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1985 maxuim 750x

Discussion in 'XJ Technical Chat' started by malibuman, Oct 28, 2010.

  1. malibuman

    malibuman New Member

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    I have a 1985 maxium 750x (watercooled) It needs all the valves replaced which is way to expensive....So I need a used cylinderhead or..........

    Just got offered a 1983 maxuim x (air cooled) which has been vandalized


    Are these bikes really different? I haven't seen the 83 yet
     
    malibuman, Oct 28, 2010
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  2. bkerby

    bkerby Member

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    Different motor, the 83 is not an x as they were made only in 85-86. Big difference in horsepower. I dont know the particulars on difference in phisical size of the motors or if the 83 will bolt in or not but u can bet your rumpkiss someone on here does.
     
    bkerby, Oct 28, 2010
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  3. Desinger_Mike

    Desinger_Mike Member

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    Why do you think it needs all the valves replaced?
    They could simply be out of adjustment....or if they were out of adjustment and still run may just need to be resurfaced?

    There are a number of heads on Ebay, but I would still plan on changing stem seals (if your budget permits) or at least lapping the valves to ensure you have a good seal.
    Regardless you will need to adjust them once you get them on the bike. It's a time consuming project that CAN be expensive (if you need to buy 20 new shims @ $10 each)...plus you'll need a head gasket and should do the valve cover gasket while you are at it.

    Some of us have a bunch of spare shims laying around to swap to save you some coin.
     
    Desinger_Mike, Oct 30, 2010
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  4. malibuman

    malibuman New Member

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    the valves are so bad lapping won't work they have a major wear....
     
    malibuman, Oct 30, 2010
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  5. Desinger_Mike

    Desinger_Mike Member

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    It's very odd to see these valves showing wear.
    Mostly likely the cause of neglect and never adjusting them.
    IF they are indead killed, the rest of the engine would be suspect

    There are a bunch of parts/complete engines on Ebay but a lot of the sellers are INSANE with their pricing.
    This one might be a candidate. http://cgi.ebay.com/ebaymotors/85-xj700 ... ccessories

    Post some pics. A machine shop can do wonders. Usually the engine won't run at all when they get to the point they need grinding.
     
    Desinger_Mike, Oct 30, 2010
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  6. theadbrewer

    theadbrewer Member

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    I was thinking the X was the Genesis motor which is a 5 valve the 83 would be a 2 valve per cylinder so they are totally different. Also air vs. water cooled.
     
    theadbrewer, Oct 30, 2010
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  7. waldo

    waldo Member

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    How many miles on this bike? What makes you think the valves are that bad to begin with? Has to be a head from another X water cool to swap in. What about the guides.
     
    waldo, Oct 30, 2010
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  8. apsolus

    apsolus Member

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    once i was lied to about my valves, they said i had to replace my head. i did a valve adjustment and all was dandy. i hate a liar
     
    apsolus, Oct 30, 2010
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  9. schooter

    schooter Active Member

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    finding another engine or doner bike would be the best bet.... though an aircooled 85 and 86 may drop in, even though i had an 85 700 im not sure
     
    schooter, Oct 30, 2010
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  10. malibuman

    malibuman New Member

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    The owner of the bike (friend of mine) never did any maintenace on it the valves really needed to be ajusted....everybody told him that.
    One day he phoned me and told me it died....so I brought it over to my shop and did a compression test.two cylinders no pressure then I did a leak down test air was escaping out the carbs.Pulled the head off

    The valves are concave at the seat....
    95000 km

    The friend of mine really has no ambition to take care of the things he owns he has wecked every thing he has owned though neglect.

    the only reason I took on the bike is it was the 1st bike I have ever ridden and got me hooked.
     
    malibuman, Oct 31, 2010
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  11. Desinger_Mike

    Desinger_Mike Member

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    The valves should still be easily ground (I would think)

    While they are grinding them, they can shorten the stem so the shims you have will give you proper clearance....it just takes some time really.

    I have a spare "loaded" head (or three) but reworking what you have would be a better option IMO

    Make an offer to some of the Ebay sellers and see if someone bites at a lower offer. They can only say NO
     
    Desinger_Mike, Oct 31, 2010
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