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1981 XJ650 maxim intake boots YICS

Discussion in 'XJ Technical Chat' started by glennyboy, Jul 4, 2022.

  1. glennyboy

    glennyboy Member

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  2. glennyboy

    glennyboy Member

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  3. jayrodoh

    jayrodoh YimYam Premium Member

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    Based on the description and pics those are the wrong ones, you’ll end up with the vac nipples in the wrong spot like you currently have.
     
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  4. glennyboy

    glennyboy Member

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    Thanks.. i see that now... i will stick with the ones i have now, and do what huntchucks said fit extension the #3 cap
     
    Last edited: Jul 6, 2022
  5. k-moe

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

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    Do the carbs actually fit correctly doing that? Like without any vacuum leaks?
     
  6. glennyboy

    glennyboy Member

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    Yes good and tight no vac leaks just the ports different... Bit of a fight fitting the carb to airbox boots .. working on that... Been like that for years
     
  7. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Ummm.....intake manifolds have compound curves: INWARDS, towards the centerline of the bike (so #1 and #2 curve "to the right" looking from the rear of the bike forward, and #3 and #4 curve "to the left"), and they also curve UPWARDS (towards the sky, or in other words, in the direction that the vac nipple is pointing).

    Fitting the incorrect LH manifolds onto the RH side will maintain the correct "inward/towards the centerline of the bike" curvature, but leaves the manifolds curving "downwards" (towards the engine). The center-to-center spacing for all the carb throats will still be the same, but the carbs will be "tilted" down, and to the right, by a somewhat significant amount.
     
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  8. hogfiddles

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

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    I would NOT trust that set. Simply because it says “fits ‘81-83 xj650 .......
    ‘80-‘81 are DIFFERENT THAN ‘82-‘83.
     
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  9. k-moe

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

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    Been like that for years and isn’t running right. Your fuel levels in the float bowls will be off, as per Chacal’s post.
     
  10. glennyboy

    glennyboy Member

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    IMG_20220706_233015155_HDR.jpg Carbs fit perfect how's this look.. had to fit inner boots to airbox first it's all 42 years old.
     
    Last edited: Jul 7, 2022
  11. glennyboy

    glennyboy Member

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    So should the carbs be level, looked at other 650s and they all tilt .. I had no problem fitting carbs all lined up,.. the airbox lines up ok .. the bikes on the center stand so the rear wheel is up in the air making it worse,, could that tilt be my bogging down problem
     
    Last edited: Jul 7, 2022
  12. glennyboy

    glennyboy Member

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    Found this youtube video mint xj 650 ..8.20 minutes in shows the carbs and they are tilted..... getting back to the boots anyone found my correct boots on e bay


     
  13. jayrodoh

    jayrodoh YimYam Premium Member

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    If it were me I would get the correct manifolds, you already committed to buying a set why not get the right ones. Looking at your pic I can see one is covered with JB weld, plus you can see that the right ones (3,4) are lower then the left set since they are on upside down and do not "curve out and up" correctly. I cannot imagine the boots are tight having them not line up and the carbs would most likely end up at the wrong angle.

    The carbs will have a little tilt to them when installed correctly.

    Why not buy them from Len and know you have the correct ones that won't fall apart in short order? I know they're a little more expensive but its a quality part and the service is second to none. I'll dig up my pic of my aftermarket intakes after a few days.

    Good luck on eBay, I poked around and there are many that are listed incorrectly both in description and pics. If I was attempting it, these look correct by the pic but I wouldn't guarantee it as the description again is wrong on the years and the OEM part numbers listed.

    https://www.ebay.com/itm/323365273599?fits=Submodel:XJ650|Year:1980&hash=item4b4a127fff:g:ZVwAAOSwMDJgG2mH
     
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  14. glennyboy

    glennyboy Member

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    Thanks for that info... used superglue to fill the cracks turned grey lol ..i sent a couple of members a note on the boots they bought for there 1980 xj. see what i get back... the last owner rode the bike three years like this until he parked it up, said it ran ok...But yes the boots are wrong would this cause my bogging down problem?... no vacuum leaks before i pulled the carbs last run out ..went through a can spraying.... clamps good and tight.... that ebay link you sent seems the right boots....... i have $1150 into this project bike so far ... yeah i know it never ends lol
     
    Last edited: Jul 7, 2022
  15. k-moe

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

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    If the carbs aren't sitting at the correct angle to begin with then the fuel levels won't stay within the range that they need to be in while riding.
    So yes, that is a potential source of your bog. Fuel starvation due to low fuel level in one or more float bowls.
     
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  16. glennyboy

    glennyboy Member

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    Decided to take it on test ride... bloody hell no carb problem, ran perfect so my second carb clean did the trick must have missed something ..could have been the needle mixture passages ...what else did i do, ah yes up the fuel level 3mm... made sure the air filter boots were on tight no leaks..... all plugs tan color mixture 2.5 turns out.... thanks for all the help guys... next job i need to replace the side stand frame bracket
     
  17. hogfiddles

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

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    And I’m working on getting that for ya
     
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  18. glennyboy

    glennyboy Member

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    Great thanks
     
  19. glennyboy

    glennyboy Member

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    Well was i wrong should have gone on longer ride.... today i took it on its maiden voyage to speak sixty miles ten freeway, rest canyons /two steep grades pulled like a freight train steady throttle ok .. now winding it to full throttle it pulls all the way through the slight surge 85 mph.+.. so i still got a bit surge ... came home and re set mixture, seems to idle smooth at about 1.5 turns each carb.... Wrong..back on road again this made the surge worse, so back home again lift tank turned 2.5 out each carb.... re test back (dam a bee stung me on the knee...jeans lol)...to where i started when i first went out...So i will be getting the right intake boots like you guys said
     
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  20. glennyboy

    glennyboy Member

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    going off the part number these boots are for the 80/81 model 4h7-1358602 right .. 5g21359601 left... found a set on e bay contacted seller, port location
     
    Last edited: Jul 9, 2022

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