Results 1 to 10 of 10
  1. #1

    2002 XLT 1200 rear cylinder compression

    I just picked up a cheap XLT 1200 off craigslist that was said to not run. It had been sitting for about 2 years. I rented a cheap (I have since ordered a good one) compression tester and the front and middle cylinder both read 100 psi. The rear cylinder shows 0. I installed a new battery and put in fresh gas and oil, new plugs, and the thing started right up and idled nice. I hooked the hose up to it and let it idle for about 5 minutes with no issues. The next morning I tested the compression again and had the same numbers as before.

    I took the head cover off and everything inside looks fine, the pistons are all in good condition from what I can tell so far, and the cylinder walls are all nice and smooth. I took the covers off the power valves and I definitely need to clean them before I install the new waveeater clips.

    My question is, what would cause the rear cylinder to read 0 psi when visually everything looks fine. Are the rings bad? If so, is it possible to just replace the rings? I am going to install a D plate and remove the cat, waveeater clips, and possibly go premix. I just want to make sure I don't need a full rebuild before I start doing this stuff.


  2. #2
    Happily Self-Employed WFO's Avatar
    Join Date
    Nov 2005
    Location
    Houston, Texas
    Posts
    12,801
    +1
    450
    If the #3 is showing zero compression then you have a big problem. The piston may have scoring marks that arent visable from the top.

  3. #3
    Forgot to add that all oil lines were still attached

  4. #4
    Quote Originally Posted by WFO View Post
    If the #3 is showing zero compression then you have a big problem. The piston may have scoring marks that arent visable from the top.
    So is the next step to remove the piston? I have another cylinder and piston from a 1999 XL 1200 limited, could I use this in the 2001 xlt?

  5. #5
    Happily Self-Employed WFO's Avatar
    Join Date
    Nov 2005
    Location
    Houston, Texas
    Posts
    12,801
    +1
    450
    man... that's a tough one, but it it was me I would have pulled the cylinder off and checked it all out... weird that there are no signs of damage on the cyl walls

    another thought... in theory it could have broken reed petals on that cylinder

  6. #6
    I'll go ahead and pull the cylinder off and check the piston. When I first checked the compression, it was 30 psi, but when I pulled off the head cover I noticed a lot of oil inside the cylinder from I'm guessing where it has not been run in a couple years. After I got it started and let it idle on the hose for a few minutes, and pulled the head cover off again, all that extra oil was gone. I rechecked the compression and it was reading 0 psi. I'm thinking the extra oil caused the higher reading. I'll check the reeds also, is that difficult to do?

  7. #7
    Happily Self-Employed WFO's Avatar
    Join Date
    Nov 2005
    Location
    Houston, Texas
    Posts
    12,801
    +1
    450
    the reeds are behind the the plate that is behind the carbs

  8. #8
    I'm going to take the carbs off to have them rebuilt anyway, so I'll check them while I'm in there

  9. #9
    Happily Self-Employed WFO's Avatar
    Join Date
    Nov 2005
    Location
    Houston, Texas
    Posts
    12,801
    +1
    450
    I always clean the rubber imbedded gaskets one the reed cages real good and seal the cages front and back... the silver reed cover plate is bad about leaking

  10. #10
    Update: I went ahead and pulled the cylinder and found the piston is bad. The sides of the piston are scored, but the cylinder walls are nice and smooth. So, should I go ahead and replace all the Pistons or just the bad one? I've already installed the oil pump block off and will be sending the carbs off to be rebuilt.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. 2002 XLT 1200 Blown Cylinder #2 Help! with Pictures!
    By TaulmanServices in forum Yamaha PWC Performance (2-stroke)
    Replies: 11
    Last Post: 08-28-2015, 07:12 AM
  2. Replacing Multiple Cylinders on 2 x 2002 XLT 1200s?
    By TaulmanServices in forum Yamaha PWC Performance (2-stroke)
    Replies: 8
    Last Post: 08-27-2015, 04:14 PM
  3. Old cylinder heads ~ 2002 XLT 1200 Waverunner
    By Sflwaverunner in forum Yamaha PWC Performance (2-stroke)
    Replies: 9
    Last Post: 11-25-2010, 01:00 PM
  4. WTB 2002 xlt 1200 cylinder
    By sonnyxl1200 in forum Yamaha Classifieds
    Replies: 5
    Last Post: 05-16-2010, 10:40 AM
  5. Stinger Removal in a 2002 xlt 1200
    By crownline99 in forum Yamaha How To & FAQs
    Replies: 5
    Last Post: 04-08-2009, 09:28 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •