HarleyTechTalk

Hey guys, I've just put my 2019 Slim on the dyno after the build. It now has a few cylinder base gasket oil leaks...  The gaskets I used were Cometic head and base gaskets.

I've read this is not all that uncommon? I used S&S head bolts and Cometic head and base gaskets.

Does it take time for the gasket to fully seal? Or am I going to have to tear it down and replace base gaskets?
Thanks.

Is it weeping or dripping? My last new bike (2015 RG) weeped slightly at the base gaskets for about 100 miles or so, then it stopped. Like the gaskets sealed up.

Quote from: lilchief on July 24, 2023, 06:49:43 PMIs it weeping or dripping? My last new bike (2015 RG) weeped slightly at the base gaskets for about 100 miles or so, then it stopped. Like the gaskets sealed up.

Yes thanks. After a thorough degrease and another long ride it seems to be much better..... I guess it's going to seal up eventually.

I  put a small amount of sealer on the crankcase join just incase .

Quote from: To The Max on July 25, 2023, 03:59:54 PMI  put a small amount of sealer on the crankcase join just incase .

Thanks Max, what sealer do you use?

I presume the motor was heat cycled before being run on the dyno?

Did you follow the S&S procedures when torquing the head bolts?

I have found that when torquing the heads down the torque doesn't distribute perfectly evenly across all 4 bolts and a second pass is needed to distribute things as intended. For example, if the tightening step is say 20lbs, I'll torque the bolts down in sequence then go back and redo it. I essentially perform each tightening step twice.

If the leak remains I'd do the above when reinstalling. Fingers crossed the leak seals up for ya. Been there before with head gaskets that seeped, it's annoying.

Couple things I didn't think about earlier...

Did you use the same cylinders as before? If not, were the decks straight on the new cylinders? I've found some waves in spots on new S&S cylinders but they didn't translate to a leak. Base gaskets installed right side up?

If everything was done properly I'm thinking maybe too much heat in the motor too quickly which didn't enable the gaskets to seal perfectly or what I mentioned in my last post. I've never had a small seep stop completely but got my fingers crossed for ya.

Quote from: Adam76 on July 25, 2023, 07:26:36 PM

Quote from: To The Max on July 25, 2023, 03:59:54 PMI  put a small amount of sealer on the crankcase join just incase .

Thanks Max, what sealer do you use?

locktight 574

I always use a light coat of copper-coat sealer on base gaskets (Vht brand)

Three bond here . Torqued to cometic specs ?