REPRINT FROM OLD HTT: EVO BASE GASKETS

[ClassicRider2002]

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DISCLAIMER: THIS IS A REPRINT TOPIC FROM "OLD" HTT

I have saved many great topical discussions as "links" over the years and would hate to see these lost, so I am reprinting this TOPIC here, which may "perhaps" help some.

TOPIC:  EVO BASE GASKETS  05-16-01


From: marty  (Original Message) Sent: 5/16/2001 10:36 AM   Message 1 of 1 in Discussion
Ever notice that when they start leaking AGAIN that it's in the same place?
Just for the hell of it I put mine on a layth, and guess what.The bottom of the jugs
WERE NOT FLAT! Base gaskets compress to 5thou.( acording to the big guys)
The left rear corner of my rear jug was 7thou.different than the 3 other corners.
the front jug was concave on the left side between the front and rear corner by
5thou. I just had to share this.I really hope that this helps everyone with this
problem.If mine were like this,I'm sure that I'm not the only one. rine safe!

[ClassicRider2002]

   

From: AlphaSamuel Sent: 5/16/2001 11:14 AM   Message 2 of 1 in Discussion
That's what happens when you have castings made overseas by unskilled workers, then ground down by robots.  The Factory has tried just about everything from different gaskets, to 0 rings and still they leak.  I know people who have invested in expensive tools to "square" off the bases as you have done and the damned things still leaked.  I finally gave up in disgust, went back to the basics of assembly of aircooled engines with aluminum jugs w/steel liners, started using avaition gasket cement on all my gaskets and, viola!  No more leaks.  Sure a little squeezes out, but my trusted finger tip and a rag and mineral spirits clean it right off.  It also can be used on bolts where installed into aluminum housings to prevent annealing of dsisemiliar metals.   They will never sieze, nor gall your aluminum threads.  Worked for me.  Samuel   

[ClassicRider2002]

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Anything added beyond this point is new information.

Regards,

"Classic"


I FOUND THIS POST IN ANOTHER THREAD AND I FEEL IT'S WORTH MENTIONING HERE:

From: Harleyguy5731 Sent: 3/20/2008 2:41 PM
Evo's have base gaskets, Twin Cam's have "O" rings.  The reason that base gaskets leak on EVO's is that the heads were either not torqued down properly when they were installed either that or the rider does not warm the engine up sufficiently before getting into the throttle.  The aluminum heads grow as they get hot and as they grow the seal the thin base gaskets.  If the heads were torqued down beyound spec's as the jugs expanded they would tear out the bolts.  When a rider gets into the throttle before the jugs have expanded sufficiently, the head gasket will get trashed from pressure being built up in the cylinder, Twin cams tend to require less warming up that the EVO's, however they also do require some warming up to allow the jugs to grow and to seal the "O" rings,  I hope this helps!  Harleyguy5731

[Flat Dog]

Permatex flowable windshield sealant will sometimes stop a smaller base gasket leak. It's worked for me in the past when I was too lazy to tear the top end down, lap jug bases, put new gaskets in, new head bolts, gaskets, bla bla bla...