squish ?????


GS30,you are right megapower does not state sizes on web page,it was the "peak" brand heads by mountain performance where i had seen 22cc inserts.From rewiews here in past threads the "megapower" have seem to have a better results than "peak" heads,most people seem to happy with the performance and cooling of them.
Once again thanks to who have replied,now would i be better using a set of srx heads or buy megapower for hard trail riding remember 60% of the time low snow condition.
 
mega power domes

back in the days when I used to have regular contact with Mark G. from Megapower, I was thinkin he had more then 2 domes back then, maybe he only sold 2 of dome sizes to Maxx Perf who bought his head set up from him. Ya might try checkin around and see, I thought I remember something like mega 1,2,3,4 and 5 domes. Those are yamaha watercraft heads by the way.
 
This is what it was back when Megapower was still in business.

MEGA 2 : Big Bore Race
MEGA 3 : 700 race or high altitude
MEGA 4 : Big bore low compression
MEGA 5 : good pump fuel replacement
MEGA 3V : Viper high altitude
MEGA 5V : Viper good pump fuel replacement
 
Good luck finding anything other than 23.7 or 19cc domes. I put various emails out and talked with Mark G. in person and he said to talk with Gary at maxx perf. Gary said he only has the 2 I listed and will make no more. Mark did get me in the right direction and saved me money with other options, but he is completely out of the business now. Megapower heads are good heads but not vary user friendly if your looking for more out of them.
 
checked my notes, stock viper head, one gasket, .062, .050, .050.
24cc, 21cc, 21cc.
135, 150, 150
also the viper head and the stock srx heads both measure 11deg squish band angle.
does anyone have a newer style srx head to measure the angle? also could you measure the megapower too?
 
mrviper700, yep I was looking to bump up the compression on the PTO. After I posted, I realized that to do that on a Viper head, would require milling the deck surface and reworking the squish and domes on the center and mag clyinder's. Looks like it would be much easier to go with SRX or aftermarket heads.
 
srx heads

how much maching is required or is it direct bolt and go?
 
has anyone tried interchanging the billet domes from different head manufacturers? I wouldn't be to surprised if there was some interchange
 
The peak heads have the bolt holes in the chamber inserts where the mega heads look like the bolt holes are entirely contained in the head
 
ahh shit youre right, wonder if you could slap a peak head under a megapower tho? have some extra coolant clearance.

that's getting pretty redneck tho.
 
Looks like the megapower head is also taller overall, the sparkplug boos for the chamber insert stick up higher. You'd really have to redneck it to makem work.
 
Yamablue said:
Looks like the megapower head is also taller overall, the sparkplug boos for the chamber insert stick up higher. You'd really have to redneck it to makem work.
Click to expand...

ya, not worth screwing with, easier to just machine the megapower domes to whatever specs you need than it is to make the peak ones work
 
OK. I just measured my viper base gasket, and I think it is coming out to about 0.009" How about I double up on my viper base gasket, or use a stock SRX base gasket. From the picture, they looke the same. Does any body know how thick the stock SRX base gasket is? Doing this should raise my squish up to around 0.052"
 
I think the cooling ports are different on the SRX, as far as thickness I think 0.01 is pretty close, they're not a thick on, you can get 0.02 ones from maxx perf tho.
 
if you are just trying to raise your head to lower compression , why not just add viper gaskets as needed.
i run from one to four with no leak problems.
if you add base gaskets you will loose compression from closing port later as well as raising the size of combustion chamber. i think for what you want to do you just need to add one layer of viper gasket. they are around .011
 
do something up top, not below

Scott is correct here, just add a layer of headgasket ( that is if your using a mono head design), if you use a extra base gasket it will do the following, it will reduce the compression alot more, because it adds to your overall deck clearance, now just instead of raising the head area, your adding the entire piston top and deck height to the equation(more volume). Plus, your going to advance your port timing by raising this up, this is what is referred to as the "poor man port job", with a viper I wouldnt do it as they are already respectable, and if you have trail ported cylinders, its going to be even more of a change, meaning if your exh. port is already raised from porting them and your raise it more by adding base gaskets, your going to lose even more compression and raise the powerband of the engine to a higher rpm. As for the base gaskets, the srx has the better cooling holes then the viper base gasket, the stock yamaha gaskets range from about .010"-.011", thick, if you have seperate cooling heads on this sled by all means run the srx base gasket, it will help with the cooling.
 
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