11-14-2010, 03:18 AM #1
- Join Date
- Oct 2008
gp1200 pump..to seadoo pump.... thoughts?
ok, every time i am on here i come across someone making the comment on how inefficient the yamaha pumps are, especially the older units like what is on my 1999 gp1200.
what does everyone think about... oh i dunno... changing the pump out for a seadoo pump or a polaris pump?
the seadoo pumps from 04ish are 158ish mm so sleeving is necessary (but possible) and they are 12 vane stator from the factory. Seems like it would be minimal work to machine the thing to accept the yamaha hardware.
basically make it bolt up to the front intake ramp is part one.
part 2 is to machine the internals or modify them in such a way that the stock yamaha driveshaft and impeller can be used. A plastic liner could make up the size difference of the yamaha impeller vs the seadoo impeller (155mm 158ishmm).
failing that, have a yamaha driveshaft modified to accept the spline of the seadoo pump so it all links up together nicely. Doing this mod can even allow you to move the pump further back if you want.
step 3 is to machine off and plug up all the unnecessary holes and plumbing on the seadoo pump, and make the coolant feed line to the engine.
lastly... step 4 attach the yamaha control cables to the seadoo trim and steering controls... easy peasy.
after that is simply a matter of finding the correct prop pitch.
11-14-2010, 01:28 PM #2
I don't find the 97-99 GP1200 pumps inefficient in stock to mild form. If your running triple pipes, yes you will have some cavitation and not be able to take advantage of the pipes coming out of the hole. If you were to go to skat-pump or a sea-doo pump and your ski is not highly modified, you going to lose topend speed, but it will hook up better in chop and holeshot a tad better. Not worth the money and hassle unless you are making big power. My ski does not cavitate at all coming out of the hole, stock pump.
11-14-2010, 01:29 PM #3
11-14-2010, 01:56 PM #4
Addicted on the forum has the know how on adapting an 05-08 GPR pump on the 97-99 GP. He has made this work before. Knowing there is a way to adapt the 05-08 GPR pump on the 97-99 GP, one would think it may be possible to get the Sea-Doo pump to work, but your going to have to start with a 05-08 GPR pump. Again, unless you have a beast of a GP, I don't believe this is money well spent. Just my opinion.
11-14-2010, 10:42 PM #5
- Join Date
- Oct 2008
I do not have 1500 to drop on a skat pump.
I already am quite familiar how my gp1200's stock pump runs in the rougher waters I deal with.
I do have 300 dollars though, if I can get a newer seadoo pump that has a more efficient 12 vane stator section and then set it back further to improve the intake volume I am already sure the hookup will be improved.
So if I can get a pump for 100-150 dollars used, machine it for free to dock up to the existing intake duct setup, I am already in the game less the impeller.
I can even try using my existing set of impellers to get an idea on how to get it setup.
I dunno, in my mind it is worth a try. And I dont see the possibility of a speed decrease with a properly setup pump. If the pump is more efficient then that means less energy is wasted in heat generation, friction, cavitation ect. I might not go any faster but my hookup in the rough is what i am concerned about.
I am still very open to anyones thoughts, I'd appreciate any ideas
11-14-2010, 11:20 PM #6
Hey there Natrix...
I think you are trying to reinvent the wheel somewhat here..?
I'm certainly not saying it can't be done..!!
Just seems a little bit of a mammoth task..?
Even if you could go straight out and buy the 12 or 14 vein skat pump.. (if the cash was available)
Unless your ski was reasonably modified..
i.e. some porting, increased compression, maybe some upgraded reeds, then some carb work,
I would imagine a stock GP1200 with a skat 12/14 vein would NOT perform all that well..
More than likely just load the motor up, also likely would be a possible loss of up to 500 or so RPM on the topend.
The same could be true of any pump with a high vein count..??
(maybe not though..??? )
Now then the 05-08 pump Brandon was referring to is now installed on my GP1200..
That pump is running a 13-19 dynafly impeller..
I expect to drop somewhere in the region of 250-350 RPM's by running the dynafly
No big deal as I'm over 7050rpms anyway
If by some miracle the weather improves a little over here, I'll get it out for a test run this week sometime..
Before the water becomes the hard variety..
As a closing though...
I have seen on here.. the occasional skat 12 or 14 vein stator section for a GPR sell for in the region of $300 for the pump stator only..
Mod one of those, similar to the 05-08 HO pump i have and you are all set.. change out of $500 easy, possibly even inc. a prop..??
11-15-2010, 09:11 AM #7
- Join Date
- Oct 2008
Mild porting, check
ported engine cases, check
gasket matched and cleaned up exhaust manifold, check
Jetworks valve, check
MSD 3 channel ignition with custom pickups, maintaining the factory charging system, check
Modified stock pipe to run dry, check
water injection system, check
adapted 760 tuned pipe to the 1200, check (yes the math actually works)
in the process of building my own tuned pipe, to connect to the stock U-pipe, check
so for the time being, yes i am going to work on getting the power out of the motor, however again, I am not doing this for speed increases, i am doing this for rough water hookup.
11-15-2010, 12:23 PM #8
11-15-2010, 01:44 PM #9
That lot should already be making one tasty GP as it is..
I'll 100% agree with Brandon then and say GO for it..
I still think modifying a skat stator from a GPR might be the best option.. (best being easiest.?)
Would be interested to see a few pics or a video of this ski..
It really sounds like my kinda thing..
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By SvrdRam in forum Yamaha PWC Performance (2-stroke)Replies: 1Last Post: 07-05-2008, 04:32 PM
By ABBOTT in forum Yamaha How To & FAQsReplies: 11Last Post: 02-04-2008, 06:46 PM
By JDS GP1200 in forum Yamaha Old School SkisReplies: 34Last Post: 11-21-2006, 08:03 PM
By OsideBill in forum Yamaha Open DiscussionReplies: 4Last Post: 10-25-2006, 11:55 PM