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  1. #1

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    Still smoking after carb adjustment

    I'm experiencing way too much smoke out of the back of my xl1200 limited. It's a 2000 with powervalves. I've been given great advice on the forums here but can't seem to pinpoint my machine's problem. It runs perfectly at top end, but not very smoothly at idle and loads up with smoke. I turned my low adjusters to 3/4 out, which helped a bit. My 3rd cylinder is reading 110, the other two at 120. My question is, can I get that third cylinder out to take a look at it without pulling the manifold off? It's an SBT top end kit and I'm wondering if the cylinder isn't great. Can I put OEM rings on an SBT cylinder. Will new rings even help? I rebuilt the carbs, but it's definitely flooding out when it sits (with the gas on). When I shut the gas off before I stop it, the engine fires to life with just a touch of the starter. Why might it be loading up? Could I have missed something with the carb rebuild? Any and all advice welcome.


  2. #2
    TX21's Avatar
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    Oem rings will not work on sbt pistons. have you downloaded the service book that explains all the ring gap, cyliner tolerances yet?

  3. #3
    mudslanger's Avatar
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    It sounds like you need to go back through the carbs. and make sure they are not leaking by the needle seat or the seat Oring. they should hold pressure without leaking down before the needle pops off the seat.

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  5. #4
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    +1 needles and seats for sure.

    Hydrolocking with fuel is one step below walking into a fireworks factor smoking a cigar.. While your looking into this..check to make sure the tank check valves are working properly too..a stuck check valve can let so much pressure build up that a marginal needle will let the engine flood with fuel. Relative speaking, the are so cheap I repalce them on ever job lately. With high desert temps it's all too often I get a call for a "no start" that turns out to be an engine full of fuel

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  7. #5
    This is what i saw in mine this weekend. I took a look inside the engine bay and I had a lot of black marks of oil towards the PTO. I was not able to see it good and I also had 110 compression in the PTo cyl. I took out the engine and after closer examination I realized that I had a leak on the bottom of the crankcase.I took out the motor mounts and the bottom of the crank and found a lot of oil in the base of the crank and also a lek in the seal. Actually is not a seal or a gascket per say it is a liquid seal that they make when they assamble the engine. I cleaned everything up. Use a better seal and the smoke is gone!

    NOW!!! Before you pull the engine look for the signs that it might be the same problem. Look at the spark plug. If it is a bit leaner than the other 2 then you might have that problem. also if you see the oil stain inside the hull towards the PTO then you might have the problem. you already have the smoke so you have one out of three.

    I hope this helps

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  9. #6

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    Quote Originally Posted by ccameselle View Post
    This is what i saw in mine this weekend. I took a look inside the engine bay and I had a lot of black marks of oil towards the PTO. I was not able to see it good and I also had 110 compression in the PTo cyl. I took out the engine and after closer examination I realized that I had a leak on the bottom of the crankcase.I took out the motor mounts and the bottom of the crank and found a lot of oil in the base of the crank and also a lek in the seal. Actually is not a seal or a gascket per say it is a liquid seal that they make when they assamble the engine. I cleaned everything up. Use a better seal and the smoke is gone!

    NOW!!! Before you pull the engine look for the signs that it might be the same problem. Look at the spark plug. If it is a bit leaner than the other 2 then you might have that problem. also if you see the oil stain inside the hull towards the PTO then you might have the problem. you already have the smoke so you have one out of three.

    I hope this helps
    I have the feeling this is really going to help. I am running leaner on that pto cylinder, but I haven't noticed any oil stains on the hull near the pto. Did your machine smoke like crazy at idle? How was the idle before you fixed it, smooth or a little 'lumpy'? Also, when you say you used a better seal, what product are you talking about? Thanks again for your help!

  10. #7

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    Quote Originally Posted by nmpeter View Post
    +1 needles and seats for sure.

    Hydrolocking with fuel is one step below walking into a fireworks factor smoking a cigar.. While your looking into this..check to make sure the tank check valves are working properly too..a stuck check valve can let so much pressure build up that a marginal needle will let the engine flood with fuel. Relative speaking, the are so cheap I repalce them on ever job lately. With high desert temps it's all too often I get a call for a "no start" that turns out to be an engine full of fuel
    Thanks for the info! Where are the tank check valves and how do you test them? Are they up near the tank itself or down by the carbs?

  11. #8

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    Quote Originally Posted by mudslanger View Post
    It sounds like you need to go back through the carbs. and make sure they are not leaking by the needle seat or the seat Oring. they should hold pressure without leaking down before the needle pops off the seat.
    I'm pulling the carbs off, doing a pop off test and I'll let you know what I find. Thanks!

  12. #9

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    Quote Originally Posted by TX21 View Post
    Oem rings will not work on sbt pistons. have you downloaded the service book that explains all the ring gap, cyliner tolerances yet?
    I have the service book and see the procedure for testing the end gap clearance. I'm ordering new rings from SBT and making sure they're correct before reassembly. Hope this works.

  13. #10

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    Rings are not going to fix a smoke problem, especially since the boat runs great on top end. You would be better off looking at the carbs again like mentioned above. 110 psi compression is within the bottom area of normal limits. If you have a primer may want to be sure it is not leaking thru with tank pressure.

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