View Full Version : Lower rocker arm cover gasket leak

08-10-2004, 10:18 PM
I posted this in the old forum, just want to get this exposed. I like to decide to order the gaskets and replace them myself in the next few days, or may be not.

I am new to motorcycle, I have been following the forum for the last few months, and learning a lot from this forum.

My 98' Fat Boy has the same lower rocker box gasket leak from the front cylinder. I am thinking "do it yourself" James gasket kit from JP, and I have couple questions.

The service manual says that I have to remove the push rod assembly before removing the lower rocker arm cover. Is this a required step? Do I need special tools to disassemble and reassmble the push rods?

Also in the service manual picture, it mentions about the "umbrella valve" on the middle rocker arm cover. I assume that I don't have to take the umbrella valve off, if this not true then do I need special tools to remove and reinstall the umbrella valve?

How to "rotate the engine so both valves are closed on the head being replaced." as describes in the service manual?

What do you guys think? Is this type of works can be performed by a person who has done oil change, and brake works on cars?

All comments are appreciated.


08-10-2004, 10:57 PM
follow the book , the job is pretty stight foreward and you should have no problems, i wolud recommend that you do both cilenders while you are at it also replace the unbrila seals , no special tools realy needed except grinding down a allen wrench for the roker boxes, you should be fine..

08-11-2004, 12:05 AM
I posted this in the old forum, just want to get this exposed.


Please do post here, we want to populate these forums much as possible

Wreckerman has you covered, the book is a great investment

08-11-2004, 12:26 AM
Please do post here, we want to populate these forums much as possible

Agreed. I'm trying not to most much on the old site, considering it will only be an archive soon.

08-14-2004, 04:47 AM
I decided to try the "do it yourself" and ordered the James rocker arm gasket set. I have a couple more questions:

Should I re-torque the head bolts while I have the rocker arm cover off, there are currently no leaks at the cylinder base gaskets? If the answer is yes, will I need a special tool beside the torque wrench?

08-14-2004, 05:08 AM
I would leave the head bolts alone at this time , but if you have over 15,000 miles on this engine , you might want to think about deglazing the jugs and trowing in a set of rings with the base gaskets if you are under that milage then leave the jugs alone

08-14-2004, 05:39 AM
Thanks again for the advise Wrekerman. I will leave the head bolts alone, since the bike has only 11.5K miles.

08-15-2004, 02:57 PM
your welcome, and let me know if you need anything ealse, good luck

08-15-2004, 07:36 PM
Thanks for the offer Wrekerman. The rocker arm covers are off and cleaned for both cylinders awaiting the gaskets to arrive.

The from rocker cover removal was fairly straight forward once the gas tank mount braket is off.

The rear cover was a bit tricky due the very tight space. At one point I thought it will never come off, epecially the middle section. The trick is to unbolt the two bolts on top of the rocker arms first. Anyway, glad that I wa able to remove the rear rocker arm covers while the engine still mounted to the frame.

Now let's hope that they will back on easier. Can't wait fot the gasket set to arrive.

One question, should I use "red" locktie on all the bolts when I reassemble, I don't think any was used previously?

08-15-2004, 07:47 PM
If you take off the front motor mount, it drops the engine enough to give you more room to work on the rear jug..Somethin to think about before you start to put it back together, sorry I missed this earlier.. :(

08-16-2004, 12:23 AM
i dont think it calls for any locktite but red is a light one so a little would not hurt anything your choice

08-16-2004, 04:13 AM
Thanks for the suggestion 88FLHTC. I checked, and my 98's Fat Boy engine front mounts directly to the frame, no rubber mount. Not sure about the rear mount, but I think it is the same. Do you think your suggestion will work for 98' Fat Boy?

08-17-2004, 03:22 PM

I received the gaskets set and able to assemble the lower and middle rocker arm covers for the REAR cylinder (with the rocker arms inplaced and bolts loosely secured). However the top cover has no room to go in.

The top rocker cover will go in fine if I don't have the rcoker arm installed, but then it is impossible to install the rocker arms after that.

Any other suggestion, advice or detailed installation instructions?

How do I low the Fat Boy engine to get some room?

Please call me (719-593-8472) if you have done the rocker arm gaskets replacement before on f Fat Boy.

Thanks in advance. :(

08-17-2004, 06:23 PM
Somethin doesn't sound right here...you've got the bottom part bolted down to the head, then the spacer plate set on top of that, bt you don't have room to set the top part on?

I've had to set a few of the allen in the holes of the top piece before sliding it in ( no room to feed them in once it's in place) but I can't understand the troubles you're having.. :unsure:

08-17-2004, 08:52 PM
Thanks God I finally got the top cover in for the rear cyclinder. It really do need to tight all the bolts for the lower cover before the top cover can somehow slide in, from the right side (rear Brake side) of the bike.

For the record, the lower and the middle covers should be assembled first from the left side of the bike, some maneuver will require, once they are in, with the bolts loosely secure the lower cover, the rocker arms can now be installed, make sure that the push rods are at there lowest position. Once the push rods and the rocker arms are in placed, all the lower cover bolts can be fastened.

It is very tricky to replace rear cyclinder rocker gaskets, however it can be done without lower the engine.

Once you get the rear assembled, the front cyclinder will be a piece of cake.

Thanks for every replies, and supports.

08-17-2004, 09:05 PM
Glad to see you got it together !!!! drunks ^_^

08-18-2004, 12:35 AM
glad you got it figured out and that the job is done, it is a pain in the ass but nothing you can not handel

08-20-2004, 01:10 AM
So.. got it together OK ? back in traffic ?? No problems ?

08-20-2004, 02:12 AM
Thanks for asking 88FLHTC. There were couple minor leaks, but they are all fixed. No leaks or seepages at all now.

Problem number one was one of the push rod o-ring for the read cyclinder. I think when we were fiddling with the rocker arms cover, my son may have loosen the push rod tube assembly, and when he put the thing back together, the middle o-ring was in reverse with the washer. I slant cut an old o-ring and glued in the right position. This has stop the leak so far.

Problem number two was the new top rubber gasket for the rocker arm cover was a bit bigger than it should, it wasn't a perfect fit, we somehow pinched it and cut it in couple pieces when assembled the top rocker cover for the rear cyclinder. I partially lifted the gas tanks and was able to take off the top cover and replaced it with an old gasket, which is a better fit.

Again no more leaks or seepages anywhere now.

We are now confident that we can perform the task again if needed, it was a good experience.

08-20-2004, 10:06 PM
just a little tip , when you are haveing problems with those rubber gaskets not fitting right if you put them in the frezzer for a short time it will sreng them a little and make it easyer to assemble also you can put some greace were you want the gasket to stay and it will help hold the gasket in place

08-20-2004, 10:41 PM
Never thought of the freezer trick, that is a good one.

Grease on a gasket? That is scary. Would it cause premature leaks? I thought we should try to keep the gasket as clean as possible when installing it. Anyway, another trick learned.

Thanks Wrekerman.

08-20-2004, 10:57 PM
I used a little smear of Permetex2 to hold them in place..Just a tiny bit goes a long way, any extra just ends up on your shirt, the seat, grips.. :lol: :lol:

Great idea about the freezer !! drunks

08-21-2004, 01:17 AM
Come to think of it, I used the masking tape, and taped just over the edges, on two different places, of the lower rocker box gaskets to keep them inplace during the installation of the first few screws and bolts, and removed the tapes before secure all the screws and bolts.

07-21-2006, 04:32 AM
It has been about 2 years and 2,800 miles later. The 98' Fatboy this time leaks from the rear jug, the bike now at 14300 miles. I am almost certain it is the lower rocker box gasket. The James gasket has gave in. This could be during the installation we had to align the gasket too many times, or it could be that I didn't warm the engine enough before rides.

Time for another beloved hard labor in the very near future. I will go ahead and do the front rocker box also but not the head base gaskets (not sure I am up for the head and cyliner stuffs). I am thinking going with the HD metal gaskets. Does HD sell the gasket set for the rocker boxes like the James gasket set offered by JP Cycle? What is that part number and about how much am I expect to pay?

Sorry to say that I have a negative vote for James rocker box gaskets at this time.

Thanks in advance for the information.

07-21-2006, 01:17 PM
been useing james gaskets for many years , and they are the best ! in my opiun , maybe you have a little warpage or you just moved them around to much before toruging them down

07-21-2006, 01:40 PM
I'm with Wrecker on this I like the James gaskets as well. And if it where my bike I would only fix the rear rocker. My moto is is it ain't broke don't fix it. Those gaskets when properly seated will last a long, long time. Just my .02 cents

07-21-2006, 03:18 PM
Weckerman, you may be right about messing up during the installation. I remembered we had very hard time with the rear box. I was thinking it could also be that I didn't warm up enough before rides.

Old_Evo, I could have used that motto when I did the front box and left the rear alone, the rear wasn't leaked in the beginning. I was thinking it would be nice to have the same type of gaskets on both boxes.

Well, I may reconsider the James gaskets and may be only do the rear like Old_Evo suggested.

07-22-2006, 02:07 PM
to tell the truth , when i have to do gaskets because one or more fail , i always do the compleat top end set , has always saved me down the road i hate reworking anything

07-22-2006, 08:03 PM
Just went out and got the HD rocker gasket kit 17042-92A. The parts guy said I do not have to use after market gasket maker, gasket sealer or anything.

Should I just use the metal base gasket as it or should I apply automotive gasket sealer? If so, what brand/type of gasket seal should I use?


07-23-2006, 01:48 PM
put the gaskets on dry , that is how they are designed to work , if you put anything on them they might pull them selfs apart when the engine expands from heating up differnt metals expand differntly ok to use just a litle grease or semulear idem to hold a gasket in place while you assamble it but just a little

07-25-2006, 12:35 AM
Talked to a HD service man today, and was told that they use the copper pray gasket (spray can) on the HD metal gasket when installing.

Does anyone have pros or cons opinion?

07-25-2006, 10:35 PM
have used it in the past , it does work good , but should not have to use it inless there is slight warpage

08-08-2006, 05:03 PM
Found out that it was the middle rubber gasket got pinched and cut in half when it was installed. Couldn't see the leak until the gas tanks were removed. Anyway put in the old gasket and thing looks good so far.

So the James’s rocker box base gasket may still hold up, will continue monitoring.

Thanks for all the suggestions.