990 valve clearance question.

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by coyo, Mar 2, 2013.

  1. coyo

    coyo Adventurer

    Joined:
    May 7, 2012
    Oddometer:
    15
    I have an 08 KTM Superduke with the 990 LC8 and in checking my valve clearances today;

    Rear cylinder exhausts were tighter feeling than intakes however in all cases go/no go had all max feelers fitting (.152mm intake and .305mm exhaust) where the next size up wouldn't go (.178mm and .330mm respectively). Il leave them alone

    Front cylinder exhaust were a different story. The high side of the exhaust (.305mm) was tough going in. The intakes saw one valve OK however the other had the low side go in (.102mm) however I couldn't get the mid-range (.127mm). Is this still good for the range?
    #1
  2. coyo

    coyo Adventurer

    Joined:
    May 7, 2012
    Oddometer:
    15
    Anyone?
    #2
  3. Katoom72

    Katoom72 Been here awhile

    Joined:
    Jun 3, 2012
    Oddometer:
    952
    Location:
    Belgium
    Your description is rather confusing to me. If i get things correct:

    The intakes are becoming tight as with the exhausts u are at the outer range of the clearance. They both are at the edge of the clearance.

    I'd reset em to the middle of the spec since you're in there already.

    Again, if i get things correct that is.
    #3
  4. coyo

    coyo Adventurer

    Joined:
    May 7, 2012
    Oddometer:
    15
    In being overly paranoid about this and wanting to clearly describe what I've got here (and researching extensively what "slight drag" is supposed to be for using feeler gauges), I think I can more accurately say what clearances I've got (all in mm's and the 2nd # is the size of the next up that won't fit);

    Front
    Exhaust
    L .279/.305 R .279/.305
    Intake
    L .152/.178 R .102/.127 (the left one was a bit rough going in)

    Rear
    Intake
    L .152/.178 R .152/.178
    Exhaust
    L .279/.305 R .279/.305 (both were rough going in however some of that could have been due to the fact that the feeler has to go under the cam, over the head, and then under the frame spar)

    So 3 of my intakes appear to be .002mm over... if I'm accurately using "slight drag".

    Opinions?

    #4
  5. Katoom72

    Katoom72 Been here awhile

    Joined:
    Jun 3, 2012
    Oddometer:
    952
    Location:
    Belgium
    So the clearences sit at the edge a bit. It's up to you, reset em to the mid of the range or bolt things back up and do it the next interval.

    No need to worry, in my opinion. :1drink

    What is the mileage/km count?
    #5
  6. coyo

    coyo Adventurer

    Joined:
    May 7, 2012
    Oddometer:
    15
    18,900 kms.

    #6
  7. coyo

    coyo Adventurer

    Joined:
    May 7, 2012
    Oddometer:
    15
    You'll have a laugh on me and my paranoia however I just wasn't happy with;
    - my interpretation of "slight drag", and
    - the angles required to get the feelers under the lobes causing the feelers to bend or rub on the head, or both
    so I tried bending my feelers to assist them getting into position... and broke a couple.

    So I went looking for offset feelers and found many... online. None in stock anywhere.

    So I bought a new set, took them apart, and hammered a bend with a hammer and screwdriver into the ones I needed. This made things MUCH easier to get into position and get a better idea of the true clearance. I think I was using too much pressure to get the feelers in place which forced them under the lobes at the same time.

    New numbers (in mm);

    Front
    Exhaust
    L .28 R .28
    Intake
    L .13 R .08

    Rear
    Intake
    L .13 R .15
    Exhaust
    L .28 R .28

    With that one front intake valve now being below spec, I'll be adjusting it. I don't think I'll bother with the one rear intake.

    Thanks for all your help. Now I have to buy the crank lock bolt so I can proceed to the next step...
    #7
  8. Katoom72

    Katoom72 Been here awhile

    Joined:
    Jun 3, 2012
    Oddometer:
    952
    Location:
    Belgium
    Paranoia can be good sometimes. :D
    #8