GPR\XLT Carb Upgrade\ Accelerator pump removal

[LT1GMC]

7/8 turn low and 1 1/4 turn high.

Stock carb's, cleaned and completely rebuilt. Stock reeds, stock manifold.

Acc. pump removed
Chokes removed
Carb restrictors drilled out 1/8"
95 main jet return
Oil injection removed
Fuel selector deleted
Extended and clunked dual fuel pickup's
Dual Yamaha filter/seperator's
Modified stock air box lower half, with stock screen and lid
Front intake ducting removed

110 pilots
120 mains
95g springs
1.5 n/s _ 44psi pop off
95 return restrictor _ 1+ psi at idle

Hey man, what were your high speed and low speed settings?

[capec38]

Im new to Greenhulk but have been working in yamaha XLT1200 and GP1200R for a few years now. On a stock engine, changing nothing, what is the best settings when rebuilding or cleaning the carbs? referring to the pop off (ive read yamaha says 65-75) low speed (one turn), high speed MAg and center (1 1/4 turn) PTO cylinder (1 1/2). is this the best? I'm getting more and more of these skis in for carb work and i dont like taking them apart twice. Any help would be appreciated

[harrystruman]

I am also new to the site and as most from what I'm reading here the world lost a guy who knew his poop when it came to these watercraft ,rip osidebill.. but hopefully some other members here have either tried or have been successful with issues with our boats and can help as well as bill did..
So here is my question , I have two boats one a 99 xl1200 pv that I followed the recipe and have a screamer, but bought a 03 xlt1200 with what seems to be the same issues as the 99 had with running terribly rich and fouling plugs, so I installed the d-plate and the chip and started with the carb mod and it hit me , Is the recipe the same for this motor as it is a 68n instead of a 66v ? Has anyone done the mods to this engine with success ? Thanks for your time guys

[LT1GMC]

Exact same engine, 99 XLL and 03 XLT. I have "04 XLT with the carb mods and 2 99 XLL's in family with same mods.

I am also new to the site and as most from what I'm reading here the world lost a guy who knew his poop when it came to these watercraft ,rip osidebill.. but hopefully some other members here have either tried or have been successful with issues with our boats and can help as well as bill did..
So here is my question , I have two boats one a 99 xl1200 pv that I followed the recipe and have a screamer, but bought a 03 xlt1200 with what seems to be the same issues as the 99 had with running terribly rich and fouling plugs, so I installed the d-plate and the chip and started with the carb mod and it hit me , Is the recipe the same for this motor as it is a 68n instead of a 66v ? Has anyone done the mods to this engine with success ? Thanks for your time guys

[Reaper9789]

just did this tonight.. putting it all back together tomorrow and hopefully take it out on saturday, or maybe even tomorrow.. hope to gain 2 mph at least.. also get rid of the random sputter at low speed.
new plugs coming in next week.

[jettdreams]

So on a yamaha 1200 PV motor the following setup with The airbox REMOVED(same as installing flame arrestors I assume) should work well correct? I dont really get water in the hull so water ingestion shouldnt be an issue.

o 110 Pilot jets, 1 turn out on low speed adjusters
o 120 main jets, 1-1/2 turn out on high speed adjusters
o 1.5 Needle and Seat, 95 gram spring (Dull Silver) 42-45 avg. pop-off pressure.

I have read so much about carb setups/adjustments on these motors that my head is going to explode.

[LT1GMC]

Water ingestion might not be a problem, but a misfire/backfire igniting the oil and fuel film in the boat and blowing it up will be. The name "Flame Arrestor" is because the are designed, and necessary, to keep an inboard engine from catching the boat on fire.

So on a yamaha 1200 PV motor the following setup with The airbox REMOVED(same as installing flame arrestors I assume) should work well correct? I dont really get water in the hull so water ingestion shouldnt be an issue.

o 110 Pilot jets, 1 turn out on low speed adjusters
o 120 main jets, 1-1/2 turn out on high speed adjusters
o 1.5 Needle and Seat, 95 gram spring (Dull Silver) 42-45 avg. pop-off pressure.

I have read so much about carb setups/adjustments on these motors that my head is going to explode.

[jettdreams]

I will put on the metal screen, just not the entire airbox. Its a chance im willing to take if it makes this thing run properly.

[Reaper9789]

Honestly the metal screen is probably the most restrictive thing in the air box. I would remove it and keep the box on without the intake tube and silencer. Allthough flame arrestors will make your life alot easier for tuning.

[jettdreams]

If thats the case Ill just leave the screen off and the airbox off. Ill take the gamble with it blowing up I guess.

[80degrees]

Hi guys need some quick help with my gp1200r. Iv just rebuilt the carbs to bills specs

and iv just done a pop off test and the pop off is hitting about 35psi and spraying everywhere. Iv got 95g spring and 1.5 seats. Why would the pop off be so low? Shoul ding it be around 42? How can I make the pop off higher?

[Reaper9789]

What tester are you using? Did you make your own? Is any fitings leaking? Are all the carbs the same?

[LT1GMC]

Carefully stretch the springs a bit until you get the pop off where you want. Bill shared with me the springs vary from the factory now days.

Hi guys need some quick help with my gp1200r. Iv just rebuilt the carbs to bills specs

and iv just done a pop off test and the pop off is hitting about 35psi and spraying everywhere. Iv got 95g spring and 1.5 seats. Why would the pop off be so low? Shoul ding it be around 42? How can I make the pop off higher?

[ahowe2013]

So im fairly new to this site as well and I've read this whole post and have a few questions. I'm rebuilding a 99 xl ltd. and am having a problem with the #3 cylinder getting hotter than the other two and it has blown a cylinder and two pistons already. I shut it down last time before it would do it again. I am guessing this is a lean problem. I have a D plate and chip, waveeater clips and couplers and oil block off kit. but that is all. Should I have to do anything to the carbs so that it is not running so lean on the rear cylinder? thanks

[ahowe2013]

Havent tested it yet. I just learned that I need to do the pop-off test and a leak down test. Made my own tester and it holds air well so that should do fine. All the carbs are the same. I'm going to go in and check all the springs and arms and make sure nothing is bent. I did rebuild the carbs and put in the springs that came with the Mikuni Rebuild kit. they are the gold ones which apparently are the stiffest. The ones I took out were gold also though. Are these the stock springs? should I put lighter ones like the 95G ones in? what pop off pressure should I be aiming for? thanks.