pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» wallpapers

Page 1 of 2 12 LastLast
Results 1 to 10 of 16
  1. #1
    PWCToday Newbie
    Join Date
    Mar 2009
    Location
    United Kingdom
    Age
    33
    Posts
    33

    650sx compression

    Hi,
    Just done a compression test on my 650sx this afternoon. 125 and 135psi were the readings. Is this pressure acceptable for a stock ski or not? I have just done a rebuild on the ski to clean the engine and powder coat it. I put a new gasket set and crank seals on the engine. The bore's looked like new so I didn't put new rings on.

    Is it possible to machine the stock head and if so how much do i need to take off to increase compression to arround 165-70psi?

    Thanks Guys, sorry for all questions!

  2. #2
    PWCToday Regular
    Join Date
    Jun 2008
    Location
    Saugus/ So Cal
    Age
    22
    Posts
    119

    Re: 650sx compression

    costworth, my stock 650 was running 130 both holes, i sent the head out the get milled .020 and am getting it back today, if you want ill post my data

  3. #3
    PWCToday Newbie
    Join Date
    Mar 2009
    Location
    United Kingdom
    Age
    33
    Posts
    33

    Re: 650sx compression

    Yes, please report the results!

  4. #4
    Frequent Poster u887266's Avatar
    Join Date
    Nov 2008
    Location
    Texas
    Age
    32
    Posts
    179

    Re: 650sx compression

    If it was me and I might be wrong, but if you rering the engine I would run the engine first to let the rings get set in and also let the engine heat up, then take the compression check. More then likely you will get a different reading.

  5. #5
    PWCToday Newbie
    Join Date
    Mar 2009
    Location
    United Kingdom
    Age
    33
    Posts
    33

    Re: 650sx compression

    I Didn't put new rings in, so they should already be bed in. I have checked the compression also while the engine is hot!

  6. #6
    PWCToday Regular
    Join Date
    Jun 2008
    Location
    Saugus/ So Cal
    Age
    22
    Posts
    119

    Re: 650sx compression

    well, head is on, but i just happen to loose the tourque wrench adapter so i think they are around 14 or 15ft lbs right now and the psi is dissapointingly the same

  7. #7
    PWCToday Newbie
    Join Date
    Mar 2009
    Location
    United Kingdom
    Age
    33
    Posts
    33

    Re: 650sx compression

    That don't make sense! You have reduced the volume so compression must be higher?

  8. #8
    PWCToday Regular
    Join Date
    Jun 2008
    Location
    Saugus/ So Cal
    Age
    22
    Posts
    119

    Re: 650sx compression

    i know! idk what the deal is.. i picked up the head..ran down and picked up a gasket......bolted it down to about 14ftlbs and it was 130.. i highly doubt tourquing it down the 22ftlbs is going to change the psi at all..

  9. #9
    PWCToday Regular
    Join Date
    Apr 2008
    Location
    ct
    Age
    33
    Posts
    140

    Re: 650sx compression

    I put new pistons in and honed the cylinders in my stock ski with standerd bore 87 650sx. Before brake in it was 145psi in each. I think 130 is a little low. You may want to rebuild. I haven't checked it yet but I bet its close to 150 now.
    Last edited by ljbarryiv; 04-08-2009 at 08:58 AM.

  10. #10
    Frequent Poster 64coupe's Avatar
    Join Date
    Jul 2008
    Location
    PA
    Age
    29
    Posts
    277

    Re: 650sx compression

    Quote Originally Posted by ScatteredFormat View Post
    i know! idk what the deal is.. i picked up the head..ran down and picked up a gasket......bolted it down to about 14ftlbs and it was 130.. i highly doubt tourquing it down the 22ftlbs is going to change the psi at all..

    What was the head gasket you picked up? Did you have an after market one on there before the milling that was thinner? Just a thought?

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.2.0