Splitting the headgasket of a 1997 venture 500

norwegian

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If I take one layer out, how much hp gain could I expect? And where on the powerband? Will it be more responsive?
 

I only leave one in, either top or bottom. Have done it for years on 4 different sleds, with zero problems on 91 octane fuel.
 
The 500 already has a thinner gasket from factory than the 600 or 700 so the compression is higher already. If you do split run very good fuel all time or it will ping and cause issues.
 
The cases were changed on my 500. Seems it has 3 layers. How thick is the thin and the thick headgasket?
 
You can on the 600. We actually run the thinner gasket right from Yamaha. 500 is thin already.
 
Just food for thought .... pogo #s
Head gasket thickness by year
1994-1995 -- .6mm
1996 -- 1.4mm
1995-96 MM 600s -- .8mm

My 96 XT6 has the .6mm 94/5 h/g on it. Compression is at 139 & 141. It is a BEAR to pull over.
 
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I measured it, all layers are 1,1 mm, and the middle is 0,4mm of the total. Will this be safe? I don't mind if it's a little harder to pull over.
 
Not sure, looks like his was a 4 layer one, pretty sure mine has only 3 layers. I'll check tomorrow.
 
Just use 2 layers. That should put it somewhere in the neighborhood of < .8mm. Spray both sides of warmed h/g w/ copper coat to ensure that you won't have to take it back apart for a leak.
 
It's red and has a different gearing (18/38) and probably different primary set up as well.
 
The middle is 0,4 mm so it would be 0,7 mm plus whatever the sprays add on.
 
I seem to remember that 97 & up twin heads had less squish than the 94-96s. Those two layers plus copper coat should be perfect. I definitely wouldn't go thinner than the 2 layers you mentioned earlier.
 
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