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1982 XJ1100 Maxim Gas mileage is horrible.

Discussion in 'XJ Technical Chat' started by ShootyMcBang, Mar 1, 2020.

  1. ShootyMcBang

    ShootyMcBang New Member

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    I recently acquired a 1982 XJ1100 Maxim. I have run two tanks full of fuel through it and it averaged less than 22 MPG. Are there any XJ1100 Maxim owners than can speak as to what their bikes are getting for mileage? I run 91 octane. There are no obvious issues with the bike that I can tell. No leaks. The motor purrs. The throttle response is perfect in my opinion. (Which may be an issue as fa as needing to take it easy on the throttle I am just curious what others are getting. Thanks.
     
  2. Timbox

    Timbox Well-Known Member

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    You might want to take a look at the oil window. If it is full to the top, take the cap off and take a sniff, if it smells like gas you might have found one issue. You just picked up the bike so have you don't any maintenance on it? Most times these bikes have carb issues if they have been sitting longer then a yr. If the float bowls are off gas will leak into the engine.

    This if the petcock is on prime and not on "on" or "res", and the petcock is working correctly. If there is gas in the oil it needs to be changer right away. Thinning the oil and running the bike is not good for the bearings and will have bad lasting effects.
     
  3. mlew

    mlew Well-Known Member

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    I average 30mpg with mine. A little over 40mpg on the highway. Depending on the traffic conditions I have seen 25 in stop and go
     
  4. JetmechMarty

    JetmechMarty Active Member

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    I just went through this. My XS1100 was getting 24 mpg. I replaced the needle jets (emulsion tubes) and the jet needles sourced from a lower mileage set of carburetors. Now, I'm averaging about 40 mpg. XJ4ever.com has replacements.

    Make sure your ignition advance is functioning properly.
     
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  5. lostboy

    lostboy Well-Known Member

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    Check the air filter.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    XS11 reports 32 to 48 as an avrage mpg
     
  7. Timbox

    Timbox Well-Known Member

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    I know my XS1100 had this issue, the light blue wire was broken inside the insulation, it is a common issue. Does yours have the vacuum and mechanical advance on your bike. Mine has both, and as the wires do the hard bend coming off the pickup plate. The bike will seem to run correctly but it really is not. Easy fix.

    Here is what I did to fix mine. It is about half way down the page with pics.
    https://www.xjbikes.com/forums/threads/1979-xs1100-not-a-xj900-but-it-will-do-for-now.123974/page-5
     
  8. JetmechMarty

    JetmechMarty Active Member

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    The XJ1100 got electronic advance, and in turn, eliminated those issues.
     
  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    shooiy can you post the pin out of your tci? someone here needs to see it
     
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  10. tabaka45

    tabaka45 Well-Known Member

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    Check your voltage. Mine was low and when I replaced the brushes, voltage went up to normal and mpg went up a lot--probably 4-5 mpg or more.
     
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  11. JetmechMarty

    JetmechMarty Active Member

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    Yes, check it at the coils. Corrosion in the connections can cause voltage drops.
     
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  12. ShootyMcBang

    ShootyMcBang New Member

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    I I will post a picture of it. I went out to look at it, there are two PINs going into the module which were wrapped with electrical tape. When I took the tape off the plastic molding that actually houses the connections crumbled like sand in my hands. I will take a pic and post it.
     
  13. ShootyMcBang

    ShootyMcBang New Member

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    Thanks for the responses to my questions. It looks like there are a couple things I can do to possibly makes some improvement.
     
  14. ShootyMcBang

    ShootyMcBang New Member

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    ..........I'll be looking into my wiring as it seems to be sketchy in a few places.
     
  15. ShootyMcBang

    ShootyMcBang New Member

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    Good advice. I did change the oil when I first brought it home. (200 miles ago)
    There was a full pint too much oil in the crankcase when I got it. There was no fuel in the oil. the petcocks are working as they should at this point.
     
  16. ShootyMcBang

    ShootyMcBang New Member

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    P1010003 (35).JPG
     
  17. ShootyMcBang

    ShootyMcBang New Member

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    What I will do is actually hand write the wire color and the corresponding "slot" it is assigned to. That may be more accurate than what this picture shows Apparently I'm going to be doing some wire work as well.
     
  18. Timbox

    Timbox Well-Known Member

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    If that is mouse/rodent damage, there might be more wires that have been chewed on. That could have been from the seat or something rubbing on the plastic but looks to be chewed. Those lose wires look good and as long as they are still secure in the connector you should be good. If you plan on rewiring that plug just make sure that it will plug back into the unit and made a good connection.

    I would made sure that the wires are still secure in the plastic connector. If they are still held in place just put some liquid tape in those chew holes. Again look around the rest of the bike for obvious signs of chew damage. It might be a good idea at the same time check each connector for corrosion. Using a small flat head screw driver to scrape off the corrosion and then add some dielectric grease on them.

    Good luck and keep us posted.
     
  19. JetmechMarty

    JetmechMarty Active Member

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  20. ShootyMcBang

    ShootyMcBang New Member

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    I got the bike out of San Jose, CA and I think the salt air may have eaten it up. The plugs seem to be married to the TDI and the connections looked to be good and firm. I took a hot glue gun and filled it in nicely to keep it somewhat safe.
    It does appear to have been chewed but actually what isn't in the picture is the debris from the crumbled plastic that stuck to the electrical tape when I unwrapped it.
    Okay I checked, doubled checked and triple checked the location of the wires onto the plug end: Going by the picture:

    on the 8 pin plug going left to right The top row I numbered 1-2-3-4. The bottom row I numbered 5-6-7-8
    #1 grey wire
    #2 black w/red stripe
    #3 black w/white stripe
    #4 black w/yellow stripe
    #5 orange
    #6 NO WIRE
    #7 red w/white stripe
    #8 black

    On the 4 pin plug going left to right The top row is 1-2. The bottom row is 3-4.

    #1 NO WIRE
    #2 grey
    #3 black
    #4 orange
    Hopefully this will help.
     

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