New to Denver PWK Carp jetting

Discussion in 'Carburetor' started by R0dd, Jun 20, 2019.

  1. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    Hello everyone,

    I just moved to Denver and just bought a Keihin PWK 28mm Carb. I have a fresh top end, V force 4 reeds, new Toomey Exhaust and running topless. Anyone know what's a good place to start for jets?
     
  2. Awk08

    Awk08 Administrator Staff Member Technician

    Joined:
    Jan 30, 2009
    Messages:
    24,129
    Likes Received:
    2,130
    Trophy Points:
    175
    Occupation:
    Electrician/Contractor
    Location:
    Pa.
    this is a good one, mile high elevation will require considerably less fuel than sea level jetting.
    I'd look thru this thread and see what others are using for 28mm PWk's, maybe start there and plug chop down to adjust for your thinner air at that elevation.

    PWK 28mm @ 4000'+ elevation....
    https://www.blasterforum.com/threads/what-jets-are-you-using.28981/#post-341244

    other helpful threads:
    https://www.blasterforum.com/thread...ir-pressure-and-how-to-jet-accordingly.39872/
    https://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/
    https://www.blasterforum.com/threads/how-to-plug-chop.53237/
     
  3. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    Thanks, Im gonna be riding around 5800 ft
     
  4. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    What is the black plastic screw (idle screw?) supposed to be set at? I put in a 45 pilot and 148 main to start and plug chop (brass air screw set 2 turns out) but every time I start up the bike the RPMs sky rocket and I have to shut the bike off in fear that I'm gonna blow it up. Its got fresh gas mixed 32:1 with yamalube 2 stroke oil. Whole engine was freshly done top and bottom with all new seals and I eliminated the TORS.
     
    Last edited: Jun 26, 2019
  5. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    8,069
    Likes Received:
    736
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
  6. Awk08

    Awk08 Administrator Staff Member Technician

    Joined:
    Jan 30, 2009
    Messages:
    24,129
    Likes Received:
    2,130
    Trophy Points:
    175
    Occupation:
    Electrician/Contractor
    Location:
    Pa.
    Larry's Shee likes this.
  7. Awk08

    Awk08 Administrator Staff Member Technician

    Joined:
    Jan 30, 2009
    Messages:
    24,129
    Likes Received:
    2,130
    Trophy Points:
    175
    Occupation:
    Electrician/Contractor
    Location:
    Pa.
    the idle screw should be barely holding the slide open
    in your case turn it out more to let the slide drop as far as it can and try a restart, then slight turns until it lifts the slide for desired idle.

    make sure you have the recommended slack in your throttle cable too, and it is routed correctly from throttle to carb, the cable can hold the slide open too far also.

    I'd turn that airscrew in to 1 or 1.5 turns out to start also, until you can get it idling correctly, then do the process of tuning the airscrew for highest idle to figure out what pilot is required ....
    https://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/
     
    R0dd likes this.
  8. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    I snapped some pics of the slide on the carb, is this position why it’s idling so high? I’m new to this carb and I can’t get the slide to come down any further.
     

    Attached Files:

  9. Awk08

    Awk08 Administrator Staff Member Technician

    Joined:
    Jan 30, 2009
    Messages:
    24,129
    Likes Received:
    2,130
    Trophy Points:
    175
    Occupation:
    Electrician/Contractor
    Location:
    Pa.
    that's open like 1/3 throttle, and is why it's idling so high
    take the cable off and back the idle screw out the whole way to see if it slides down all the way
    has to be one of those 2 holding it up that high, it should be down so far you doubt it's flowing any air, but it will

    edit: is this one of those that the slide can be put in backwards ?
     
    R0dd likes this.
  10. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
     
  11. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    Taking out the cable and putting it back in helped! Thanks bro!
     
    Awk08 likes this.
  12. Awk08

    Awk08 Administrator Staff Member Technician

    Joined:
    Jan 30, 2009
    Messages:
    24,129
    Likes Received:
    2,130
    Trophy Points:
    175
    Occupation:
    Electrician/Contractor
    Location:
    Pa.
    thumbs-up.png
     
  13. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    8,069
    Likes Received:
    736
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
    Did you make sure the needle dropped down into the main jet?
     
  14. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    Now that its idling fine its doing thiso_O:

    When I hit the thumb it bogs out a bit then I’ll hit it right after and it revs fine.





     
  15. Awk08

    Awk08 Administrator Staff Member Technician

    Joined:
    Jan 30, 2009
    Messages:
    24,129
    Likes Received:
    2,130
    Trophy Points:
    175
    Occupation:
    Electrician/Contractor
    Location:
    Pa.
    Try turning the airscrew in 1/8 turns at a time to see if it clears up, if not it's likely a needle or even wrong slide # :(
    I know the 33-36 pwk's like DGH or CEL needles and a #6 slide to work correctly

    what needle is in it now ? try lowering the clip to raise the needle and feed it a little more fuel for the pilot to needle transition you're bogging at now.

    get all your info and post it here in one post ..... pilot #, airscrew turns out for highest idle, needle #, main jet #, and slide #
     
  16. R0dd

    R0dd Member

    Joined:
    Jul 23, 2017
    Messages:
    34
    Likes Received:
    3
    Trophy Points:
    39
    Gender:
    Male
    I have the stock slide and needle in there, I didn’t know I had to change them out.... I tried to turn the air screw in but then it started to idle a little too high. I’m assuming the way it’s idling now is good. At least it sounds good to me. What slide number and needle do you recommend?
     

Share This Page