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bad acceleration and bogging down

Discussion in 'XJ Technical Chat' started by jmilliken, Apr 14, 2013.

  1. jmilliken

    jmilliken Well-Known Member

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    I have been having some tuning issues on my bike and it's gotten much better, but still not right.

    To start out at the beginning. The bike originally had pods and a very lean condition. swapped to the airbox. Compression is in the 140's across all 4. Shims are good, carbs are spotless, bench synced, and everything is in good condition. Then i started having issues fouling plugs and running very poorly. I found my floats were off and i was dumping a little bit of fuel into the engine + crankcase as i was running. Reset the floats and it seems to have fixed itself. no more fouling plugs etc. and seemed to run decent.

    Recently upgraded to dyna coils. Switched from resistor caps/non resistor plugs to non resistor caps/resistor plugs on advice from Len. Finally got some other stuff streightened out and was able to ride it around town on a test ride today. HORRIBLE!!!!!!

    I couldn't get it over maybe 30 mph 5000 rpm, or so. it lagged, stutterred, stalled when pulling out, and generally was not running like it should. I'm stumped. Pulled the plugs and 1,3,4 were sooty black. Kinda getting irritated with this bike at the moment.....
     
  2. Kwiski

    Kwiski Member

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    I had a coil go bad(cracked) that was on the 900 motor I switched from 650 to 900. I thought I would have problems with the 650 coils as they are different numbers. But using them & the 900 pick-up coil on crank. This bike still hits 9500 RPM all day & runs great. First go back on what you did last to see if problem corrects itself. If that is not it you may still have carb issues.
     
  3. jmilliken

    jmilliken Well-Known Member

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    pick up coil on crank or ignition coil was cracked?
     
  4. hogfiddles

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

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    Things that come to mind...in no particular order---

    Check the ends of the plug wires.....you may need to snip them back a 1/4" or so and reattach the wire ends.

    or

    The TCI is going bad

    or

    are the jets the correct jets for the stock configuration

    or

    drain the tank and dry it out to make sure that there is NO water in there that can get sucked up into the fuel line.

    Whatever the case.....don't get discouraged. It's a temporary setback. We just have to trouble-shout it until we get it.

    Dave F
     
  5. pjk_xj700

    pjk_xj700 Member

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    How old is the gas? how long has it been sitting with same gas? ethanol? I know ethanol evaporates quicker, so can leave crap in your carb sooner than non e-gas.

    I've had slugs of water a few times in my bikes in the past and it did just the same: stuttery, sputtery, missing, etc.

    I've had a few cars get same problem.

    A shot of dry-gas usually fixed her up. Don't put whole thing in the tank though, just a quarter or less, I'd guess.
     
  6. jmilliken

    jmilliken Well-Known Member

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    Plugs + wires are brand new

    I'll swap out the gas. It's old. Talked for a bit to Rick last night.... My jetting is stock numbers, but based on our conversation, it sounds like my jets could have potentially been tampered with. He explained how to measure the jets with drill bits.
     
  7. mlew

    mlew Well-Known Member

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    Was the carb jetting changed at some time? Maybe the PO tried to re-jet for the POD filters. I would start by making sure the main and pilot jets are the correct size. Don't just go by the number on the jet, measure it. I have found that their are many people who do try to drill jets out and screw then up.
     
  8. Polock

    Polock Well-Known Member

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    choke shutting all the way off?
     
  9. BruceB

    BruceB Active Member

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    Just throwing this out as I am not as experienced as most on this form, but is sort of sounds like a kinked ( or clogged) fuel line. Idles great but starves for gas under demand.
     
  10. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Fuel levels too high or still/again leaking?

    Gas cap venting properly (does it run any better with the gas cap left un-latched)?

    Plug wires going to the correct cylinders?

    NOTE:

    * on the primary side of the coils, the proper colored leads from the TCI must be hooked up to the proper coil......see below. However, it does not matter which of these two wires go to either position on the coils.

    - the ignition coil for the #1/#4 spark plugs is mounted on the left side of the bike, and has the solid orange (ground) wire and the red-with-white-tracer-stripe (hot) wire input leading to it.

    - the ignition coil for the #2/#3 spark plugs is mounted on the right side of the bike, and has the solid grey (ground) wire and the red-with-white-tracer-stripe (hot) wire input leading to it.

    - thus, for the #1/#4 coil, you must use the wiring lead from the main harness (TCI) that has the has the solid orange (ground) wire and the red-with-white-tracer-stripe (hot) wires, as these wires carry the timing trigger pulse to fire the #1/#4 plugs. However, it does not matter whether the orange wire is installed to the top input terminal of the #1/#4 coil, or to its bottom input terminal. In other words, there is no "polarity" to a coil's primary circuit.

    - also, on the secondary (output, spark plug lead wires) it also does not matter which plug wire goes to which cylinder (because they actually both fire at the same time). Thus, for the #1/#4 coil, you can hook either plug wire lead to the #1 or the #4 cylinder.
     
  11. waldo

    waldo Member

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    This is one I found on a bike hard to see check it closely.
     
  12. jmilliken

    jmilliken Well-Known Member

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    Ok. Here's an update...... swapped TCI with known good spare - no change, checked all the obvious bits (gas cap, fuel lines, vacuum lines, plugs etc etc) - no change, new fuel -lines no change popped the carb boots off the airbox - SLIGHT IMPROVEMENT. Runs like poor, can't get over 5500 rpm or so.... and backfires like the pipes are going to blow apart. Plugs are CHARCOAL SOOTY black..... gonna pull the rack here in a sec
     
  13. jmilliken

    jmilliken Well-Known Member

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    How about my main fuel jets are 36.5 and my pilot jets are 107.....




    OOPS......
     
  14. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Could be cause for concern................. :D
     
  15. waldo

    waldo Member

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    you wont be the first to put the jets in the wrong spot damhikt
     
  16. jmilliken

    jmilliken Well-Known Member

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    Lol.... at least I can laugh over my 6 months of frustration.... ill work on it tomorrow. My son wants me to play skylanders with hin
     
  17. waldo

    waldo Member

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    skylanders? Say what?
     
  18. jmilliken

    jmilliken Well-Known Member

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  19. waldo

    waldo Member

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    My youngest is 29 so I have been out of the video games for a while now I do remember playing Zelda on the nintendo enjoy it while you can, time truly does pass faster and faster
     
  20. jmilliken

    jmilliken Well-Known Member

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    OK... I hate unresolved posts.... so I put the main + pilot fuel jets in the right location.... and we're good!
     
    First82maxim likes this.

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