1992 Fatboy, base gasket material
Grand HDF Member
Joined: Sep 2022
Posts: 4,375
Likes: 3,785
From: Florida
sorry, I think I phrased my question wrong. I’m not concerned one bit about it sitting. My concern was others were mentioning that cometic and James gaskets blow out easy. They were saying they prefer the true Harley Davidson gaskets now. I didn’t know any better and just used Cometic.
Last edited by Rains2much; Feb 3, 2026 at 10:30 AM.
Seasoned HDF Member
Joined: May 2008
Posts: 21,105
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From: South Carolina
The currently available gaskets from Harley Davidson are as good or better than aftermarket gaskets.
Last edited by Dan89FLSTC; Feb 3, 2026 at 10:28 AM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,076
Likes: 7,601
From: Poolville
Yes, many Harley gaskets and seals are the cats *** compared to aftermarket.. However I really don't think an MLS or SLS gasket is going to bow out.. Evo motors were notorious for cylinder bases not being true to the cases.. Therefore the necessity of the OEM thicker fiber gasket that ended up putting the piston further in the hole than necessary. It was a cheap way for the Moco not to true the cylinder base..
If everything is machined properly your not going to beat Cometic head or base gaskets..
If everything is machined properly your not going to beat Cometic head or base gaskets..
Grand HDF Member
Joined: Sep 2022
Posts: 4,375
Likes: 3,785
From: Florida
Yes, many Harley gaskets and seals are the cats *** compared to aftermarket.. However I really don't think an MLS or SLS gasket is going to bow out.. Evo motors were notorious for cylinder bases not being true to the cases.. Therefore the necessity of the OEM thicker fiber gasket that ended up putting the piston further in the hole than necessary. It was a cheap way for the Moco not to true the cylinder base..
If everything is machined properly your not going to beat Cometic head or base gaskets..
If everything is machined properly your not going to beat Cometic head or base gaskets..
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,868
Likes: 7,987
From: poway
The big problem with cometic is that the case has to be flat.. The big issue is where the cases meet. I've had them leak there. I typically put a dab of case sealer right at the case split line..
Thread Starter
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Intermediate
Joined: Aug 2013
Posts: 45
Likes: 23
From: Pacific NW
OP~ you should know that using a "razor" to remove gasket material is a "no-no." Always use a sharpened wooden chop stick or popsicle stick. These can't "dig" into your mating surfaces.
Next, I used a rubberized steel die-cut gasket and never have another leak again. We had similar mileage, so yes, they ARE durable.
Next, I used a rubberized steel die-cut gasket and never have another leak again. We had similar mileage, so yes, they ARE durable.
I've had good luck with the rubberized gaskets on many many bikes, but this one probably doesn't have flat mating surfaces anymore. So thats not the answer either.
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HDF Community Team
Joined: Dec 2005
Posts: 5,397
Likes: 2,599
From: NC USA
The way to remove them is simple. Use a clean piece of smooth wood (popsicle stick) and trowel on a thick coat of paint remover. Do not use a brush. Turn the lights off and the next day, a plastic razor blade will bring them off. Use the bottom half of torque plates, stick on a 6' round, 220 grit, tap a hole out of the center and use that for lapping, if you need to.
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Grand HDF Member
Joined: Sep 2022
Posts: 4,375
Likes: 3,785
From: Florida
I’ve had good luck with Permatex gasket remover spray. Tape off, spray generously, let soak 4-5 hours, remove gasket. If it still leaves another layer, get what you can off and then spray and soak it again.