Page 1 of 2 1 2 LastLast
Results 1 to 10 of 11
  1. #1

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597

    max rpms with stock cams

    Hi,

    I'd like ask you about maximum rpms with any stock cams, w/o faults.

    thanks


  2. #2
    R88ory RXP's Avatar
    Join Date
    Feb 2008
    Location
    Kent, England
    Posts
    2,737
    +1
    46
    Quote Originally Posted by repsol View Post
    Hi,

    I'd like ask you about maximum rpms with any stock cams, w/o faults.

    thanks
    There are many race engines flying around with stock cams at 9000+ rpm, you only need lightwieght so the engine revs faster.

    Obviosly the valvetrain needs to be looked at to rev those sort of RPMs, you will need light valves and retainers and uprated springs ect ect. R88

  3. #3
    home of the dislexic fingers breon's Avatar
    Join Date
    Aug 2007
    Location
    port st lucie fl
    Posts
    3,471
    boats may be running stock cams.. running on stock cams at 9000 rpm may not make the most power..the head is where all the power is made...ok boost has alot to do with it too but you know what i am saying..

    cams are made to make power in certain rpm range..if you run the ski beyond the rpm the cam is made for the engine it wont make as much power as it could..the fact that we can adjust our cams a few degrees..allows us to change the eficiant rpm band the cam works in a few hundred rpm ... it still isnt going to be as good as a cam designed for that rpm range..

    stock cam is made to run 8100

    4224 cam is made to run 8600 .

    i assume the other rotax cam 6??? is made to run 8800
    i assume the same goes for the rapid cams abc

  4. #4
    speedskixp's Avatar
    Join Date
    Feb 2008
    Location
    venice fl.
    Posts
    8,117
    +1
    120
    Quote Originally Posted by breon View Post
    boats may be running stock cams.. running on stock cams at 9000 rpm may not make the most power..

    cams are made to make power in certain rpm range..if you run the ski beyond the rpm the cam is made for the engine it wont make as much power as it could..the fact that we can adjust our cams a few degrees..allows us to change the eficiant rpm band the cam works in... a little but it sitll isnt going to be as good as a cam designed for that rpm range..
    +1 good info.

  5. #5

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    thanks all,

    I think about, because I have RR4224 and 05 stock cam ( with lightweight mod ) and I know RR cam get more +1mm lift than stock, and any times with this cam I was problems that touch a pistons, but I was installed riva springs kit and light valves.

  6. #6
    Quote Originally Posted by repsol View Post
    thanks all,

    I think about, because I have RR4224 and 05 stock cam ( with lightweight mod ) and I know RR cam get more +1mm lift than stock, and any times with this cam I was problems that touch a pistons, but I was installed riva springs kit and light valves.
    Do you have oversize valves?

  7. #7

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    no, I have stock size lights

    thanks

  8. #8
    home of the dislexic fingers breon's Avatar
    Join Date
    Aug 2007
    Location
    port st lucie fl
    Posts
    3,471
    the rotax cam ramps different as well and it is supposed to help with float...

  9. #9

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    Quote Originally Posted by breon View Post
    the rotax cam ramps different as well and it is supposed to help with float...
    maybe, but when I tried RR cam, many times touch my pistons a bit. This is a +1 mm lift i think.

  10. #10
    Here is the spec on the 4224 cam, which I have run since 2005. I checked it on my ski with the cam and crank locked. I also have the head decked .030. I have run the cam straight up and for the last two years have run it 3 degrees advanced. Never had a problem with pistons hitting valves. I don't know the lift on the stock cam. Advanced 3 degrees gives the ski more down low and in the midrange.

    Mark
    Attached Files Attached Files

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. Max RPM on stock 2014 310R
    By cdarling12 in forum Kawasaki PWC Performance (4-stroke)
    Replies: 113
    Last Post: 04-25-2015, 06:42 AM
  2. VTech Tune - What is Max RPM for stock fuel system
    By TheElite0ne in forum 4-Tec Performance
    Replies: 16
    Last Post: 04-18-2013, 12:14 PM
  3. max hp with stock fuel pump
    By skidoochris in forum 4-Tec Performance
    Replies: 1
    Last Post: 03-24-2012, 09:21 AM
  4. problem getting max rpm with rr ecu
    By masta2000 in forum 4-Tec Performance
    Replies: 4
    Last Post: 06-18-2010, 09:28 PM
  5. Max Boost with stock headbolts vs ARP's
    By Hecyan in forum 4-Tec Performance
    Replies: 1
    Last Post: 11-10-2008, 11:19 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
  •