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Running rough, did bench sync

Discussion in 'XJ Technical Chat' started by mattzmojo, Jul 30, 2008.

  1. mattzmojo

    mattzmojo New Member

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    My 650 is running rough, it has problems seeking and staying running in idle with out turning the idle adjustement up.

    What have I done?

    1-checked compression. pretty good- one cylinder seemed a bit low..but..ok.
    2-cleaned carbs. was not bad but I cleaned the heck out of everything.
    3-bench synced carbs as best as I could.

    Now I think I am ready to do a true syncronizaion......
    Questions:

    1-Has anyone had success building the YICS tool? I downloaded plans and instructions.......but I dont know where to get the rubber material that will not melt or breakdown under the heat and running conditions.

    2-Does anyone have a picture of where the YICS is inserted?

    3-Do I have to prop my gas tank up somehow and use a longer length of fuel line hose?

    4-ONce inserted and tightened Can some one show me a picture of exactly what screws need to be turned?

    Any help is appreciated.

    I feel dumb and intimidated by this stuff............ I am an Air Conditioning tech and I can fix the hell out of anything on in or under a house but this stuff is unchartered territory.

    :) 8O
     
  2. bill

    bill Active Member

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    Bench sync how to with pictures

    http://xjbikes.com/Forums/viewtopic/t=6 ... +sync.html

    You would adjust the same screws you used for bench sync.

    I purchased a tool cause I didn't want to run around town finding the right tubing and chancing having the wrong tubing.

    I remove my tank - much easier to to get to the screws and vacuum ports. I made an aux gas tank to run the bike.

    I don't have a picture but above the carbs on the head you should see a 12mm bolt head on each side of engine. That's the YICS port.
     
  3. mattzmojo

    mattzmojo New Member

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    Thanks Bill! I will probably purchase one too.
     
  4. turtlejoint

    turtlejoint Member

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    yeah i would too. i got the wrong tubing and melted my YICS tool. was a total pain to get out and clean.
     
  5. bill

    bill Active Member

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    Chacal has them for $37 hopefully mine arrived today...
     
  6. Polock

    Polock Well-Known Member

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    i'am going to catch all kinds of hell for this but sync them without the yics tool
    then if you feel the need to, get the tool and do it again
    i've done it both ways and kind of like the results without it
     
  7. mattzmojo

    mattzmojo New Member

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    Are you talking about syncing them on the bench? Or trying to blindly make adjustments while running?

    Thanks,
     
  8. bill

    bill Active Member

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    He is referring to doing the sync on the bike without the YICS ports being blocked. There has been some debate you can read through. I'm not qualified to comment on which is correct.

    Debate is do you sync under running conditions vs using the YICS tool. Common wisdom is that without the ports blocked by the tool (isolating the carbs) you can't get a good sync since you are measuring vacuum and the port allows carbs to share vacuum. I'm gonna go with the tool because I'm not sure which is right and I'll err on the side of what the factory recommended by using the tool.
     
  9. mattzmojo

    mattzmojo New Member

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    After LOoking at my Motor I do not see either a YICS label or the 12mm screw where the YICS tool goes.

    I have a 1981 Yamaha Maxim. I was under the impression the 81 is a Yics i BELIEVE I dont have a YICS.
     
  10. bill

    bill Active Member

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    You don't have YICS - so makes it easier. Stealing from Chacal's post and his wealth of knowledge:

    YICS was used on all XJ550 models, 1982-up XJ650 Maxim and XJ650 Turbo models, all XJ700 non-X models, all XJ750 models, 1983 XJ900RK, and 1982 XJ1100 models. The 1980-81 XJ650 Maxim and 650 Midnight Maxim models, as well as the 1982 XJ650 Seca models, did NOT use the YICS system. It has also been reported by some owners that some very early model 1982 XJ650 Maxim models did not use the YICS system.

    YICS bikes have front lower (oil pump) covers on both sides that have a rectangular "YICS" emblem in them below the cast-in YAMAHA wording. Non-YICS models have the oil pump covers with only the YAMAHA wording cast into the cover.

    YICS bike also use a valve cover that has the word YICS cast into the top surface, while non-YICS models are blank or are cast "YAMAHA" (or "YAMAHA 5VALVE on 700-X/750-X models) on the valve cover.
     
  11. Ass.Fault

    Ass.Fault Active Member

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    No yics, no problem.
    If you do have yics, anybody can make a tool!
    I take strips of cut up cotton shirt.
    Tie them together,
    Soak in Marvel Mystery Oil,
    and insert with a dowel.

    Quite cheap and avalible at the local store.
    AND it also cleans the passage, which does need to be done after 25 years.

    A link to the HOW TO SYNC THREAD

    http://www.xjbikes.com/Forums/viewtopic/t=2132.html
     
  12. bill

    bill Active Member

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    Fault - I did that twice - a royal pain so I ordered a tool. But your right it cleans the passage well.
     

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