown. But it ain't no big deal to pull them anyhow. It looks more intimidating in the pictures that it is to really do it.

18th November 2004, 14:10
Jireh sells the Motion Pro tool for $12.95...really a nice deal. I was looking at the left rear rocker cover bolt and it appears that at least on the rubber sporties it can be easily accessed with an extension and 3/16 hex socket directly from above with the gas tank removed. I will confirm this later. I usually take the tanks off when I am doing anything in that area on a bike...my sporty's tank comes off real easy, to boot.


18th November 2004, 14:17
Keep the tach below 7,000 RPM and your bottom end should last a long time.

Having just had my first fiber optic sigmoidoscopy ("Man's arsehole attacked by long snake puffing air and taking pictures...":eek: ) yesterday...this has an entirely new meaning to me. Thanks for the tip! :D


19th November 2004, 00:29
I have a 1979 Honda CM400T with over 25K miles! I just painted it a few weeks ago in my garage. I have never cracked the engine open. It has the original clutch too. The only things changed on this old warhorse have been the chain and sprockets (once), both tires (twice) batteries (three times) seat cover (once) and I had a small crack in my rear fender welded. Other than that, its very reliable. My oldest now drives it to school. I am just a little disappointed with my Sporty and the leak and all...

19th November 2004, 16:38
Bert. Thanks for the info. I know you know what the hell you are talking about..I will get the James metal gaskets and take care of it myself. I do have the shop manual and this will make a good weekend bonding session with my 16 yr old son.
What do you think about this leak business? I am a proud American and have always been proud of buying American made whenever possible. I am a longtime Honda owner and I was a bit disapppointed to see this leak on my fine American made motorcycle. Am I expecting too much from Harley-Davidson being that my junky but reliable 1979 Honda CM400T(with over 25000 miles) does NOT leak a drop?

19th November 2004, 16:49
I had to change my gaskets with a little over 7k miles on it. I think HD just used crappy gaskets. I have not had another problem with it since.

22nd November 2004, 20:27

I think I have a similar leak in the rear rocker box gasket. My '00 sporty only has 250 miles on it. I was at the dealer yesterday and inquired about having HD "Good Will" the repair. The guy working there said it was not likely but not impossible. Obviously the bike is out of warranty but c'mon! Anyone else have any experience with this. Apparently it is not an uncommon problem.


22nd November 2004, 22:01
Yea SoCal,
I have been doing the research on this subject and have learned that it's not "will you ever get a leak" BUT "when will you get a leak" on virtually all Sportsters. The answer is replacing the factory paper gaskets with new metal ones. I contacted James gaskets in Nevada and there are ton of retailers (mostly bike shops) in SoCal who can order a set for you. The repair is relatively easy if you know how to turn a wrench. The local HD dealer wants $400 to do the job. I'll do it myself. If you surf and google you will find several Sportster websites that talk about the problem, tell how to fix it and even show digital photos of the process.
Also, I get the feeling that as a Harley owner you should not complain about it. It's part of owning a Harley and surely not enough to commit treason by selling it and buying a rice grinder.........

23rd November 2004, 18:25
Hey Buck8200,

from all the research I've done even prior to purchasing the sporty I knew this would eventually be a problem but you gotta admit that after 250 mi that kind of gasket failure is ridiculous. It is just another example of cost-cutting that unfortunately ends up with us being stuck with a crappy product. Don't worry, I'm not selling the sporty because of a minor problem like this but I do feel justified in complaining. With the cost of these bikes when compared to some of the other products on the market I really don't agree that oil leaks are part of being a Harley owner. Maybe in the AMF days. :-) I'm not trying to be a jerk or anything. Just my thoughts on the matter.


23rd November 2004, 18:26
...Oh and by the way, thanks for the info on the replacement parts.