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carb sync or good cleaning ... what do I need.

Discussion in 'XJ Technical Chat' started by blame_the_po, Apr 16, 2009.

  1. blame_the_po

    blame_the_po Member

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    trying to get 82 xj650 running after a while of sitting.

    What I did with carbs off
    clunk test - good
    general cleaning
    clean enrichment ckt
    rtv on rubber boots.

    Back together, what happens

    needs ether to start, but idles well when warm
    Throttle response good when pulled back slow, but huge hesitation when revved quick.
    test drive - tends to die when starting in first, but ok through other gears.

    I built my yics tool and u-tube manometer, should I get it idling, then sync? or do I have other probs to attack first >?
     
  2. johno8

    johno8 Member

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    Like my dad always says...If you want something done right, then don't rush it, and don't omit any steps. Since you're in the early stages of making it right, why not clean the carbs thoroughly, then put them on the bike and do the synchronization.
     
  3. blame_the_po

    blame_the_po Member

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    well thats what I thought I did. Everything looked good as a took it apart, so now im trying to figure out whats going on.
     
  4. johno8

    johno8 Member

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    Did you take the carbs apart and disassembled them to do a good cleaning? Did you have to replace any parts? How about adjusting the floats? These are all things that need to be done to ensure the carbs are not the issue. Just another thought, how about running some Sea Foam through them? Whatever is in Sea Foam seems to really help a lot of weird carb issues.
     
  5. blame_the_po

    blame_the_po Member

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    I took them apart, inspected and cleaned everything. it all looked pretty clean. Didn't replace anything. PO supposedly rebuilt them less than a year ago. anyway, what do you mean 'run seafoam through them' ? just soak them or ...
     
  6. JoeFriday77

    JoeFriday77 Member

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    Sounds like your carbs are not completely clean.

    Seafoam is an additive you add to your fuel and may help clean slightly clogged passages. You can give it a shot and see if it clears things up.

    If not, then you will have to pull the carbs and do a thorough cleaning.
     
  7. MN-Maxims

    MN-Maxims St. Paul Minnesota

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    Think twice about Sea Foam. Some of the guys here claim it eats the diaphrams. Turns the thin rubber to goo. Read up on that before you dump that in your tank.

    Lets start from scratch here.
    You should set the valves before any syncing is done.

    The carbs
    Did you look at the throttle shaft seals???
    There is a e-ring on the #4 carb facing outwards. Pop that clip off and remove the plastic washer. If that seal is rock hard you might as well get some ordered. Plan on splitting the rack. You can change all the fuel tube o-rings and give each carb a real good cleaning.
    You need to run thin wires through all the passages. Then blow with air and follow with carb cleaner and then air again. Any little peice of crud or dried gas will give you a headache.
    Check the little orfices in the well that the brass tube goes down into. The float bowl has a small hole that enters that well. Shove your red tube from the carb cleaner in there and hold it away from your face and give it a shot. It should squirt out about 10 ft.
    Check and set the float levels at the proper level.
    Replace the little o-rings on the mixture screws.
    Polish the brass emulsion tubes under the main jets.
    Take the enrichment plungers and polish those and make sure the rubber boots are not dryed out and they seal.
    If your carbs are clean and the valves are set and NO VACUUM LEAKS you can sync at that point. If you cut any corners you will not get positive results and you'll be pulling those carbs off several more times.
    Last but not least you have to have all the rubber boots in place air box to carb boots. The bike will not run right with out those in place since the jetting is calabrated from the factory to have those in place. Just a note if you have changed the exhaust or went to pods you need to rejet and that creates a whole different headache.
    The carbs on these bikes are the most tempermental things I have ever worked on. They need to be surgical clean and if you don't remember anything else when you read this. Your Syncing the engine to the carbs not the other way around. Hope this helps
     

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