duck57
New member
alright you guys, i heard for quite a while about taking the center section of the head gasket out to up compression. whats the skinny on this? do you use old head gasket or do you alter a new one. how much does it up compression. do you need to rejet. if so how much. what octane is needed afterward.another topic has anybody had trail porting done on a viper, does it help much?not looking for fastest sled on the block just want to stay with other 700s
xsivhp
Active member
I think the head gasket mod only works on the non power valve 700 motor.
redsnake3
New member
i got the head gasket mod done and it boosted the comp. by about 5-7 psi and still gainin since the rings are new and still settling in the cylinders. you shouldnt need to rejet. as long as you run premium gas it should be fine just check your squish rate first. i have the porting done as well and you can really feel the difference, they say its good for 12 h.p.
yamvip
New member
Really???And what the head gasket mod consist of??
Millinocket Rocket
New member
12 HP???? WOW- where's MrViper-- we need to get this confirmed! that must be with the porting too? wonder how much just the head mod gives ya
yamvip
New member
Thats what I'm thinking,wonder if it just all hype though.If not mine is get done!!!
nodoo_s
New member
i also removed middle layer and when you try and start one with the mod and one without deffinate increase in compression. i've been running mine for 3 years now no probs
redsnake3
New member
sorry guys no need for mrviper... i meant 12 h.p. for the porting. im not sure how much for the headmod.
yamvip
New member
still 12hp for a port job thants great,you gotta be happy with that,was it dyno'ed??
nodoo_s
New member
you might get 4hp from the gasket mod
redsnake3
New member
no dynos around but thats what was claimed.
Millinocket Rocket
New member
nodoo_s said:you might get 4hp from the gasket mod
nodoos-- 4 horse is pretty good- do you need to change jetting or anything else, or just run premium fuel? i was also under the impression that this mod only worked for non-PV motors.
yamaholic22
Active member
increasing the compression works on any and every motor if you have high enough octane fuel to resist detonation. The vipers already have fairly high compression though (on two cylinders) so it is a lot more risky to do it on the vipers as opposed to the nonvalved triples.
Millinocket Rocket
New member
thanks holic--just wondering how risky. a stock viper calls for 88 oct. or better, if you ran 92 premium with the gasket mod you'd be safe wouldn't you? what else would you have to worry about-- bad gas, air temp. differences, etc.
yamaholic22
Active member
In my honest opinion i think that it is too risky at sea level. I dont trust fuel quality good enough to be worry free on a -10 degree morning on a railroad grade with that much timing. I dont think the juice is worth the squeeze on this mod. 99 out of 100 times you will probably be fine, but that one time you wont will cost you, and take the fun out of the weekend.
nodoo_s
New member
i'm even jetted down one size and have run this mod from -30 to 55 and never had an issue from sealevel to around 3800' for the last 4000 miles. I've rode in canada many times where gas is questionable and run regular gas once or twice. one layer is fine, 2 layers like the sx's is a little more risky.
bolin22
New member
i run a 02 viper with head gasket mod......i love it.......always run 92+ and NEVER run without yamaha octane boost.(just in case of bad gas).......
I have heard good things on a Viper Gasket mod with no other mods to the motor...Free power...
nodoo_s
New member
My dealer claims 4-6 with one layer removed, so i just say around 4. there is deffinately snappier throttle repsonse on the low and mid.
MountainMax
New member
I removed two layers on the head gasket on my non powered valve MMax before finally buying a Peak head, never had a problem and i was running regular gas (all i can get here) and I was running triple pipes and other mods.......