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Bought 2 Yamahas 2 Stroke XL1200 and GP1200R both from 2000 and need help

31371 Views 216 Replies 5 Participants Last post by  gica
I just registered with this forum and want to say hello to all. I have a lot of experience fixing cars, diagnostics, rebuilding, painted cars, worked on boats own one but HAVE NEVER OWNED OR WORKED ON A 2STROKE PERIOD. Need help, better to ask rather than waste time guessing. Have the service manuals for both 2 strokers
That said I bought 2 different Yamaha jet skis the 2000 XL1200 3 seats and the 2000 GP1200R 2 seats. Both have been sitting for awhile, so I did compression on them with a not so new and cheap tester so I will have to redo it with a better one. My tester is for automotive compression and I saw something online that said because the hose of the automotive ones is a little longer, it might read below accuracy on a 2 stroke so you can add some value to it after the reading(?!). Not in car engines you don't
- Anyhow the compression on all was 90+, only one had reading of 100. That is low I know as I have read needs to be at 115-125 for a healthy engine. When the needle gets to the 90 it quickly jerks back and forth and doesn't stay still. Kind of like when you use a vacuum tester to find leaky valves or a vacuum leak in a car. Needle is not steady. It might be the tester itself.
- So I don't want to rebuild the upper end right away if possible, I can will a USB camera through the spark plug hole and see what surprises there are
- I do want to look at the carbs maybe adjust clean or rebuild
- fix the urgent issues like the oil hoses that could brake and add adapters that prevent it got to find which
- want to know about gas and oil mixing(mine have the gas and oil separate so how do I do that, can it be premixed for a better combination where the oil mixes properly, so it doesn't build up somewhere, or is pouring them separately good, do I need to siphon the old oil out also?
- The handle bar on the XL1200 is stuck to the right side. Found the cable that goes all the way to the back from underneath the steering column I will try to spray something(blaster spay) or better off change it, if I figure out how I know how to remove the back and probably the cable underneath, but in between it goes through some areas in the battery compartment and under the motor
- The XL1200 has a cat sticker and I want to replace it with a D-plate and chip if needed, because when I started the engine there is a weird rattle in that general area, could be something else of course, also it is over ten years old actually 18. The cat might already be out, don't know yet.
- I already suctioned the gas out of the GP1200R(not the oil yet) will do the XL1200 next(can the old gas be reused for anything I have 5 gallons
- when I started the GP1200R it actually sounded better but when I accelerate white smoke comes out of the exhaust will post dropbox link to video of it, looked online and a lot of the same models do the same don't know if the same amount
- The XL1200 is not showing the same smoke just the regular blueish greyish smoke(not too much either) from the burned exhaust mixture of oil and gas.
- I bought spark plugs for both, NGK (7986) BR8ES-11 I hope they're ok for both because the XL1200 had NGL R plugs nevermind the R is on the new plugs also
I think I listed most of my concerns, sorry for the lengthy text but want to cover my bases and noticed that you guys are really great at helping. Great forum here. Thanks in advance to all.
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Hey Dave are rodsatheart and Zardoz still around hope everyone is still around and ok
I did the pop off again after changing back to the original springs and they all popped at around 63. Is that ok?
63 should be ok. If you want to tune it a bit, stretch the spring ever so slightly. But if they were ok before you should be good.

Haven't heard from zardoz in a ***** age. Not sure what's up with him. I don't have any contact info for him. I have Rods number and may call if I don't see him on soon. I've pm'd him a few times no response.

Is the pop off supposed to be higher, what happens when I stretch it?
Wanted to know if I can use the sheet above from SBT and use the 1200R cc settings. I read you're supposed to look at the plugs after 5 minutes of riding and don't idle before shut off to get accurate results.
And if I decide to play with the high/low screws can it be done with the exhaust on? Doesn't seem like it.
Also the check valves I used are the old ones they don't have any markings and are the same on both sides. Did not see any videos that mentioned using a certain side. The SBT(or Mikuni? originals) ones have the blue line. Don't have those.
Because I opened the carbs a few times the BN46i/13 gasket in the picture stuck to the body of the pump assemble and when I peeled it off a little bit stuck to it. So all 3 have something like the picture peeled off but it's on the side and facing up towards the vent hole of the pump cover. This is the only one that sticks. Should I use any gasket maker on that area like Gasgacinch 440A which is recommended for the 3 carburator to intake gaskets.
or something?
Am waiting for the Pennzoil XLF oil and I will try to finally start the sucker.
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Yes, You want to use the 1200R settings from paper.

@63 for pop off you will be fine. I would leave it be. Only mentioned stretching spring if you wanted to adjust a bit higher. MUST be careful as you can go over psi very easy. Then your done and need new spring of like color. So I would leave be @ 63.

The high/low screws are very hard to get to with the exhaust on. On my 800's I can't get my big hands under to get to them. Not sure if the 1200 has any more room. They do make a special screw driver that makes it easy. But I Don't have one.
Did you document high/low screw settings before disassembly? If so put them at those settings. Adding about an 1/8 turn out to high screws.

The check valves do come new with a color mark. I've always been told the marks go out. Once in contact with fuel the marks disappear.

I don't recommend any use of sealer on carb gaskets. To easy to block small holes. I can't see damage in the pic. I would say use it as is.

Yes, the best way to check carb setting in field is a chop test. With new plugs in. Run 5 min wide open throttle. Then kill motor, no idling. And remove plugs. Checking color of plugs. They should be a dark brown. Light coloring = lean. BLK = rich.
This is NOT easily done on the water, especially if water is rough.
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So what should I do get all new check valves?
Looking at them through a magnifying glass I don't see any difference in shape.
The only way to get valves I know of is another kit. I only recommend getting true Mikuni kits. not cheaper after market kits.

I've never been able to see a difference in one side verses the other on the valves. Have always been told marked side out. Sometimes it's even very hard to tell witch is witch. I've never seen it written anywhere either.

All genuine Mikuni parts sol individually. Really nice.
So I put the carbs together after rebuild and the throttle plate on top from the last MAG carb. wasn't closing all the way as were the other 2. Is that something that is normal. I adjusted the link to close it all the way when turned.
Engine Auto part Automotive engine part Carburetor Vehicle
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When you mount them to the rack plate leave them all loose. Then move them around till they settle. All throttle plates closed no stress on linkages. Sometimes it takes a couple tries to get them right the first time.make sure the idle screw is not holding first carb open.
So I finally put the carbs back this weekend and after not being able to start at first I did a search and found out how to build pressure in the carbs by removing the plugs putting rags removing the return hose and crank untill I got gas out of return hose.
It then started right up. The idle was kind of low and it stalled at first so I raised the idle. It's at around 1300 to 1500 now. Didn't really mess with it much. So my low speed adjustment was set to 1 and 1/8 on all as per guide from sbt sheet.
When I raised the idle it was running pretty good.
I did not let it run too much as the gas is from last year and want to add some stabilizer in it and put more gas and some oil in the gas as per instructions with a newly rebuilt engine.
There is white smoke coming out which is moving away rapidly so it could be steam.
So what else should I do now?
If your still using oil injection then:
If it running well enough to ride put in 5 or 6 gallons of fresh 50/1 premix and ride varying rpm but not holding at any given speed long.

If running premix only:
mix 5 or 6 gallons at 25/1 and ride as above varying rpm.
Note: at these rich oil mix's you may foul plugs if running low rpm for long.

After that fuel is consumed go to only injected or premix at 40/1.
I have started some semi rebuild on the GP1200AY
Model and am doing cables, carbs rebuild and adjust, cleaning the oil container replacing hoses. When I opened up the power valves a lot of sludge revealed itself. Is that a problem. How do I clean it better?
Auto part Metal
Auto part Engine Vehicle Car Automotive engine part
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The sludge in the power valve link box is common. Unfortunately the only way I've found to do a good cleaning is to remove each cyl and wash them out with solvent. You can carefully remove to worst of it without dropping any inside motor. But you can't get it good and clean that way.
Looking at what's in the picture. Those appear to still be the original link on the valve. Those need upgraded links to capture the link pin. The original are open on the ends and allow the pin to fall out. See pic, link open at arrow points. Can see pin ends. You can either replace the link from SBT or use the wave eater clips that go over the existing link.
My suggestion would be to remove each cyl and clean. You need the valves to move freely for the system to work properly.


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Is this sludge something that needs cleaning as a maintenance procedure every year?
I also need to ask you about something that broke off the MAG carb on this one. It's the place where the idle screw goes into broke in half. What do you suggest? Weld if aluminum or JB Weld or Aluminum Brazing.
That is the idle screw bracket? As in idle screw threads through it?

The carb body I believe is truly a white pot metal. I don't think that anything will work short of jb weld. But it will need to be grease/oil free and paint removed from area. I would build it up heavy on both sides and over the top. Rough it up good so JB sticks well.

That sludge is probably 20yrs old. Good quality oil will help keep it from forming.
I use interceptor oil from amzoil. It's made for power valve motors. It's a low smoke, high detergent oil. If you join and become a preferred customer its cheeper then yamalube. Another choice is Pennzoil full synthetic premium plus 2stroke. I don't know that it's higher in detergents but I use it in my boat motors and there is no carbon build up on the Pistons.

Being you've cleaned the oil tank now's the time to change oils. That way you have no concerns on mixing oils that's not recommend.


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