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Another '82 XJ750 Maxim - anyone got a spare head?

Discussion in 'Hangout Lounge' started by Ted, Sep 3, 2014.

  1. Ted

    Ted Member

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    First of all, some of you might remember that I picked up a pair of non-XJ's about 6 months back (http://xjbikes.com/Forums/viewtopic/t=45456.html). Well those sat around for a few months and got in the way. I lost interest and sold them for exactly what I had into them.

    Soooo I Picked up another '82 Maxim XJ750 last night off CL. Paid $350 cash and rode it a little more than 20 miles back to my house. :D

    The PO said he paid a shop over $500 bucks 2 years ago to service the carbs but the thing wouldn't idle when I got there. He said you have to find a "sweet spot" for the choke to get it to run and he's never been able to get it to run with the choke all the way off. I spun the idle knob out a couple of turns and voila - purred like a kitten. He was amazed. :lol:

    The bad - has a starter issue, which is one of the few things I haven't had to touch yet on my other bike. It will just spin the starter and not crank sometimes & the PO said it usually only does it when the bike is hot... I'll post a question on that in the Chat section.

    The worse - somebody garbled up the exhaust studs and busted off the lower threads on #4 so it's got a leak right at the port. I might check into having a shop weld a new ear on there that I can puts some threads in but might end up doing a head swap.. any thoughts?
     

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  2. Ted

    Ted Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    Short to-do list:

    1. Check Valve clearances
    2. Oil & filter
    3. Resolve starter issue
    4. Fix exhuast leaks
    6. Get rid of the god-awful paint job

    Probably gonna' end up as a bobber similar to my other one for the wife to ride... might try to go for a 2-up version similar to this:

    http://xjbikes.com/Forums/viewtopic/t=45304.html
     
  3. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    WHO knows what the PO has in it for oil.

    A simple oil and filter change might fix your "starter" issue.
     
  4. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    Head swap in your future..............
     
  5. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    ]

    Unless he gets friendly with a decent machinist who can weld.

    Find someone who is close to retirement, and appreciates a good scotch. Lots of expensive repair work can get done for a reasonable cost if you use the right form of payment. A trade school is also a good choice. The worst they will do is ruin an already damaged head.
     
  6. hogfiddles

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

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    Re: Scored another XJ last night - any NY Giants fans out there?

    You're gonna be doing aluminum welding there, which is a little bit different from steel welding.....................

    dave
     
  7. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    Yes it is. Aluminum welding is a lot more common than it used to be, and is taught at the local CC as part of their Agricultural Maintainanece program. The key is getting it done at the right price, otherwise a head swap would be the better choice.
     
  8. Krafty

    Krafty Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    or high school welding class, ( only let the teacher weld it.) and they'll do it for free.

    I had the local highschool welding teacher tig weld the bottom end case of my race bike when a piece of the case chipped off at the drain plug.

    its an easier job than at first it would appear.
     
  9. rocs82650

    rocs82650 Well-Known Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    Agreed; for a experienced tig welder. Tig rig, filler rod and a cylinder of argon would have that fixed right quick (in situ). $40 or a nice bottle of his/her poison/brew of choice as suggested would probably work also.

    Gary H.
     
  10. Expat_Brit

    Expat_Brit New Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    For the record I had a similar issue that was on the intake side of my Seca 750. I say this with caution as I know some "expert" may shoot me down, or at least attempt too. But, If there is sufficient thread engagement, you do not need to worry. You'll only know I guess if you are able to get a stud in there and can torque down on it.

    My issue was similar, but I was able to drill out the old snapped stud, rethread the hole, no heli-coil needed I then used plastic metal around the missing part of the ear or tag with a WD40 wiped stud in place so the plastic metal would not stick to it. Once dry, I back out the stud, draw filed the surface smooth and saved myself welding which could distort the head if not done by a competent welder.

    Just an option, worth a try, as you can do it all in place.
     
  11. Ted

    Ted Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    Thanks for the idears fellas! I'll make a couple calls to the local Tech schools.. we also have a Chopper shop ( https://twistedchoppers.com/ ) right down the road from me that I might check with. They welded a crack in one of the side covers on my other bike for me a couple years back.

    How much aluminum do I have to work with there before we get into the cylinder wall or some other passage? This sounds like a terrible idea but we thought about just drilling in to what's left there and getting a longer bolt or stud... 8O

    Subquestion: I noticed last night that there is a bolt on the right side of the head where there isn't on my other bike. Looks like somebody might have drilled out the plug that was pressed in from the factory - but why!?

    NOTE: looks like I'll have a mess of black RTV to deal with when I check valve clearances.. :roll:
     

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  12. rocs82650

    rocs82650 Well-Known Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    That's the YICS port/passage. Should be a similar one on the other side (left) of the engine.

    Gary H.

    Talk real nice to chopp shop; they should be able to hook you up.
     
  13. Ted

    Ted Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    No, the YICS port is down lower on the back end of the jugs (right?) This is up toward the top of the head.
     

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  14. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    That is an oil gallery plug. Some bikes got pressed in plugs, others got bolts. The reason why remains a mystery.


    I would not suggest drilling the hole deeper. There isn't much metal between the bottom of the existing hole and the combustion chamber.
     
  15. Xjrider92117

    Xjrider92117 Active Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    Plugged.

    [​IMG]
     
  16. Ted

    Ted Member

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    Re: Scored another XJ last night - any NY Giants fans out there?

    Huh. Fair enough.. it's weird that the forward gallery has a plug and the rear one has a bolt but I can't imagine why anyone would go digging around in there so I would agree it probably just came out of the plant that way.


    [/quote] I would not suggest drilling the hole deeper. There isn't much metal between the bottom of the existing hole and the combustion chamber. [/quote]

    Yeaaah that's what I'm thinking too. Probably not enough room to get strong threads in there.

    Anybody know off-hand what the torque specs are for the exhaust flange nuts?

    EDIT: got home and looked at the book: 5.4 lb/ft
     
  17. rocs82650

    rocs82650 Well-Known Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    Sorry bout that. Wasn't looking at pic long enough. My bad.

    Gary H.
     
  18. Ted

    Ted Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    Anybody got a spare 750 head that they would like to get rid of?

    I think this one is FUBAR'd. We did some exploratory drilling and it appears that there is still a piece of the stud (or a piece of easy-out) stuck in the bottom of the hole. Tossing around the idea of getting some good carbide bits to drill a little further or pull the head and bring it to a shop to see if they can fix it but a head swap is starting to look like the best bet.

    Checked the valve clearances just for the hell of it. Everything is tight:

    Intake:

    1 - .102
    2 - .076+
    3 - .051
    4 - .102

    Exhaust:

    1 - .076
    2 - .127
    3 - .152
    4 - .102

    :oops:

    Yeah, I know.. I need a good set of metric feeler gauges.
     
  19. Ted

    Ted Member

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    Re: Scored another XJ last night - any NY Giants fans out th

    Here's a pic of the hole. You can see a little hole in the middle that I belive is the center of the bottom of the stud.(?) It's not pretty. :?

    [​IMG]
     
  20. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    I have 2 - 750 heads
    A Maxim head still on the bike,
    A Seca head on the shelf in the garage
    either will need a valve job due to "exposure"
    I'll check on their overall "integrity" in the daylight.
     

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