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Gunson Colortune Issues

Discussion in 'XJ Technical Chat' started by Mjolnir, Apr 18, 2020.

  1. Mjolnir

    Mjolnir Member

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    I double checked the fuel levels and they were all dead on except 4 which I adjusted to proper spec (1MM +/-1MM) I’ll post a pic of what it was and you can tell me if it’s off.

    I posted the jet sizes earlier and they are all basically brand new.
     

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  2. Mjolnir

    Mjolnir Member

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    I removed the airfilter and within a little bit it was running better and smoother. Took her for a ride and super responsive, just wanted to run like it’s supposed to. Ive attached a pic of my air filter which got flooded with gas a few times due to the leaky petcock. Would this dirty filter make that much difference? And how bad is it to run it without the filter?
     

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  3. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    It's hard to tell from the picture, since it wasn't taken "level" with the fluid at the top of the tube, but, it still looks like it is too low......it's should be 1mm +/- 1mm front the base of the carb body, and it's the "dip" in the fluid that is the measurment point (fluids "ride up" on the sides of a tube, and the risen sides are not the actual fluid level, it's the bottom (base) of the "U" shape that the fluid makes which is the real fluid level in the bowl (and thus the reference point for measuring).

    Make sure you check your AIR JETS (under the rubber vac piston diaphragm) to make sure they are placed correctly (the Haynes manual has the jets reversed in their picture),,,,,,the PILOT air jet (in the forward position) is the larger of the two, the MAIN air jet (center hole) is the smaller of the two.
     
  4. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    That filter isn't all that dirty, but if it got fuel-soaked it's not passing air properly (the paper turned to mush, blocking the pores) . Restricted airflow = richeens up the fuel mixture.


    Terrible idea, you'll wear out the rings in a few thousand miles or so (depending how dirty/dusty/gritty the air is around you).
     
  5. Mjolnir

    Mjolnir Member

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    I haven’t taken apart the top of the carbs since they were rebuilt by hogfiddles so I’m pretty sure he didn’t switch them, but I could check just to be sure.

    That makes sense about the filter. Looks like I’ll probably be ordering one then
     
  6. hogfiddles

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

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    I doubt I mixed them up. But check anyway. Sounds like your air filter needs to be replaced..... did you ever install the snorkel? I recall that was missing but I don’t recall if I sent it to you Or if I put it in here....
     
  7. Mjolnir

    Mjolnir Member

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    Yup the snorkel is in place. I’ll probably get a new filter then and see what it does from there. It shouldn’t flood anymore with the on/off shutoff so I won’t have to replace it for a while.
     
  8. Mjolnir

    Mjolnir Member

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    How much will the octane rating in the fuel effect how the bikes runs/behaves? I was told by someone to run high test in it, but I saw somewhere that hogfiddles runs 87 octane with no problem. Will that throw off my tune at all?
     
  9. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    It shouldn't.........octane ratings are (basically) a measure of resistance to detonation (pre-ignition, a/k/a engine pinging or knock), it's the ability of the fuel to not self-ignite due to high combustion temps caused by high-compression ratios (and other factors) of some engines. XJ engines aren't all that of high-compression (about 9.2-to-1 or thereabouts) and don't really benefit from higher octanes, but it won't hurt anything (besides your wallet)......
     
  10. hogfiddles

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

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    I run 87 in all my bikes.
     
  11. Mjolnir

    Mjolnir Member

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    Okay, ordered an air filter, but my bike didn't come with horns...I ordered some last year off eBay that look in great shape, but they won't sound. Any suggestions to check them or the wiring on the bike to make sure I have power? The horn wires are on the bike, but someone removed them for some stupid reason.
     
  12. hogfiddles

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

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    Hook the horn up to a battery wit one wire, the momentarily touch the otherwise to the terminal. You’ll know either way very quickly. Then try the other. If either is good, hook it back up on the bike
     
  13. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Hook the horns up directly to the battery (use some short runs of jumper wires, etc.) ....either terminal on the horn can be either positive (or negative). If they don't work hooked directly to the battery, well........

    Whoops, quick-draw Fiddles beat me to it!
     
  14. Mjolnir

    Mjolnir Member

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    Okay, that's what I thought so I tried it over the weekend and neither horn works. Thanks for confirming my suspicions though!
     
  15. Mjolnir

    Mjolnir Member

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    Alrighty, so I have the new airfilter in (thanks chacal!) and been playing with the idle mix and then carb synch. I normally ride around 30-40 mins but took it for an hour 15min ride (longest yet) and it ran great at first but as the bike got hotter and hotter it ran worse and worse. It wanted to die at idle without the throttle held on and lacked power overall. I almost didn't make it back! I'll post pics of the plugs, but I still can't get the Colortune to work. Most of the screws can go all the way in or out and it doesn't change the color away from bunsen blue.

    Another weird thing...after this latest adjustment after the bike warms up it wants to rev and stay high, but if I apply either brake...the idle will drop back down to where it's supposed to be...what's up with that?!?! It's been an issue before, but that was before the latest round of new parts and repairs.
     
  16. Mjolnir

    Mjolnir Member

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    6AC465FF-9E5E-4C7E-A656-5585D3202F67.jpeg 4FF70D68-B885-4E8E-9924-D796FBE073AC.jpeg 86F56680-81BC-45CA-938C-A4A7BDF7779D.jpeg
    Pics are of C2-3-4 in that order. I forgot to get a pic of C1.
     
  17. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    The pilot fuel circuit is clogged for some reason.........either the jet, or internally, or the o-ring is missing/damaged in the mixture screw bore.
     
  18. Mjolnir

    Mjolnir Member

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    I know I cleaned the pilot fuel circuit and jet (that's the one in the side of the bowl that everyone misses the first time correct?), but the o-ring could very well be the issue. I just unscrew it all the way out to check correct? Anything I can do to test that?
     
  19. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    No, the small passage thru the BOWL is part of the starter (choke) system (the brass tube that drops down from the bottom of the carb body fits into that passage in the bowl, and is also part of the choke system). The pilot fuel circuit jet is one of the two (the smaller of the two) brass jets screwed into the bottom of the carb body., and it leads eventually to the passage that the pilot mixture screw controls:

    http://www.xj4ever.com/inside your carbs.pdf

    Yes, you can unscrew the mixture screws all the way and there is (in this order) a spring, a flat washer, and at the bottom of this crackerjack box is the o-ring.
     
  20. Mjolnir

    Mjolnir Member

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    Ah, okay, I'll screw it and see what happens. If I add the slightest amount of enricher it does race away so it's definitely slightly lean. I'll have a look see but I'll probably end up ordering something from you in the near future :D
     

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