Page 3 of 6 FirstFirst 12345 ... LastLast
Results 21 to 30 of 57
  1. #21
    they sure as shit had ecu and electrical problems that would render them useless or event totaled at $1300 an ecu ...

    Quote Originally Posted by cjk6119 View Post
    The problems with Yamaha heads cracking, is that just related to the supercharged engines or both, naturally aspirated and supercharged are having problems with their heads?

    Engines that are detonating will tend to overheat, because the boundary layer of gases gets interrupted against the cylinder head and heat gets transferred from the combustion chamber into the cylinder head. This might be from not using the correct octane level.

    You know what's interesting here is, when Honda had a ski on the market it seemed to be problem free for the most part. They did not have a pattern of heads cracking, clutches breaking down and they ran a turbo chargers on their engines, and for the most part was trouble free with that setup. It looked to be a very reliable platform to build on.

    CJ


  2. #22
    dcuhpw's Avatar
    Join Date
    Jan 2019
    Location
    Guam
    Posts
    352
    +1
    16
    Quote Originally Posted by big john View Post
    IMO the most likely cause is shutting the motor off after a hard hot run without allowing it to cool off by letting it idle around for a few minutes, or restarting a hot motor and blasting it with cold water. water does circulate thru the head before the thermostat opens, but when it reaches temp it allows maximum water flow to cool the motor. ive always idled/low rpm for a couple minutes to bring the engines down after a hot run, almost 300 hours between two ski and no cracked heads. remember that the motor drains out when its not running and that head is hot af with nothing in it to absorb the heat. everyone know not to pour cold water into a hot engine
    YES, I completely agree. Older kawi ultras have the same issue. Interestingly enough, here on Guam were water temps never dip below about 82 there have been no reports of cracked heads from either the Yami or Kawi dealerships (I know the lead techs).

  3. #23
    Hmmm yea here in seabrook when I ride the water is 75 for a couple of weeks then goes to 80+ and I don’t hear about many heads cracking.

  4. #24
    John F.'s Avatar
    Join Date
    Jul 2005
    Location
    League City, TX
    Posts
    198
    +1
    28
    Quote Originally Posted by seabrook View Post
    Hmmm yea here in seabrook when I ride the water is 75 for a couple of weeks then goes to 80+ and I don’t hear about many heads cracking.
    I ride in the same area as you and have had 3 heads crack and my friend I ride with has had at least 1 head crack as well.
    We both do proper warm up and cool down of the skis and monitor engine temps.
    I believe there is a of casting flaw in some of these heads.

  5. #25
    Quote Originally Posted by John F. View Post
    I ride in the same area as you and have had 3 heads crack and my friend I ride with has had at least 1 head crack as well.
    We both do proper warm up and cool down of the skis and monitor engine temps.
    I believe there is a of casting flaw in some of these heads.
    I'm on the casting flaw train. I ride I the same area as speeder and have had my fzr since 2009 and running 15psi boost since 2012. The only wild card is my heavily modded cooling system. I keep things running really quite cool.

  6. #26

    Join Date
    Nov 2018
    Location
    North Carolina on Jordan Lake
    Posts
    477
    +1
    58
    Is this Yamaha`s way of correcting the Cracked Heads Problems?????? This is from Yamaha`s advertisements.This is being used on the 1049 cc TR-1 Engine


    The New Thermostatic and Pressure Controlled Cooling System: Water flow through the engine is controlled by a thermostat and pressure system and is maintained by a pressure control valve.

    I first noticed Pressure control valve they are using now. What is this all about????

    This is what they say it is doing.......

    The poppits main function is to regulate the flow of water through the cooling system in conjunction with the thermostat to maintain a constant temperature in the combustion chamber. Too much water the temps drops and you run rich and and too little water and the temps rises and you run lean.

    Take Care
    CJ

    The New Thermostatic and Pressure Controlled Cooling System: Water flow through the engine is controlled by a thermostat and pressure system and is maintained by a pressure control valve.



    Last edited by cjk6119; 02-25-2020 at 03:25 PM.

  7. #27
    Pcvs are just keeping pressure on the system... hummm interesting. Guess since it not closed cooling u don’t get a constant temp so the tstat opening and closing slam the system. Im betting the pcv works in bypass around the tsat

  8. #28
    mittens's Avatar
    Join Date
    Mar 2018
    Location
    Huntsville, AL
    Posts
    617
    +1
    60
    Quote Originally Posted by cjk6119 View Post
    The problems with Yamaha heads cracking, is that just related to the supercharged engines or both, naturally aspirated and supercharged are having problems with their heads?

    Engines that are detonating will tend to overheat, because the boundary layer of gases gets interrupted against the cylinder head and heat gets transferred from the combustion chamber into the cylinder head. This might be from not using the correct octane level.

    You know what's interesting here is, when Honda had a ski on the market it seemed to be problem free for the most part. They did not have a pattern of heads cracking, clutches breaking down and they ran a turbo chargers on their engines, and for the most part was trouble free with that setup. It looked to be a very reliable platform to build on.

    CJ
    the Honda's did have a good set up, not for performance really. But a solid nice running reliable ski, other then a ECU.

    that being said. After yamaha has 09-13 of the super charger set up, woth clutch issues, but solid motor. I have wondered why not change to a factory turbo, but leaving most the other the same and eliminate that issue... such a solid platform. The amount to change is not huge compaired to new blower. New pump... new manifold and turbo cooling and make them even more reliable...

    that being said 14-15 timing chains ha so go figure.

  9. #29

    Join Date
    Jul 2005
    Location
    Central North Carolina
    Posts
    4,049
    +1
    598
    Here is a thought wonder what % of skis with cracked heads were used in salt water verses those that were ONLY used in freshwater? The reason I am think of this is that the salt water eats away the head casting in the cooling passages making the head thin in some places causing the head to crack over time. Tommy Jordan

  10. #30

    Join Date
    Nov 2018
    Location
    North Carolina on Jordan Lake
    Posts
    477
    +1
    58
    Quote Originally Posted by 2fast4u View Post
    The reason I am think of this is that the salt water eats away the head casting in the cooling passages making the head thin in some places causing the head to crack over time. Tommy Jordan
    1)Then the solution could be is fabricating a closed loop cooling system?
    2) Would the anodes on some of these skis need to be replaced that have high hours on them?

    CJ

Page 3 of 6 FirstFirst 12345 ... LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. SHO cracking head
    By JoeyDFZS in forum Yamaha PWC Performance (4-stroke)
    Replies: 18
    Last Post: 11-01-2018, 06:06 AM
  2. Cylinder Head Cover Cracking
    By infamous in forum Yamaha PWC Performance (4-stroke)
    Replies: 8
    Last Post: 03-28-2013, 07:22 PM
  3. Replies: 7
    Last Post: 10-21-2012, 10:39 AM
  4. Corrosion Prevention/Water Displacement?
    By Ultra250XRider in forum Kawasaki PWC Performance (4-stroke)
    Replies: 9
    Last Post: 08-15-2007, 12:28 AM
  5. LMAO PWI Tech on SC Prevention
    By Dr Len in forum Sea Doo Open Discussion
    Replies: 0
    Last Post: 05-26-2007, 07:23 AM

Posting Permissions

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