Super Jet what´s wrong with my ski?

[sniper]

Brian has a XS900R, and Bill has a JM781BB. Bill's ski feels like it is going to rip your arms off. Brian's ski feels very tame. Side by side, Brian's ski destroy's Bill's ski in every way. The PV make smooth delivery of power so what has more power, feels like less.

My Gp1200 feels very fast, but the reality of it is that it is not. Yes, it does almost 60, but in rough water it's more like 50. It just plows and hops and feels like a pissed off bull. In your mind, you know it can do 60, and you are getting your ass kicked so you must be doing 60, but meanwhile the guy on the 787 Seadoo Xp with 30 less HP things his ski is slow because it only does 55 on the flat, it feels so much slower than the 1200 on the rough, but in a rough water race, they run side by side. The XP hull design makes the ride smoother, so it feels slower, but it's not.

Are you sure it wasn't just in your mind that it was more powerful? You only have 50 more displacement and PV. You should have more power but not OMG this is so insane I can't believe how amazing this power is I just myself more power. It's going to make some more power, but it's not going to feel like more power. The BB yamaha motors feel powerful because it gives you everythign right away then taps out. The PV motors give you the same amount but don't feel like it, and then they just keep going for so much longer. I just know that 900R feels like it has less than that 781BB, but I know that is simply not true. It's like removing a waterbox and gaining 50HP, even if you loose 5hp. It just seems faster.

What I'm saying is, maybe the problem is your expectations of the motor and the illusion of smooth power with less noise?

PS. The XS900R was built by Xscream and the JM781BB was built by Blue. They were both tuned by Chuckie of XS. They both run correctly, and I compared them both on the same day.

If the engine is supposed to performe this bad then I made a bad desicion when I bought it,
But everybody who have tried my ski think there is something that is not right with the bottom end power.
Now I don't know what to belive, if it's maybe like you are saying..

 

[sniper]

Aren't dasa motors ported different? To make power in mid range and higher rpms? I "thought" someone was telling me here recently with the way flat water has gone ( flip to flip to flip to barrel roll to flip to flat spin 360 to flip) that your more in the mid to higher rpms rather than brap brap brap- let off- brraaaaaaap. If that makes any in sense at all.

Yes I've heard that to, hence my questions about changine the porting.

 

[lazyt747]

Are you positive that all of your fuel lines are run correctly?

 

[ProSouth]

I'm kinda thinking those carbs are HUGE too. 44's would feed that motor all it needed. Maybe if you had a 5 mil stroker. Even then 46's or 48's would be sufficient.

 

[lazyt747]

I'll trade you a girdled ADA 701 running like a raped ape for that DASA

 

[sniper]

Are you positive that all of your fuel lines are run correctly?

Yes 100% the only thing is that I have no restrictor in the retur line, but I tried with one earlier but no difference.

 

[sniper]

I'll trade you a girdled ADA 701 running like a raped ape for that DASA

Thank you but no thanks if it had been a xs1200 maybe

 

[lazyt747]

The reason I ask is because I had my fuel lines switched up before and it acted the same way you are explaining it to be. If you are positive that they are correct (which I was too then realized they were incorrectly hooked up) and the plugs, compression, and spark are good then I am with everyone else when they advise that your carbs are entirely overkill for your set up. Drop down to 44's and it should run fine with proper jetting.

 

[sniper]

The reason I ask is because I had my fuel lines switched up before and it acted the same way you are explaining it to be. If you are positive that they are correct (which I was too then realized they were incorrectly hooked up) and the plugs, compression, and spark are good then I am with everyone else when they advise that your carbs are entirely overkill for your set up. Drop down to 44's and it should run fine with proper jetting.

How was your fuel lines when they were wrong?

 

[lazyt747]

I don't exactly remember. Post up some pics of how you are running them now. Are you running a stock fuel pick up?

 

[sniper]

I'm running a wamilton internal fuel fill with pickup and I have a external fuel pump. I'm not near my ski but I will take some pics when I am.

 

[Matt_E]

Are you running return line restrictors?

 

[sniper]

Are you running return line restrictors?

No not at the moment, I tried with the one that was supplied with the carbs but no difference. Should I try that one again?

 

[lazyt747]

Get pics

 

[Vumad]

I'm kinda thinking those carbs are HUGE too. 44's would feed that motor all it needed. Maybe if you had a 5 mil stroker. Even then 46's or 48's would be sufficient.

I mentioned that back on the 1st page, but still no one has directly answered that. Does anyone know if a motor that small will run right with 49s? Brians XS900R is only running 44s, and Chuckie wants him to go to 46s. Over 100cc more and still no more than a 46mm carb. JM likes 38mm on his 781, or maybe a 44mm on them.

So, can someone answer the question. I think it's very relevant. Can a 771 motor run right with 49mm carbs? I don't know enough about it to say for sure, but my limited knowledge wants to say that is the problem.

 

[ProSouth]

I mentioned that back on the 1st page, but still no one has directly answered that. Does anyone know if a motor that small will run right with 49s? Brians XS900R is only running 44s, and Chuckie wants him to go to 46s. Over 100cc more and still no more than a 46mm carb. JM likes 38mm on his 781, or maybe a 44mm on them.

So, can someone answer the question. I think it's very relevant. Can a 771 motor run right with 49mm carbs? I don't know enough about it to say for sure, but my limited knowledge wants to say that is the problem.

i know you mentioned it, i wasnt trying to steal your thunder, lol just trying to make it a reoccurring thought between more than one person. i feel it would run, poorly. what jets are in those monstrous carbs?

 

[sniper]

Now I can't find the restrictor, does somebody know what size it was maybe everybody uses the same size.

 

[egbrig]

A #60 to #80 restrictor will work. Yes 49's work great on even 701's, it just depends on how you run the boat. We run 49's on our Spec-Sport class blasters (701-718cc's, no porting, with b-pipe, msd enhancer, and 185psi comp.) and these boats rip off the line. There is a lot of good advice and good perspective info on this thread.

 

[sniper]

A #60 to #80 restrictor will work. We run 49's on our Spec-Sport class blasters (701-718cc's with b-pipe, msd enhancer, and 185psi comp.) and these boats rip off the line.

Thanks then I know that my carbs are not to big
I looked at some old mails from the enginebuilder and he was 100% sure the jettings was correct. Maybe it will come alive if I put in the restrictor if I find someone who sells them around here.

 

[sniper]

So tonight I have been searching for that restrictor but could not find it so I ended up with a temporary solution, Zip tied the return line and I also removed the cover around the flame arrestors( just to try with out them). Then off to the lake for some testing and it worked much better still a little weak on the bottom but much better then before. I think I need higher compression and/or change my timing curve. It was a thread about curves (can't find it of course) but there was a curve that waxhead was using, I'm going to try that one. If someone has tried it let me know if you liked it