Thread: Wanna review my GP1200 setup?
01-02-2011, 11:47 AM #1
Wanna review my GP1200 setup?
After hours of GreenHulk reading and planning, here is my '97 GP1200 (65U) build setup and plans. Does anyone see any errors or have ideas I'm missing (besides a milled head)?
84.5mm on all 3 cylinders Pro-X pistons
New Yahama gaskets and seals for entire engine
Might convert to Premix
Primer kit, chokes removed
Riva Cone Flame Arrestors
Mild Case porting (mostly just cleaning up the casting flash)
All 3 carbs will be rebuilt with:
- 100 pilots, 135main, 1.5 needle & seats, 115 gram spring (Stock was 100, 95, 97.5 pilot and 135 mains, 1.2 needle seat)
- Return restrictor drill out mod with 105 main jet inline restrictor to balance fuel pressure
- T handles carb screws
- Double up on the check valves
Aluminum Trim Tabs
Aquavane intake grate
Raider exhaust manifold gasket
YD SC XO prop
01-02-2011, 01:44 PM #2
01-02-2011, 08:30 PM #3
Don't bother doubling up on the check valves and definitely convert to premiix.
01-02-2011, 09:31 PM #4
01-02-2011, 09:45 PM #5
- Join Date
- Apr 2006
- panama city beach 'fl
have head machine for more compression (150 psi and have squish machined) set of v-force reeds,and keep a eye on hull 97 had some problems
01-02-2011, 10:33 PM #6
If you set her up to get the nose up out of the water and pitch the prop just right it could hit 65 on a good day.Raising comp to 150-160 psi would make 65 that much easier and you will get there quicker too.My 70 mph ski doesn't have double check valves big carbs or aftermarket reeds.My 97 is a 65+ mph ski if I just set it up to get the nose out of the water.I recomend a aftermarket head with interchangeable domes so you can easily change comp,stock is 120 psi and it sucks,raising it to 150 psi wont add much on top end but will wake up the ski all around.You can go up to 170 psi later with new domes and some higher octane gas when you want more power.
01-02-2011, 10:47 PM #7
Alright so I'll skip the double check valves for now and try to come up with some more money for a milled or aftermarket head....wife's gonna kill me if I keep spending money on this thing
01-03-2011, 12:31 AM #8
Noticable improvement when you raise comp.Watch ebay over winter and you should find something for not to much money.
01-03-2011, 12:36 AM #9
What ride plate ?.You want a good ride plate so you can shim it for top speed.
01-03-2011, 08:53 AM #10
- Join Date
- Jan 2010
- South Carolina, USA
i definitely recommend an aftermarket ride plate. personally i run an r&d plate with a group k mod. definitely gets the nose up and helps with top end. good luck with the build.
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