1. Some members were not receiving emails sent from XJbikes.com. For example: "Forgot your password?" function to reset your password would not send email to some members. I believe this has been resolved now. Please use "Contact Us" form (see page footer link) if you still have email issues. SnoSheriff

    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.

1983 xj750 k manifold vacuum

Discussion in 'XJ Technical Chat' started by Ken Madden, Aug 24, 2019.

Tags:
?

I'm looking for the average manifold vacuum level I should be seeing

  1. How many inches of mercury

    0 vote(s)
    0.0%

  2. Inches of mercury

    0 vote(s)
    0.0%
  1. Ken Madden

    Ken Madden New Member

    Messages:
    16
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    USA
    Can anyone tell me the average manifold vacuum level I should be seeing on my carbs?
     
    Ken Madden, Aug 24, 2019
    #1
  2. Toomanybikes

    Toomanybikes Well-Known Member

    Messages:
    2,836
    Likes Received:
    815
    Trophy Points:
    113
    Location:
    Tsawwassen bc
    Once they are even as idle is 1050rpm 10-12
     
    Toomanybikes, Aug 24, 2019
    #2
  3. Ken Madden

    Ken Madden New Member

    Messages:
    16
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    USA
    I'm only seeing 7. Might be the crappy gages I bought. The bike idles great
     
    Ken Madden, Aug 24, 2019
    #3
  4. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,861
    Trophy Points:
    113
    Location:
    Great North Woods
    you are looking for equal or as close to equal after sync.

    it will be different on different gauges.
     
    XJ550H, Aug 24, 2019
    #4
  5. k-moe

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

    Messages:
    19,647
    Likes Received:
    6,756
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    Actually it shouldn't be, unless inexpensive dial gauges are being used.

    OP, here's the thing. Yamaha didn't give a spec for manifold vacuum since there are no vacuum accessories other than the petcock. You also can't go by any chart or guide that was made for a different engine type. The only real way to gauge the internal health of the enigne is to perform compression and leakdown tests. As it stands you don't seem to really need to do either.
     
    k-moe, Aug 24, 2019
    #5
  6. Ken Madden

    Ken Madden New Member

    Messages:
    16
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    USA
    By the way thank you so much for the response
     
    Ken Madden, Aug 24, 2019
    #6
  7. Ken Madden

    Ken Madden New Member

    Messages:
    16
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    USA
    Well I am getting ready to colortune. We'll see if that makes any difference at all on the manifold vacuum. The bike performs really well lots of spunk. It only has 7,200 miles on it.
     
    Ken Madden, Aug 24, 2019
    #7

Share This Page