Rebuilding 2000 Yamaha GP1200....

[GigHarborPWC]

Hi, I`m new to this forum. You have a great site. I have a pair of Seadoo GTX`s that I maintain and ride but am currently putting back together a GP1200 that came to me in boxes. It belongs to a family member and he blew it up 2 years ago. He says it threw a rod. It was a rebuilt engine and he said it had hardly any hours. A friend of his put the engine in and I have no idea how good a job was done or how it was broken in etc. When I got the ski the engine was removed and the bilge was full of oil. The exhaust parts had been sitting in dirt and the bolts were rusty. He had already purchased a brand new SBT engine so that part is good. I have been cleaning up all the parts and looking to see what needs to be replaced. The carbs have been sitting so long that I`m sure they need to be rebuilt. Misadjustment or intake leaks may have been the cause of the engines` destruction or possibly an oiling problem. It also has had exhaust modifications. It looks like the cat converter has been removed but I haven`t pulled it apart to see if a D-Plate has been installed. If they left the exhaust wide open would the engine run too lean without the restriction? There is an extra water box so it appears that has been replaced as well. I have the Yamaha Service manual but some tips from the Yamaha guys will be appreciated. Also a source for tools (flywheel puller and holder, coupling holder and replacement reeds etc.) Thanks to everyone in advance-Mark

[Technical Support]

Re: Rebuilding 2000 Yamaha GP1200....

Mark, SBT sells reeds and we can guild you through re assembly of the unit. If you have specific questions please post them, If you need to call feel free. Tom SBT tech.

[GigHarborPWC]

Re: Rebuilding 2000 Yamaha GP1200....

Thanks Tom. I`m sure I`ll have to replace the reeds and the aluminum plate that goes between as it looks like someone took a grinder to it. I`ll bet it was leaking some air. Also there is an aluminum wedge inside the reeds that looks like it has been ground on as well.
I was pretty sure I would need to rebuild the carbs. I`ve shot all the fastners with some penetrating lubricant. Whats the recommendation for greases and oils? I normally try to use the manufactures greases and lube. Another question I have is the reliability of the oil injection pump. Would it be better to block it off and mix the fuel? Or if I continue to use it since the condition is unknown, should I replace it?
Thanks again- Mark

[dsolie]

Re: Rebuilding 2000 Yamaha GP1200....

Mark, you from Gig Harbor, WA?

[GigHarborPWC]

Re: Rebuilding 2000 Yamaha GP1200....

Hey Dan. I am from Gig Harbor.

[Technical Support]

Re: Rebuilding 2000 Yamaha GP1200....

Mark, the oil pumps are reliable and it's personal preference on to eliminate or not. Some people with the older skis feel safer to just pre mix. The O.E. oils and grease work fine, The O.E. stuff, for watercraft have anti gel additives for salt water applications. Tom SBT tech.

[dsolie]

Re: Rebuilding 2000 Yamaha GP1200....

Mark,

You need to have the D-plate installed or the CAT. A free flow exhaust would make the ski run like dooky. You also need to install a resistior in the CAT wiring harness to trick the EGT's into keeping the A/F mixture right. The resistor you need is dependant on the year of the 1200 you have.

I am building a 76-80mph 03' 1300EFI right now.. A lot of fun. Lot's of go fast parts on that ski. If you need anything, let me know.

Dan

dans@designbyothers.com

[GigHarborPWC]

Re: Rebuilding 2000 Yamaha GP1200....

Hey Dan thanks for the reply. I`ve just about got everything cleaned up and ready for assembly. The stock cat was gutted. There was also a different muffler & no water box installed. I have the stock parts and I`m going to reassemble the exhaust stock with only the D-plate and chip.

I`ve been looking for the reason this ski has been blowing up. I think the exhuast was pretty much free flow with no cat and I`ll bet that nothing had been done with the intakes and carbs as it appears all stock. I think that with the exhaust mods and no carb work it ran lean. There is a twin on the trailer next to it that runs well and looks like it is completely stock (except the instrument cluster is dead). I`m trying to make the other boat reliable and I don`t want a motor blowing up when it`s my work.

Where are you getting your parts? The South Plaza Yamaha dealer has the best prices I`ve found yet. The dealer in Fircrest (Tacoma) doesn`t stock anything. I`m debating whether to do some reed stuffers. I plan on replacing the reeds and cages (the gaskets on the cages are bad). Probably going to do the oil pump as well. I still have to tear down the carbs. They have been sitting for 2 years so that should be fun.

I`ve had my Sea Doos for years but so far I like this Yamaha. Should be ready in a couple of weeks for a test ride. Where you at in Olympia? I`m on the sound south of Gig Harbor. It would be a fun ride to Olympia -Mark

[dsolie]

Re: Rebuilding 2000 Yamaha GP1200....

I get yamaha parts at slightly above cost (friends in dealerships are nice).. The A/M performance stuff I get over at green hulk. They build the worlds fastest ski's and everything is tried and tested extensivly.

For your reed area, I would suggest getting a powderlite spacer. best bank for the buck. It is just a 3/8" billit spacer that brings the reeds back away from the tunnel a bit.

The exhaust NEEDS to have some restriction other wise, it will destroy the motor. The D plate was designed to do just that. Make sure you chip it though, or she'll run like crap. The chip tricks the EGT's into thinking you are running a certain temp at all times, so the EMS continues to let the ski do whatever it wants as far as fuel/air supply and demand.

the ski I am building is an 03' 1300EFI. The mods are as follows:
D-Plate with 1k resistor (not the chip setup, made my own)
Welded crank
Powderlite spacer (stock reeds)
Race EFI filter (eliminate the massive airbox(es))
EFI controller
HO pump with a 14/20 dynafly
Jetworks pump pressure releif mod
Custom, massaged 800 grate
custom, massaged R&D / JD mod ride plate (shimmed)
reinforced pump tunnel
re-aligning the pump shoe
modding / angle the sponsons

This ski should pull mid 70's with the stock head, and once everything is shimmed under the ski. I have a hi comp head for it as well, that I will put on after the tuning that will probably require me to upgrade to the 14/25 dyna and put me in the high 70's.

The goal is to be mid 70's with 2 people on it, on 92 octane.

I am also a SD guy, this is my first triple that I have built, but so far, it's pretty easy (yamaha makes some good decisions on motor building). All of my ski's are moddified and I love it that way.

I ride on Black Lake and have a private launch about 2 blocks from my driveway.. The ski's only touch salt when a large group of us head over to Longbeach or Westport and hit the massive surf.

[GigHarborPWC]

Re: Rebuilding 2000 Yamaha GP1200....

Hey Dan, I thought that exhaust might of been the reason the 1st and second motors blew up. It looks like the reed stuffers had been chattering against the reed plate as well. Somebody ground on the stuffers and the edge was almost paper thin and chipping a little bit. They definetly didn`t know what they were doing. I have not torn down the carbs yet to see if they were rejetted but they look stock with original paint.
I`ve got a question about the instrument cluster. The one running boat of the pair has a dead guage (don`t know about the one I`m rebuilding). The boat runs fine otherwise. I`ve checked fuses, plugs, etc. Anybody have some troubleshooting ideas. The manual just says if it isn`t working replace it.
If you ever feel like riding in Puget Sound let me know. I`m over by Fox Island on the water. -Mark

[dsolie]

Re: Rebuilding 2000 Yamaha GP1200....

I have heard of the yama gauges going bad, and I have heard the same as you.. Replace...

Fox Island huh? Nice Area!! I designed a home remodel up there on Pilchuck Dr. Fi. a few years back.

[GigHarborPWC]

Re: Rebuilding 2000 Yamaha GP1200....

Hey Dan. I pulled that cowling and guage out. It had power at the plug ok. It looks like it got wet inside the guage.There is corrosion inside on the circuit board so it`s done. If you hear if anybody`s got one let me know otherwise I`ll go to Yamaha.
I have a sister inlaw that used to live over there on Fox Island and I still have a bunch of friends I went to school with over there. I`m a lifer in Gig Harbor. Come out to the sound and play this Summer -Mark

[dsolie]

Re: Rebuilding 2000 Yamaha GP1200....

Mark,

I'll come to the Psound, if you hit an ocean ride with us..

Trust me when I say the bay is boring after you hit those Pac Ocean waves..