srx head cutting

800vmax4 said:
When I built my 2002 SRX engine I removed the stock pistons,cylinders, + heads and set them aside untouched so I could always return the sled to stock
I initially used a set of 98 heads and cylinders that I cut + ported[before I installed the"Peak" head]
I cut .035" off the mating surface and .030" off the squish band of the 98' heads.
Results:
-installed squish: .058" [stock with my 2002 heads was .061" ]
-installed cyl head volume: 20.75cc[stock with my 2002 heads was 22cc ]
-new comp ratio: 12.2:1 [stock with my 2002 heads was 11.5:1]
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thanks 800vmax4!! those are the answers i like....the ones w/specs/results.

i'm assuming you used 3 base gaskets too?
 

mopar1rules said:
thanks 800vmax4!! those are the answers i like....the ones w/specs/results.

i'm assuming you used 3 base gaskets too?
Click to expand...
No...I just used one stock SRX base gasket. The cylinders are ported though ,basically close to stock viper specs.
 
I should have measured the winderosa gasket, it might be as thick as 2 or 3 yamaha gaskets. 118psi just don't please me. Now my riding buddy is going from a 583 & getting a '04 RX-1, I need my srx to be running good to keep him behind me. How are you guys checking squish??? I use a short piece of solder, works pretty good, just turn it over slow.
 
ottawaair said:
I should have measured the winderosa gasket, it might be as thick as 2 or 3 yamaha gaskets. 118psi just don't please me. Now my riding buddy is going from a 583 & getting a '04 RX-1, I need my srx to be running good to keep him behind me. How are you guys checking squish??? I use a short piece of solder, works pretty good, just turn it over slow.
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The RX1 should'nt be too much of a problem.
I'll try to explain how I measure the Squish clearance :
I check the squish with solder, [remember to have it long emough that it can't fall in the cylinders], make a 90 degree bend in the solder,eyeball the length you are inserting in the spark plug hole so its about the same as half the clylinder bore. Always parallel the piston pin with the solder, insert the solder in the spark plug hole til you feel it butt up against the cylinder wall then slowly rotate the engine by hand on the clutch until you feel it contact and "squish" the solder. Remove the solder and measure its thickness at the end with a micrometer or verneer calipers.
 
have u ever try to check it with a proper guage ??for squish clearance ...you will have to pick the good one cause u will not have the same result from solder to a real tools ......not sure raising the port with base gasket is a good idea .u change many things not only auxliary port height ...never did test on dyno but i'm sure its not better ...u play with timing doing that
 
modsrx said:
have u ever try to check it with a proper guage ??for squish clearance ...you will have to pick the good one cause u will not have the same result from solder to a real tools ......not sure raising the port with base gasket is a good idea .u change many things not only auxliary port height ...never did test on dyno but i'm sure its not better ...u play with timing doing that
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I have not tried anything other then solder...have'nt seen a proper squish guage.
I agree the optimum way to improve performance is to machine the ports...I guess some engines do respond a bit to stacking the base gaskets, but I have not used that technique in recent years, so I don't know if an SRX would respond well to it.
 
mopar1rules said:
800vmax4, how did that '02 srx run for you, w/your machined '98 heads and ported '98 cylinders? how is the dcs light w/those mods?
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My 2002 SRX also has a 144 x 1 1/4" Ripsaw,reverse, and Viper shocks so its performance is relative.
The sled is quite strong, runs consistently above 100mph on GPS with a best of 106mph.[pretty fast for a 144"] I can consistently outrun the 900 fusions + 800R Renegade I ride with as well as beat them at the pumps.
I was having trouble with my DCS going off, so I wired in a switchable bypass and used it when racing my buddies or for long lake runs until I checked my plugs after a high speed part throttle run and they were pure white! The DCS was right! I am very lucky I did not melt down! I then removed my 2' timing advance key and fattened the needle jets to Q8's...now as long as I have good fuel, I don't get the DCS flashing. I also have been able to run smaller main jets since I fattened up the needle jets. Because of the compression ratio I am running the sled is very sensitive to low octane fuel...the group I ride with use me as "Fuel Tester" after we refuel on our longer rides...no DCS play hard...DCS flashing take it easy. I no longer use my DCS bypass switch!
 
I checked my squish, here are the #'s
pto -- .067"
center - - .064"
mag -- .066"
I checked them several times, & did it paralell with wrist pin. Now I need to find the thickness of that base gasket before doing anything. If I cut heads now & go back to yamaha gasket later- well you know where I'm going with this. But at this point, I could shave .010" safely, Keep my squish good & gain approx. 10psi cranking comp???
 
ottawaair said:
I checked my squish, here are the #'s
pto -- .067"
center - - .064"
mag -- .066"
I checked them several times, & did it paralell with wrist pin. Now I need to find the thickness of that base gasket before doing anything. If I cut heads now & go back to yamaha gasket later- well you know where I'm going with this. But at this point, I could shave .010" safely, Keep my squish good & gain approx. 10psi cranking comp???
Click to expand...
I would say yes. Just be aware you will loose the safety factor that Yamaha builds into a stock engines compression ratio. You will NEED good premium fuel and your jetting will have to be safe at all times because if you get low octane fuel or it runs lean at all... you will probably do some damage.
JMO
 
Hey turk sorry to bother you but I need to ask you how far I can push this mod what's the most i can take off the head when adding 2 base gaskets I already run 95-98 octane now one tank rides how far can I take off this head safely 99 srx 700 thanks my name is brandon
 
Can anyone answer my question tho on the heads what's the most i can take off with 3 base gaskets
 
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