headgasket mod on a viper

[Jeff22]

I know this has been probably covered to death, but I did a search and didn't really come up with any good answers. I know you can do the headgasket mod to the Viper and was wondering if anyone out there has done it themselfs and exactly what to do (how many layers to take out of each cyl. etc) and if they found the results to be good or any other points. I know some people think it's risky in a Viper but with quality fuel some people say it's not a problem. I know there are a few out there who been runnin them with it done hassle free. thanks muchly for any responses,,,, Jeff

 

[Millinocket Rocket]

there's one long gasket that covers all three cylinders, and is three layers thick. i believe you peel the middle layer out, and put the other two layers back in. try talking to "nodoos"-- he's done this mod to his viper with good results.

 

[redsnake3]

you need to check ur squish rate, which means the distance between ur piston and head at the edge of the cylinder as far over as you can. i had enough room to take out two layers might not be good for you. check with mrvipers post about squish rate got some really valuable info.

heres the link
http://www.totallyamaha.net/forums/showthread.php?t=12081

 

[Jeff22]

thanks alot guys, I'll check that out now and read up on squish.... if I only take one layer out does anyone know for sure if it should be the middle layer or if it matters.?? thanks

 

[redsnake3]

yeah take out the middle gasket it is metal. and metal on metal aint good.

 

[Mtnviper]

The center layer is .005"-.006" thick. The outer layer's are .010" thick each.
Pulling just the center layer will reduce the total combustion chamber volume by .475 CC's. Pulling both the center and one outer layer, will reduce total chamber volume by 1.42 CC's.
Chamber spec's for a stock Viper head are
PTO= 24.55-24.85 CC's
CNT, MAG= 21.35-21.65 CC's
As you can see, there is a production tolorence of .3 CC's.
Some where I had it calculated out what the compreesion ratio change is, but I cant find the paper I had it on. However if I remmember correctly, one layer made less then .25 compression ratio increase. While 2 layer's was around a .4 compresion ratio increase.
One layer at .475 CC's is just barely over Yamaha's production tolorence. One layer dosn't make a whole lot of difference in performance, but throttle response is improved, and every little bit helps!
With two layer's pulled you'll be able to feel the difference in mid-range power. However with two layer's removed, I strongly recommend you check the squish, (just in case your Viper, has a head on the tighter side of the specs) and use only good premium fuel.