Head Gasket - How thin is too thin

MURDER YAMAHA

MURDER YAMAHA

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Minot ND
Getting ready to re-assemble my 600 twin, I was running the thinner head gasket on 91 octane.
Its a Cometic gasket and measures .25mm. It comes in the kit C4021.
Anyway, I have since made the decision to use 91 octane plus at least 20 Oz. of Torco everytime I fill gas.
What do you recommend ? Keep in mind, I maybe burn 3 to 4 tanks of gas all winter, and will always be carrying a couple cans of Torco with me.
Its currently ported, and will soon be adding twin pipes.
My compression was at 128 PSI with the .25mm Cometic.
 

Thank you ! and I know that, But that's not the point for this build. ;)!

I make 128PSI with a .25 head gasket
Anyone know what thickness it would take to get to around 145PSI ?
Fuel quality is not a concern.
 
MURDER YAMAHA said:
Thank you ! and I know that, But that's not the point for this build. ;)!

I make 128PSI with a .25 head gasket
Anyone know what thickness it would take to get to around 145PSI ?
Fuel quality is not a concern.
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FWIW on my 700 redhead removing the middle layer in my headgaskets brought the thickness from 0.7mm to 0.46mm
Compression pressure went from 120 -122- 121 psi, to 127- 130- 128 psi.
 
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SXR 700 tripple said:
2001 SXR with one layer removed. I have 150 psi across all 3 cylinders. 120's seems low.
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And still it impressed my budy who rides a low mileage 2012 Ski doo Renegade 800 E-teck . When he drove my old Venture his exact words were " Holly crap! This thing is more responsive the my Renegade!" :)
 
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A couple of bucks said:
Time for rings if your only at 128 w/ a .25mm head gasket.
Mine is a be-otch to pull over w/ the .6mm h/g.
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Mind you, the 128 was after the motor busted off a skirt becuse cylinders had been honed too may times, had lots of blow by ....
Cylinders are now at US Chrome being replated.
 
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Just wondering what is the stock compression on a 2000 venture 700 (redhead) also thinking of doing the head gasket mod sled is running at 125psi on all three!
 
rickk said:
Just wondering what is the stock compression on a 2000 venture 700 (redhead) also thinking of doing the head gasket mod sled is running at 125psi on all three!
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That's about right. Ironically I also have a 2000 venture 700.......I gain about 5 psi across all three after removing the middle layer of my headgaskets.
 
rickk said:
5psi gain did you notice much power difference?
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With all honestly, I did thin head gasket, Reed stopper notch mod, Apex helix, removed battery, starter and ring gear, rebuilt both my clutchs, also added home made transfer rods....basically all at once.
 
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Vincent said:
With all honestly, I did thin head gasket, Reed stopper notch mod, Apex helix, removed battery, starter and ring gear, rebuilt both my clutchs, also added home made transfer rods....basically all at once.
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when you installed the apex helix did you adjust the secondary any different than the stock setting?
 
The stock 70 twist works great . I'm currently running 80 for the little extra hard hitting acceleration
 
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