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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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    Looking on ebay and amazon for the intake boots some say they will not fit, if its a yamaha head but will fit if its YICS and some say they are junk ..any advice guys .... my old ones are not cracked on the inside but they may have been mixed up over the years regarding the sync port locations
     
  2. k-moe

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

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    Contact @chacal either through a conversation here or email info@xj4ever.com
    He has the correct non-junk intake parts.
     
  3. glennyboy

    glennyboy Member

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    thanks
     
  4. glennyboy

    glennyboy Member

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    xj4ever boots are 50 bucks each plus tax and shipping....i will either leave the ones i have on now or go with amazon, at least i can send them back ....
     
  5. k-moe

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

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    The ones on Amazon are total junk. Waste of money and time. Chacal used to sell them until we all started seeing internal failures. A failure type that IMO creates the possibility of debris from the boot entering the combustion chamber and causing a very expensive repair.

    If your budget is that tight then you can repair the boots you have.
    Clean and degrease them thoroughly. Then (wearing gloves) use black oil-resistant RTV to fill in the cracks and cover the surface of the boots. You can smooth the surface of the RTV by wetting your finger and going over your work.
    That method is what we all used before replacement intake boots became available again.
     
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  6. jayrodoh

    jayrodoh YimYam Premium Member

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    Mixing them up won’t matter, if not cracked then why are you replacing?
     
  7. glennyboy

    glennyboy Member

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    On #3 cylinder the vac connection is pointing down to the right, almost touching #4.. swapping them 4 to 3 puts the line up off, carbs would not fit...been that way a long time ..so can not remove cap to do sync, they must have been replaced before, long time ago rubber is hard... Decided to go ebay if they are junk i can send them back no charge...
     
  8. glennyboy

    glennyboy Member

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    Plus eliminating the boots... i have a big problem that i can not solve, surge on highway after 1/4 throttle ease back to 1/4 and its ok... had carbs apart/cleaned passages for the third time, found nothing.. ready to go back on... valve clearance ok... pulling away 1st 2nd 3rd through gears, flat spot.. feels like fuel on then off ?... this is the bike that never ran for 21 years
     
  9. Huntchuks

    Huntchuks Well-Known Member

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    That is strange. Maybe remove boot #4, wrench off the vacuum cap of #3, put a vacuum line extension on #3, add a straight vacuum connector to the end, cap off the connector, reconnect boot #4. May not be pretty but would allow vacuum syncing your carbs.
     
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  10. glennyboy

    glennyboy Member

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    Thanks ... boots on the way.. looking at the rubber up top no tears bit out of shape
    IMG_20220705_093330245_HDR.jpg
     
  11. Huntchuks

    Huntchuks Well-Known Member

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    Did you remove from carb and slightly stretch all round while holding up to a light source?
     
  12. jayrodoh

    jayrodoh YimYam Premium Member

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    That is odd, there are different intakes for YICS and non-YICS motor. I have no idea if they are interchangeable but you must have a mix of intakes I'm thinking! Hard to say what PO's did over the last 40+ years.
     
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  13. glennyboy

    glennyboy Member

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    Yes checked the rubber diaphragm several times stretching for cracks ..none .... yes mix of intakes for sure interchangeable yes, but the vac ports must be different place... getting set off ebay cheap 22 bucks with gaskets.. made in China .... my 650 has the YICS badge in the cover but who knows its life could have a non YICS head.....
     
    Last edited: Jul 5, 2022
  14. jayrodoh

    jayrodoh YimYam Premium Member

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    How’d you know what to order then? Got a pic, we can confirm!
     
  15. k-moe

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

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    Even then all of the vacuum ports should point straight up. The non YICS boots are at a different angle horizontally, but all have the vacuum ports at 12 o'clock.
     
  16. k-moe

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

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    The YICS head has a distinct manifold at the rear of the head with blocking bolts at either end. The non-YICS valve cover does not fit onto the YICS head.
     
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  17. glennyboy

    glennyboy Member

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    Any pictures of head not sure what you mean blocking bolts at either end
     
  18. jayrodoh

    jayrodoh YimYam Premium Member

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    MC.jpg
     
  19. glennyboy

    glennyboy Member

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    Thanks for the picture, i see now... no i dont have the YICS head, production date on my 650 is 6/80.... back to my carbs, i will bring the float level up 3 mm so its close to the bowl gasket, get rid of the mesh screen above float needle couple have splits ... i have the brass in line filter that should do...
     
  20. jayrodoh

    jayrodoh YimYam Premium Member

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    Cool, the ones you ordered should all be the same then. The YICS motor use two left and two right, non-YICS are all the same. Len's catalog confirmed that the same manifolds that are used on non-YICS are the same as the right two on a YICS motor which makes me think you have some upside down or from a YICS motor all mixed up.
     
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