Aftermarket EVO base gaskets. Problem solved?
Dirt don't hurt
Joined: Jan 2011
Posts: 21,062
Likes: 4,547
From: Haslet Texas
Does Harley make steel base gaskets now?
Club Member
Joined: Mar 2009
Posts: 66,094
Likes: 51,353
From: Niles Canyon Ca.
Been a while since I bought any dealer evo stuff but I did get a set of the MLS base gaskets from them. Older bikes I try to stay with Cometic, James are fairly local and I had an inside with them for a while and their stuff just isn't what it used to be, they still use a lot of the non metal silicon stuff.
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Joined: Aug 2016
Posts: 54
Likes: 4
From: Colorado Springs
As another said - properly warming up the bike before having the powertrain put out significant power will prevent the twist that will cause the base gaskets to weep. I put gasket conditioner (some kind of grey nonhardening rtv) on them liberally, and true to their word they haven't leaked or caused issues as of yet, despite me not warming it up quite to where it should be.
Again James or Cometic is the best way to go.
Again James or Cometic is the best way to go.
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Seasoned HDF Member
Joined: Jul 2014
Posts: 8,564
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From: Cental, MI
Never heard of "twist" but it is true that once thoroughly warmed up the Aluminum Heads and Cylinders have grown substantially... squeezing the Sandwich together between the Case and the Studs... resulting in the most effective "seal" Until warmed up, the seal is loose at best [relatively] and putting pressure onto the gaskets at this point, is bound to create a leaking situation..You can tell alot about the Rider by looking at the base gaskets...
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Dirt don't hurt
Joined: Jan 2011
Posts: 21,062
Likes: 4,547
From: Haslet Texas
Never heard of "twist" but it is true that once thoroughly warmed up the Aluminum Heads and Cylinders have grown substantially... squeezing the Sandwich together between the Case and the Studs... resulting in the most effective "seal" Until warmed up, the seal is loose at best [relatively] and putting pressure onto the gaskets at this point, is bound to create a leaking situation..You can tell alot about the Rider by looking at the base gaskets...
A friend of mine had his motor top end done at a local indy and the base gaskets seeped from day one after the rebuild.
A couple of years later he brought his bike over to my house and we did another top end due to a blown head gasket.
I used Cometic steel gaskets and they sealed up that motor very well.
Grand HDF Member
Joined: Apr 2007
Posts: 3,711
Likes: 3,028
From: Brighton, MI
Multi layer steel gaskets are a good fix, they have a "bead" stamped into the metal that applies constant pressure to the sealing surfaces. You want that constant pressure when the cylinders have "shrunk" in length when cold, and that bead will also compress when the cylinder has grown in length (hot). Also consider having the base of each cylinder machined flat (trued). This is the best you can do. YD