glsmohio
Well-Known Member
thanks for the info matt. I am only running a spec 1 though. From what you said though, I think im going to go with the 6 hole gasket. That will be me .053 - .059
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97 Seadoo Spx build
- Thread starter glsmohio
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thanks for the info matt. I am only running a spec 1 though. From what you said though, I think im going to go with the 6 hole gasket. That will be me .053 - .059
AdamXP800
Well-Known Member
Yea I would call group k as well. I know they have done a lot of testing with different set ups. Matt Braley is the guru though when it comes to aftermarket set ups. His modded skis ran flawlessly at the ride in November. His Gsx was a beast and that Hx was the snappiest little ski that I've ever ridden
95 XP800!!!
Keep the 2 strokes alive!
95 XP800!!!
Keep the 2 strokes alive!
glsmohio
Well-Known Member
Yea I will give them a call to make sure...last time I talked to him he thought I was way big with putting 44s on the ski but then again he said he's more after safe rec boats.
That is correct. Their specialty was endurance racing so they were always after reliable and somewhat safe performance as opposed to peak numbers. Like you said, perfect for fast rec boats.
I tend to agree as I have gotten older/wiser/lazier. I don't miss the days at the lake tuning and checking plugs to squeak 1 more mph. I like stock now and just add gas and oil and have fun with the family. So much less stress for me.
I tend to agree as I have gotten older/wiser/lazier. I don't miss the days at the lake tuning and checking plugs to squeak 1 more mph. I like stock now and just add gas and oil and have fun with the family. So much less stress for me.
glsmohio
Well-Known Member
ok guys I just got off the phone with Harry at Group K. Told him my set up of what I had ( using his head that he did the 91oct mod on) and running the factory spec 1 pipe. He said with adding the pipe to his head that my ski is a total race ski and i should be running a 50/50 mix with race gas. He also told me that he would still set the squish around .040". I asked him what kinda psi i would see and he wouldn't give me a number but if i set it at the .040" its going to be very healthy. So now I'm looking for your guys help. When i started this build i really didnt want to pay $8 a gal for 104oct. I was ok with running the 93 pump gas. So i guess I'm asking some of the gods on here to give me some info to see if I can make this run on pump gas by its self or maybe add a little race gas to it. can you use octane booster? I just don't want to put $60 in the take for an hour of fun lol, but i guess in a way thats why i have 6 skis.
[MENTION=50799]fitty650sx[/MENTION] [MENTION=57920]racerxxx[/MENTION] [MENTION=51824]Matt Braley[/MENTION]
fitty650sx
Active Member
Octane booster does dick all. It might make 87 into 91, but it will only make 91 into 92 at best.
Run a stock head. Problem solved. There are no inbetween mods. You either want to go fast, or you don't. Run the spec 1 without the water injection, stock head, and follow FPP instructions.
Run a stock head. Problem solved. There are no inbetween mods. You either want to go fast, or you don't. Run the spec 1 without the water injection, stock head, and follow FPP instructions.
Krispy
Well-Known Member
Sell me the head or pipe 
Personally I would run the Spec 1 with a stock head. I have heard nothing but good things about them.
Also, you will have more luck running a factory pipe with other mods (since it is a fairly common setup,) than running a group k head.
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Personally I would run the Spec 1 with a stock head. I have heard nothing but good things about them.
Also, you will have more luck running a factory pipe with other mods (since it is a fairly common setup,) than running a group k head.
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glsmohio
Well-Known Member
what kinda set ups do you run? how high of octane do i need to run with the pump gas?
glsmohio
Well-Known Member
Sell me the head or pipe
Personally I would run the Spec 1 with a stock head. I have heard nothing but good things about them.
Also, you will have more luck running a factory pipe with other mods (since it is a fairly common setup,) than running a group k head.
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ill keep that in mind krispy
The pipe is your best mod so +3 on keeping that and running a stock head. Luckily you can swap heads with out breaking any gaskets so you can check squish and compression on both and compare. I don't like squish under .050" or compression over 175psi because you risk detonation on pump gas.
Do you have water injection now? if so use I'd use it because it does hit harder off the bottom. If it fails down the line you just loose a little acceleration but the pipe won't overheat or anything because you should be running a constant flow from a filtered inlet source to another jetted fitting.
Thanks Adam.
Do you have water injection now? if so use I'd use it because it does hit harder off the bottom. If it fails down the line you just loose a little acceleration but the pipe won't overheat or anything because you should be running a constant flow from a filtered inlet source to another jetted fitting.
Thanks Adam.
fitty650sx
Active Member
Spec 2, stock head, stock carbs, flame arresters, I ran 94 octane. Not so much for my compression, but for the little bit of ignition advance the microtouch brings in. It will also cover your ass if your prop is a little too steep.
glsmohio
Well-Known Member
thanks guys for all the feed back, I do have some questions. 1st off has any one ever ran a group k head? Yesterday when I talked to harry he wouldnt give me even a range with compression with his head ( I found that kinda crazy???). After talking with my dad and brother I wish I would of asked Harry what cc he made my head ( I think im going to call today and ask that question). Has anyone every had the cc checked on a group k head mod? Also does any one know what the cc of a stock 787 head is? Im going to call Napa today and see how much they want to check the group K head vs a stock head for cc if group K wont tell me. By any means Im not trying to bash group k just trying to find some numbers of what I got. Thanks guys
fitty650sx
Active Member
You really need to get rid of that head [emoji53]
Krispy
Well-Known Member
Don't pay Napa to check the volume of a head it is crazy simple to do on a Seadoo.
Just flip the head with the domes up and plugs in, (I sit it on drinking glasses) smear grease or Vaseline around the sealing surface of the head and then place a piece of plexi glass over the combustion chambers.
The plexi should have a small hole drilled in it to allow you to fill the head with liquid. I use windex as it is colored and easy to see when it is full.
Use a large syringe (picked up at a vet supply place like tractor supply) to measure how much windex it takes to fill each combustion chamber.
PM me your number and I can talk you through the process if it doesn't make sense in text.
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glsmohio
Well-Known Member
Thanks man I know what you talking about, i was just going to pay napa to make sure it was right but h*ll I give it a try, sounds way to easy. Ill pick the stuff up tonight (work till 8 tonight) and i hope to get it done tomorrow.
glsmohio
Well-Known Member
I'm not saying im going to keep it but now I would like to know what the numbers are.
I'm curious to hear how many cc's are in a stock 787 dome. I know it's more then 44 because 44's seem to raise the compression at least 10-15psi. I have aftermarket dome sets in 45 and 46cc. I've often wondered if the 46's were any smaller then stock.
fitty650sx
Active Member
Maybe I'll tackle that tomorrow.
glsmohio
Well-Known Member
I think i might do it tonight, depends if i get out of work on time. Damn car sales lol. Matt i just posted the info on that hood in pwc today by the way
glsmohio
Well-Known Member
Ok guys I just got done toying with the heads and to find out the cc, I tried my best with what my wife brought home from work(she's a rn) I wish it would of been bigger so I could hold 50cc at a time but I could only do 10 at a time. Let me know your thoughts...the set up that i had to start with.
I started with windex and I had problems with it wanting to bubble so I went with alcohol.
The stock head I'm going to call it 47cc,remember I already put 4 , 10cc (makes sence with the pic)
The group k head was 43cc.
I made sure all air bubbles where out...thoughts?
I started with windex and I had problems with it wanting to bubble so I went with alcohol.
The stock head I'm going to call it 47cc,remember I already put 4 , 10cc (makes sence with the pic)
The group k head was 43cc.
I made sure all air bubbles where out...thoughts?
Looks like you did a great job and the results are about what I figured. It's nice to know for sure.
Krispy
Well-Known Member
Yep looks good. Thanks for taking the time to test it.
The only reason I suggested to do windex was for the color, a couple of drops of food coloring would work in the alcohol too.
It would be nice to see an SBT head measured too to verify they are cutting for increased cc.
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The only reason I suggested to do windex was for the color, a couple of drops of food coloring would work in the alcohol too.
It would be nice to see an SBT head measured too to verify they are cutting for increased cc.
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