1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

85 Maxim X Finally Back Together!

Discussion in 'XJ Technical Chat' started by Medici, Feb 24, 2017.

  1. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    Hey guys, it's been about 4 months that I've had this bike and with little to no experience in working with anything like this. I finally got the carbs put back on after being cleaned, tank put back together after re-lining and rebuilding petcock, and getting my battery all prepped and charged. I put everything back together tonight and went to fire it up but no dice. I'm lucky enough that all my electrics work, can hear my relays clicking away, but still not wanting to fire up. It cranks fine, all new spark plugs, but I can't really seem to pinpoint where my issue is. I know I need to replace the vacuum line from the intake boot on cylinder #2 (and I have no idea how to remove it) but I am not totally sure if that would really be my problem? The carbs are getting fuel and I'm fairly certain I'm getting spark (I'll update on that later today), but one thing I noticed when replacing my spark plugs is that cylinder #2's spark plug had some sort of sandy gunk on the tip? When I put in the new spark plug it almost sounded like sand inside the threads. Looking in the cylinder it looks alright but this gunk was oil-colored and was like dry oil mixed with dirt. Any thoughts?

    Thanks,

    Medici
     
  2. cds1984

    cds1984 Active Member

    Messages:
    902
    Likes Received:
    195
    Trophy Points:
    43
    Location:
    Perth, Western Australia
    Sounds funky but you know a picture is worth a thousand words.
    Can you upload a pic of the sandy gunk on the plug?
     
  3. Stumplifter

    Stumplifter Well-Known Member

    Messages:
    2,792
    Likes Received:
    1,051
    Trophy Points:
    113
    Location:
    near Irma, WI
    Could be PMP

    Did you cover/seal your intakes when the carbs were off?
    How long were they off?
     
  4. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    The carbs were off for approximately 2-3 months. The intakes were loosely stuffed with rags but were left open for about 2 weeks. I have also confirmed that I do have spark and I will be getting a picture of the aforementioned spark plug later tonight or tomorrow morning. Could you clarify what exactly PMP is?
     
  5. XJOE550

    XJOE550 Active Member

    Messages:
    446
    Likes Received:
    75
    Trophy Points:
    28
    Location:
    Inverness, FL
    Take a can of starting fluid and spray two or three shots in each carburator body with the throttle wide open. Than try starting it with the throttle at least half way open. See if she roars to life for a few seconds. If it comes then you will know it must be a fuel issue or air leak and you can start tracking it down. If it doesn't start I would start looking at the spark or timing issue. Have you confirmed your valves don't need adjustment? If not, that's agood place to start. But try the starting fluid even bfore trying that. It's an easy no sweat diagnostic. Good luck.
     
    Stumplifter likes this.
  6. Stumplifter

    Stumplifter Well-Known Member

    Messages:
    2,792
    Likes Received:
    1,051
    Trophy Points:
    113
    Location:
    near Irma, WI
    Pulverized Mouse Parts. o_O
    Those buggers like engines . . . .

    Were the carbs, bench synched and wet set?
    What spark plugs did you use?
     
  7. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    The bike has less than 12k miles on it and the previous owner said he maintained it to certain point, but I understand that should be taken with a grain of salt. I'm fairly certain my valves are alright but I'll most likely end up checking them anyway.

    They were bench synched but not wet set. I did manage to get incredibly accurate float height measurements and set them all accordingly but another question I have is how far should my mixture screws be backed out? I'm currently at 2 and 1/2 turns exactly. We don't really have mice as an issue where I'm at so I'm sure that's not the case. To be honest I was in a bit of a hurry to get the carbs back on because it's taking me quite some time to get a lot of these tasks done (seeing as how I don't really know what I'm doing) so I'm taking it slow. I'll try the starter fluid method but I would really like to confirm integrity of the engine above all else. I have compression but other than that it's a mystery to me because most of the check I need to do I am not even aware of. Also I am using NGK D8EA spark plugs, exact replacements for what were originally on the bike. Just to confirm and cross-reference what should my gap be set to?
     
  8. Stumplifter

    Stumplifter Well-Known Member

    Messages:
    2,792
    Likes Received:
    1,051
    Trophy Points:
    113
    Location:
    near Irma, WI
    Hmmm, don't know the Maxim X specs. I know an 81 Maxim takes a different plug.
    0.7 - 0.8 mm for a gap (again on an XJ Maxim).

    Perhaps I'll just stand down, as I have been wrong to compare my knowledge of a particular Yamaha with different models.

    Good luck and glad you don't have mice (although our dogs, cats and local avian/small mammals find them quite entertaining here!).
     
  9. hogfiddles

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

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    Gap won't be the issue. at less than 12k, clearances won't be the issue.

    If you have spark, then that seems narrow it all back down to the carbs/fuel delivery
     
    k-moe likes this.
  10. k-moe

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

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
  11. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    Well I finally got back around to tinkering and at full choke she fired right up! sounded pretty good but the previous owner had spilled some nasty oil on the side of the engine so it was smoking the hell out of my garage. Didn't want to idle but I suppose I should just richen my mixture and play with my idle adjustment and I'm off to the races!
     
  12. Simmy

    Simmy Well-Known Member

    Messages:
    2,261
    Likes Received:
    1,126
    Trophy Points:
    113
    Location:
    Waterloo Ontario Canada
    Well done, always feels good bringing old stuff back to life.
     
  13. XJOE550

    XJOE550 Active Member

    Messages:
    446
    Likes Received:
    75
    Trophy Points:
    28
    Location:
    Inverness, FL
    Was applying full choke all that was needed for her to fire up? Or was there some other adjustment or change you had to make before it fired up for you?
     
    k-moe likes this.
  14. k-moe

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

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    We all would like to know.
     
  15. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    Yes, sorry for the late reply. At full choke it started right up. I imagine the next logical step would be to synchronize the carburetors? If that is the case then I have a few questions about the process seeing as how from everything I've seen only applies to bikes with non-vacuum petcocks. This may be an issue seeing as how I have a vacuum petcock.

    EDIT: It should be noted that upon startup all carburetors were bench synced (honestly needed almost no adjustment whatsoever) and sync/mixture screws were all backed out to the specified 2 1/2 turns.
     
  16. k-moe

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

    Messages:
    19,613
    Likes Received:
    6,703
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    are you able to gradually shut the choke off as the engine warms, or will it stall?
     
  17. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    It'll die if you shut off the choke but I never had it running long enough to really get it warm because some concern over the quality/age of the oil. I'm gonna be getting my oil filter in the mail soon and do an oil change and we'll see then once it's warm. To be honest though I don't think it will change anything. The idle screw wasn't set whatsoever when starting this first time.
     
  18. XJOE550

    XJOE550 Active Member

    Messages:
    446
    Likes Received:
    75
    Trophy Points:
    28
    Location:
    Inverness, FL
    Glad to hear. Bench sync may not be enough. This will only make the carburetors equeal but not the engine. Not all four cylinders may be peforming equally. The compression can be different between different cylinders due to wear of the rings walls or valve adjustement/seating, etc. Vacuum balancing will balance the engine power to conpensate for these variables in cylinder perofrmance. You may able to use the bikes own tank as a fuel source while sync'ing. You can see I was able to do so in this video in the link below. Different bike, but gives you an idea.

    http://www.xjbikes.com/forums/threads/xj550-seca-carburetor-balancing.58149/

    It has a vacuum petcock as well. But if you set the petcock on prime, it effectively becomes a gravity feed fuel source. I used some blocks of wood to raise the tank and was able to get at the adjuster screws. You may not be able to get away with doing so without taking the tank off. In wich case you can try setting the tank above the carbs on a small table or what ever. And have some extra fuel hose to extend the reach to the carbs. Or, use some kind of other auxiliary tank. By the way, you should be able to get the filter from Advanced Auto Parts. They may have to get it for you from their warehouse. But I think the sell them for around $12 or so.
     
    Stumplifter likes this.
  19. Stumplifter

    Stumplifter Well-Known Member

    Messages:
    2,792
    Likes Received:
    1,051
    Trophy Points:
    113
    Location:
    near Irma, WI
    ^^^ yep, running vacuum synch
    block of wood under tank, switch to prime.
     
  20. Medici

    Medici Member

    Messages:
    46
    Likes Received:
    10
    Trophy Points:
    8
    Location:
    St. Louis, MO
    Where does the vacuum line outlet on the petcock attach in relation to the manometer/carb sync tool setup? An explanation of the system would be appreciated because I cannot seem to work it out in my head.
     

Share This Page