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83 Seca 900 bogs down.

Discussion in 'XJ Technical Chat' started by MrSeca, May 17, 2020.

  1. MrSeca

    MrSeca Active Member

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    Thanks for responding. I'm still a little bit confused. What do you mean by the center of the float bowl and what is this picture explaining?
     
  2. MrSeca

    MrSeca Active Member

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    It seems to me and from the illustrations that I've seen that the fuel level in the tube should be equal with the bottom lip of the float bowl. NOT the top lip where the bowl meets the gasket but the bottom lip right where the screws are. If that's the case my Carb 1 is spot on but Carb 4 is off. Correct?
     
  3. Rooster53

    Rooster53 Well-Known Member Premium Member

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    The picture is from the FSM showing the method to wet check the fuel level of the carb on the bike. The general consensus is wet set needs to be done off the bike where the carbs can be leveled, however if you check them on the bike then the tube needs to be near the center of the bowl as depicted in the picture and not at the very back as you had done. It is also gets a bit more convoluted as the shape of the floats will affect the level of a tilted carb, so again why the consensus is off the bike with a level rack.

    If you need convincing then put some water in a clear glass and take a sharpie and mark the level at the center of the glass, then tilt the glass on axis with the mark and note how the level at the center does not change but moves up and down at the front and rear. You can also note with tilted carbs if you move the clear tube from back to front the level of the fuel in the tube will change going higher as the carbs are usually tilted down.
     
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  4. Polock

    Polock Well-Known Member

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    if the fuel level was low and leaning the mixture, the plugs wouldn't look like they do
     
  5. MrSeca

    MrSeca Active Member

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    Thank you for taking the time to explain that. Makes perfect sense.
     
  6. MrSeca

    MrSeca Active Member

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    With Hogfiddles help I think I found the possible culprit to my low mpg: worn emulsion tubes (see pic) I got rebuilt kits and installed brand new jets and tubes. I also spent an entire day working on the float heights (clear tube and height check) which were all over the place. I did not replace the slide needles though. When everything was said and done I clocked 100 miles at the halfway point which is a 25 mile improvement and 30 of those miles were city miles. I’m not complaining but not sure if The bike is working at it’s full potential yet. Throttle response is crisper though. I use to have a slight hesitation when I opened the throttle on the freeway possibly from running rich but that has pretty much disappeared. Also, I'm currently running heavier weight oil (20w-50) because of the hotter temperatures. Would this have an effect? What do you think?
     

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    Last edited: Jul 4, 2020
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  7. MrSeca

    MrSeca Active Member

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    So, I have to crack open my engine in order to fix the starter clutch. Never done anything like this before. For the most part there is never a problem starting the bike. It's usually after the bike is thoroughly warmed up and then I start it will the starter clutch start slipping. This happened the other day on a 7 hour journey where I pulled off for gas and after filling up the bike would not start. It just kept spinning and spinning. Luckily after the 7th attempt it started and I drove my ass home.
    I thought about buying a boroscope and dropping it in from where the starter motor connects to inspect. I'm kind of hoping that maybe there's just enough sludge built up somewhere and that if I can spray some sort of cleaning solvent (SeaFoam) I can remedy the situation. But I think this is wishful thinking. I have already tried throwing SeaFoam in with the oil and running it for about 15minutes then drain. I've also tried thicker oil 20w-50 and that didn't help. I tried servicing the starter motor and also using the starter motor from my 650. Nothing worked. Gotta go in. Any words of advice before I kill the bike I love?
     
  8. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Send the 900 to me:D:D:D:D:D
     
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  9. Franz

    Franz Well-Known Member

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  10. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Spraying carb cleaner toward the starter clutch will clean out any crud. Make sure that the starter motor brushes are in spec, and that the motor is free of exessive carbon dust. The battery should be load tested as well. Do all of that BEFORE splitting the cases.


    FWIW...they aren't so bad to push start, so parking upslope could save you a lot of work.
     
  11. MrSeca

    MrSeca Active Member

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    Already tried everything you said. And I live in a flat neighborhood.
     
  12. MrSeca

    MrSeca Active Member

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    On a different note the float height on carbs 2,3, 4 are like the 1st pic. The float height on the 1 carb is like the second pic. Is this an issue?
     

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  13. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Yes. Assuming that you set the bike so the carbs are level 2, 3, and 4 are low. Out of spec low.
    Setting the fuel levels
     
  14. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    I just took the time to read this whole thread. Starting with "he (PO) barely rode the bike for the last 15 years" and amongst all of the discussions of various dragons being conquered and new ones popping up, a lot of riding, etc., nowhere do I see any mention of rebuilding the brakes. Most importantly, brake LINES since they are all hydraulic, but calipers and master cylinders as well. The rear M/C has a remote reservoir, be sure to inspect that small hose as well. Hopefully you have already replaced the 37 year old brake fluid at both ends and bled everything.
     
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  15. MrSeca

    MrSeca Active Member

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    Thank you Bigfitz for reviewing this post. You are correct, I have yet to change out the brake lines and it is on my list of things to do with this bike. I did, however, refurbish the calipers and they are working brilliantly.
     
  16. MrSeca

    MrSeca Active Member

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    I did not set the bike which is, I assume, raising the front tire just enough so that the carbs are level? I was under the idea that if the tube is positioned at the middle of the carb body the fuel level reading in the tube will be more or less correct.
     
  17. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Yes, it should be close enough to get a good idea about the float levels. If you were reading in the middle of the bowls my assessment is still correct.
     
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  18. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    eehhhh... the FSM's suggestion about checking float levels ON the bike depends on the bike being level side to side, and reasonably so fore and aft. And is hard to get accurate readings with.

    The only way you're gonna get accurate "wet" readings on all 4 carbs is with the rack off the bike. And if the goal is perfection, no "+/-" anything, spot on, all exactly the same; the only way to achieve it is with the rack off the bike so fine adjustments can be made.
     
  19. MrSeca

    MrSeca Active Member

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    Why are one of my carburetors leaking out of the overflow tube only when the bike is in operation and the petcock is set in the ON position but doesn't leak when parked and the petcock is set to PRI?
     
    Last edited: Oct 5, 2020
  20. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Things to check-could be:

    Too much fuel in the carb.... float level too low, or float could be stuck down

    valve out of spec causing blowback

    at least you know the petcock is working correctly!!!
     
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