I just bought a set of SRX heads that have been cut down 0.030" to use on my Viper. As the stock Viper head has different volumes for the cylinders, I am wondering if I need to jet the individual cylinders differently, or is it OK leave the jets the same for all 3 cylinders? Also, I am planning on reusing my stock head gasket as it looks to be in good shape. Do I need to remove the middle layer, or is it OK to use the whole thing.
I would mock it up and do a squish check and see where your at, it will also depend on what year the srx heads are,as the 98-99 heads are a little bigger volume then the 2000-02 are. the heads are identified by the casting, 8dn-00 are the 98-99, 8dn-10 are the 2000-02.
you will also need to make up a water rail to hook it all up.
as far as jetting, likely youll need to go up just a tad on the pto end because of the added heat from the primary, yamaha lowered the compression in this cylinder so you could use the same jets in all 3 cylinders, but youll have the same compression in all 3 now, will be just lke a srx jet set up,just a half-2.5 jet size differance is usally more then adequate.
you will also need to make up a water rail to hook it all up.
as far as jetting, likely youll need to go up just a tad on the pto end because of the added heat from the primary, yamaha lowered the compression in this cylinder so you could use the same jets in all 3 cylinders, but youll have the same compression in all 3 now, will be just lke a srx jet set up,just a half-2.5 jet size differance is usally more then adequate.
mrviper700 said:
Thanks for the reply!
The lower compression on the PTO side has always seemed odd to me. Doesn't a properly setup clutch just run warm to the touch? I would think if anything, the mag side would be the hot side due to the exhaust heat going over there.
I have the water rail, but I am wondering where to put the temperature sensor?
ALso, when you say to go up a half jet size, does that apply to the pilot and main or just the main or just the pilot? Will the fuel screw need to be adjusted too?
Not sure if it makes a difference, but I am running SLP pipes on this sled. It is currently jetted for -20F @ 0 - 3000 ft using SLP recommendations.
ya, I always thought it was goofy to to change the compression on one out of 3 cylinders too. I guess it was a big deal to some people to have all the same jet numbers in the carbs so they did that. Once I get a sled set up, I dont usually need to change jets in a trail sled for the conditions in which I ride. Much below zero and I am not gonna be out riding a snowmobile for sure....lol
just the main gets a tad bigger jet. On my own sleds with properly set up clutchs, I agree with you and my clutchs dont add any heat, sometimes they wont even warm up your hands when its cold out...lol. I dont stagger them but use all the same, but I was just telling you to set up the way yamaha keeps it.
I would just add a bung if needed to the water rail and screw in the temp sensor there, or they sell inline fittings for the sensors to go in the outlet hose, you have to cut the hose and place the fitting in between hose halfs.
With a stock viper head, the mag cylinder is for sure the hottest due to the design, and yes, your likely to have extra heat in there with your pipes, just jet it according to what the plugs and piston show you. You can start off with SLP jetting and work your way around from there.Theres nothing wrong with staggered jetting, its all in what applies to your specific set up needs.
just the main gets a tad bigger jet. On my own sleds with properly set up clutchs, I agree with you and my clutchs dont add any heat, sometimes they wont even warm up your hands when its cold out...lol. I dont stagger them but use all the same, but I was just telling you to set up the way yamaha keeps it.
I would just add a bung if needed to the water rail and screw in the temp sensor there, or they sell inline fittings for the sensors to go in the outlet hose, you have to cut the hose and place the fitting in between hose halfs.
With a stock viper head, the mag cylinder is for sure the hottest due to the design, and yes, your likely to have extra heat in there with your pipes, just jet it according to what the plugs and piston show you. You can start off with SLP jetting and work your way around from there.Theres nothing wrong with staggered jetting, its all in what applies to your specific set up needs.