Close


Page 1 of 8 123 ... LastLast
Results 1 to 10 of 72
  1. #1
    Join Date
    Feb 2002
    Posts
    91
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    25

    Need jetting help FAST !!!!

    Ok , I have run into a problem with jetting my CR 144. I just installed a 1368 needle( Mr.Gorr's reccommendation) and reset my V-Force reed tension to the low setting .My problem is that I do not have a main jet large enough to get a good plug reading.I currently have a 180 main installed and the bike runs excellent through the whole range. I can ride aggressively for like 20 minutes and pull the plug it looks perfectly tan but not when doing a WOT plug chop(plug will be white ) I plan on going to a local race in the morning and am wondering if I can get away with running a richer ratio like 40:1 (currently 36:1). Would I risk engine damage ? Or will that even be enough to make a differance??If I recall Eric Gorr had suggested going to a 162-165 main so why Am I needing to go so large on the main Thanks again for ANY help on such a short notice.....







  2. #2
    Join Date
    Oct 2001
    Posts
    667
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    32
    first, going from 36:1 to 40:1 would be running leaner, not richer. i take it you're racing MX, so you will be at high rpms much of the time. running it leaner would not be good for the engine. going to say 32:1 ratio may not make a difference, except the plug may foul sooner. but if you are a person that keeps the bike revved out, then that could be your best bet until you can really get in and tinker with it. sorry for poor info, but it's the best i can do with what i got.




  3. #3
    Join Date
    Jul 1999
    Posts
    22,170
    Thanks
    0
    Thanked 4 Times in 3 Posts
    Rep Power
    269
    Originally posted by crkid
    first, going from 36:1 to 40:1 would be running leaner, not richer.
    Changing the ratio from 36:1 to 40:1 would put more fuel into the chamber, but regardless it's unlikely to help the situation.

    Within the framework of the limited info you provided it sounds like the plug you are running may be a bit warm for WOT operation on your setup, or you aren't reading the plug in the correct area. Remember you can't read the main jet from the nose of the sparkplug insulator.
    Last edited by Rich Rohrich; 02-12-2008 at 05:32 PM.



    m y   s i g n a t u r e:


    "another beautiful theory beaten to death by a gang of ruthless facts..."

    - Tom Hanna (Master Metalshaper/Nitrogeezer)

  4. #4
    Join Date
    Feb 2002
    Posts
    91
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    25
    I have been using a NGK BR9EG .Should I try the BR10EG?
    I may not have access to the "EG" plugs in the morning but should be able to get the "ES" . Might that suffice for the day. Thanks .....




  5. #5
    Join Date
    Jul 1999
    Posts
    22,170
    Thanks
    0
    Thanked 4 Times in 3 Posts
    Rep Power
    269
    Originally posted by imlostagain
    I have been using a NGK BR9EG .Should I try the BR10EG?
    NO, if you are running a 9 then the plug heat range is not the issue. Reading plugs isn't a simple task so if your bike runs strong at WOT and it isn't knocking or pinging or overheating. Then fill up the tank and ride it.




  6. #6
    Join Date
    Feb 2002
    Posts
    91
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    25
    As for reading the plug...... I believe I understand where to look ( inside the plug on the ceramic)and the plug does show a nice tan color under general riding. To be honest I'm not entirely certain what a lean plug looks like . I am under the impression it is lean simply due to absence of coloring on the insulator but the electrode is clearly white during a WOT plug chop in 5th gear for 20-30 seconds . The motor was warmed up and I was riding in a slightly inclined field. Am I correct??




  7. #7
    Join Date
    Jul 1999
    Posts
    22,170
    Thanks
    0
    Thanked 4 Times in 3 Posts
    Rep Power
    269
    See the black ring at the bottom of the ceramic? That's where you have to look to read the mainjet. All you are reading higher up is the plug temperature. In the case of the pictured plug the heat range is a little too cold and could probabaly go up a step on the heat range and the mainjet is pretty close to perfect. It could go a step leaner on the mainjet without any problems.
    Attached Images Attached Images  




  8. #8
    Join Date
    Feb 2002
    Posts
    91
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    25
    OK Rich, Upon further inspection the plug does have a "slight" tan coloration further down into the plug. Can I assume the 20-30 second ride wasn't enough to get more than a "slight" tan or should I try another size richer? Is there reason for concern with the white on the electrode after a WOT plug chop ? Thanks for the great example.....All this time I was looking about a 1/4 of the way into the plug. Would the fact that my insulator is tan after a day of riding indicate the overall jetting is relatively close or does it primarily diagnose 3/4 and up throttle positions?




  9. #9
    Join Date
    Jul 1999
    Posts
    22,170
    Thanks
    0
    Thanked 4 Times in 3 Posts
    Rep Power
    269
    Originally posted by imlostagain
    .....All this time I was looking about a 1/4 of the way into the plug. Would the fact that my insulator is tan after a day of riding indicate the overall jetting is relatively close or does it primarily diagnose 3/4 and up throttle positions?
    That portion of the plug doesn't tell you anything about the mainjet or anything else about the jetting other than how the current jetting influences the relative plug temperature.

    If you can't see down to the ring at the base of the insulator (see the picture) then you aren't reading anything relevant in terms of the mainjet strength PERIOD. You can't "read" the pilot or needle setting on the plug regardless of what people tell you, so don't waste your time.

    Running the engine WOT for 20 to 30 seconds under a load (like sligthly uphill) should be enough time to produce the mixture ring at the base of the insulator but whether or not it will produce noticeable color at the nose (top) of the insulator will depend on the oil type, oil volume and the fuel you are running.




  10. #10
    Join Date
    Mar 2001
    Posts
    7,104
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    98
    imlost, use a flashlight to look down at the base of the insulator. Almost impossible to do in regular light...or without a nice lathe.



    m y   s i g n a t u r e:


    The Universe is my way, Love is my law. Peace is my shelter, Experience is my school.
    Obstacle is my lesson, Difficulty is my stimulant. Pain is my warning, Work is my blessing. Balance is my attitude, Perfection is my Destiny. -Guillermo Tolentino

Page 1 of 8 123 ... LastLast

Thread Information

Users Browsing this Thread

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

Members who have read this thread: 2

Bookmarks

Posting Permissions

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