Page 1 of 2 1 2 LastLast
Results 1 to 10 of 16
  1. #1

    Join Date
    Nov 2014
    Location
    Noosa Australia
    Posts
    9

    Polaris msx140 questions compression and more

    Hello all,

    It seems this site has some great information on it for a new comer to the sport like myself.

    i have recently purchased a 2004 Polaris msx140 (first ski) and have put 5 hours on to it only to be told by a local boat mechanic that I have to spend close to $5000 on a top end re build due to low compression!

    The he ski seems to run spot on assist from a slight miss fire at about 2500 -3000 rpm, after that she is super smooth and goes like a cat chased by a bucket of water.(fast and agile).

    i have had a compression test and it shows the following on the three cylinders in order of 115- 118 - 100 psi.

    The he ski seems to make no noise at all that leads me to believe it has major issues but when all spark plugs are out and she is cranked it does make a slight knock noise on the back cylinder which shows 100psi....

    wondering if if anyone knows what factory psi the pots are meant to have and if I should be concerned about the pots being so different in readings and the strangle subtle knock.

    i have just paid 4500 for the ski so the concept of spending another 5 k on rebuilds scares me a bit. I have also been told by another experienced jetski riding mate that it seems the mechanic is trying to take advantage of my lack of knowledge.

    i am however very mechanically minded so hope I can sort out the potential issues myself.

    cheers!


  2. #2

    Join Date
    Nov 2014
    Location
    Noosa Australia
    Posts
    9
    Sorry about the grammar issues, my iPhone has a mind of its own!

  3. #3
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,708
    +1
    1,324
    My msx cranks 120 psi. That 100 psi cylinder definitely needs attention especially if you are hearing noises from it.

  4. +1 by:


  5. #4
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,599
    +1
    1,276
    For $5000 Aus one of us could fly down there WITH an entire rebuilt engine, install it, then holiday and ride around with you for a week!

    These are large 2-stroke engines, but not that hard to work on. See my signature links for lots of useful info.

    The cylinders are Nikasil coated, no iron sleeves. If a cylinder becomes worn then the cylinder wear surface is repaired as needed and replated. This is typically done by a cylinder replacing company. So the replacement piston is not oversized, it remains OEM size and spec.

    If the crankshaft main bearings (or the connecting rod big end bearings) are damaged or worn then the entire crankshaft must be rebuilt. These cranks are assembled using a 25 ton press so the crank must come apart to replace the inner bearings.

    I would not continue to ride it until you have investigated the engine noises.

    Note: These Ficht direct injection engines require the NGK PZFR6H spark plugs, no substitutes.

    The cylinder heads are sealed with two large o-rings, no head gasket. The inner o-ring is a high temperature material.

    The fuel injectors can be unbolted and lifted from the heads. Release air pressure from the fuel tank before you loosen the injectors. The brackets over the injectors also retain the fuel hose fittings, lift the brackets away then the fuel hoses wiggle out.

    Mark each fuel injector with the cylinder it came from, they are not interchangeable.

  6. +1 by:


  7. #5

    Join Date
    Nov 2014
    Location
    Noosa Australia
    Posts
    9
    That's some great information guys, cheers! the knock is a strange one as its only on the back cylinder? so i'm thinking its not the crank shaft ect. Seems more so to me to be a piston slap noise? NOTE: Does not make any strange noises with plugs in and running.

    I am a bit strapped for cash at the moment but also want use out of the ski for the christmas break. I also don't want to break it any further either...

    What is your impression on the sleeve option? i can get this for $145.00 plus a new piston kit for the one cylinder for $120.00 au. Then i would only need it machined for the 84mm piston?

    This sounds like the most cost efficient option and would allow me to re do the other two cylinders early next year.

    Click image for larger version. 

Name:	IMG_2519.jpg 
Views:	39 
Size:	94.0 KB 
ID:	347394

  8. #6
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,599
    +1
    1,276
    Quote Originally Posted by Dozer View Post
    That's some great information guys, cheers! the knock is a strange one as its only on the back cylinder? so i'm thinking its not the crank shaft ect. Seems more so to me to be a piston slap noise? NOTE: Does not make any strange noises with plugs in and running.

    I am a bit strapped for cash at the moment but also want use out of the ski for the christmas break. I also don't want to break it any further either...

    What is your impression on the sleeve option? i can get this for $145.00 plus a new piston kit for the one cylinder for $120.00 au. Then i would only need it machined for the 84mm piston?

    This sounds like the most cost efficient option and would allow me to re do the other two cylinders early next year.

    Click image for larger version. 

Name:	IMG_2519.jpg 
Views:	39 
Size:	94.0 KB 
ID:	347394
    It sounds like you are making assumptions regarding the internal condition of the engine. Until you mechanically investigate there is guesswork involved.

    If you want the engine to be a trustworthy state one month from today, you really do need to know what state of affairs the engine is in.

    Don't omit checking or servicing everything else in the machine, from jet pump to fuel pump. It takes some time and effort to work through it all.

    What cylinder sleeving option are you referring to?

    The cylinder porting on the MSX 140 cylinders is different from the Polaris red engine. Sleeves made for the 1165cc red engine will not work properly in the 1192cc MSX 140 engine.

  9. +1 by:


  10. #7

    Join Date
    Nov 2014
    Location
    Noosa Australia
    Posts
    9
    I hear you bud, i have it booked in two weeks from now for a check up by a reputable mechanic and hope he will deliver some good news. The only reason i'm thinking piston slap is because iv'e heard it before in a two stroke motorbike.

    And if it were to be bottom end [crank ect] it would make the noise on all pots?

    Could even be a worn rod bearing for that pot causing some movement i suppose.

    The sleeve i was referring to is a cylinder sleeve insert to replace a potentially damaged cylinder wall. Just figure this might be a safer way to proceed as i have a long wait for any items i have to order in from the states.

    Thanks for the tip re the red motor too, good to know!

  11. #8

    Join Date
    Nov 2014
    Location
    Noosa Australia
    Posts
    9
    Thanks Bryan, so is 120 psi the factory pot rating.

  12. #9
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,599
    +1
    1,276
    Quote Originally Posted by Dozer View Post
    ?..

    Could even be a worn rod bearing for that pot causing some movement i suppose.

    The sleeve i was referring to is a cylinder sleeve insert to replace a potentially damaged cylinder wall. Just figure this might be a safer way to proceed as i have a long wait for any items i have to order in from the states.
    Order a replacement new/good used/replated MSX 140 cylinder and piston kit now. It can be there by the time of your mechanic appointment.

    Pistons can be OEM Polaris or aftermarket. My own rebuilt MSX 140 has aftermarket snowmobile pistons. Just make sure you order the right piston! Not the same pistons as the red '1200' engine.

    Not sure what you mean by 'a safer way to proceed'. Sleeving a cylinder is going to affect the porting. Unless all three are done the same way the engine might run 'different'.

    These Ficht engines do not have an air flow sensor. The entire system is based on the engine having a stock air flow and combustion parameters. If the air flow is improved the fuel delivery will not change, leading to possible lean burn engine damage.

  13. #10

    Join Date
    Nov 2014
    Location
    Noosa Australia
    Posts
    9
    Quote Originally Posted by K447 View Post
    Quote Originally Posted by Dozer View Post
    ?..

    Could even be a worn rod bearing for that pot causing some movement i suppose.

    The sleeve i was referring to is a cylinder sleeve insert to replace a potentially damaged cylinder wall. Just figure this might be a safer way to proceed as i have a long wait for any items i have to order in from the states.
    Order a replacement new/good used/replated MSX 140 cylinder and piston kit now. It can be there by the time of your mechanic appointment.

    Pistons can be OEM Polaris or aftermarket. My own rebuilt MSX 140 has aftermarket snowmobile pistons. Just make sure you order the right piston! Not the same pistons as the red '1200' engine.

    Not sure what you mean by 'a safer way to proceed'. Sleeving a cylinder is going to affect the porting. Unless all three are done the same way the engine might run 'different'.

    These Ficht engines do not have an air flow sensor. The entire system is based on the engine having a stock air flow and combustion parameters. If the air flow is improved the fuel delivery will not change, leading to possible lean burn engine damage.

    Thanks k's for the effort in your replys bud, yes I think you are on to something.

    i have been in contact with the only polaris stockist here in Australia (ex polaris dealer) and he told me that their is no after market piston set available for the msx140 and the sleeve kit I was looking at will damage the motor further. Sounded like he knew what he was talking about...

    so it seems I have bought the porche (expensive) version of ski here. He quoted me $290.00 for (one piston) with rings and pins and a further $580.00 for a re conditioned cylinder and that is a swap over price.

    and that's not including any gaskets or I rings which I may need!

    does this seem overly excessive?

Page 1 of 2 1 2 LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. 93 Polaris 750sl odd compression and running strange
    By waco4g63 in forum Polaris PWC Performance
    Replies: 2
    Last Post: 05-18-2014, 05:13 PM
  2. polaris msx140 jetski r and d scoop grate
    By keith m in forum Polaris PWC Performance
    Replies: 0
    Last Post: 02-27-2010, 04:54 PM
  3. 2004 polaris octane 4 sale, Brand New Novi 48mm and More
    By superstock1986 in forum Polaris Classifieds
    Replies: 4
    Last Post: 09-14-2008, 05:20 PM
  4. Newbie questions about holes in 96 Challenger and more...
    By PilotSmith in forum Sea Doo Sport Boats
    Replies: 8
    Last Post: 01-30-2008, 05:50 PM
  5. Polaris sl750 questions (waterleak and trim)
    By smittyj77 in forum Polaris Open Discussion
    Replies: 10
    Last Post: 05-24-2007, 03:52 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
  •