1. After 20+ years it's time to pass the torch. If you are interested in acquiring this forum please contact support@cv-performance.com for details. Any spam will be reported and blocked.
  2. Welcome to Bike Talk, a forum for all bikers and motorcycle enthusiasts. If you are new to Bike Talk, be sure to register for free and join the conversation.

    There's always someone around willing to help out with questions or give a friendly wave back. All Harley and metric riders are welcome.
Bike Talk Motorcycle Forum is For Sale Welcome to Bike Talk

1990 FXR won't idle

Discussion in 'Motorcycle Tech Talk' started by Rumrunner, Dec 6, 2015.

Page 1 of 2
  1. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    ive done all the recommended trouble shooting tips, bike sat for several years. Cleaned out all the old gas in tank and carb. Any other suggestion?.
    Rumrunner, Dec 6, 2015
    #1
  3. bambidee

    bambidee Active Member

    Joined:
    Jun 12, 2011
    Messages:
    453
    Likes Received:
    74
    Location:
    upstate n/y
    Welcome, guessing AZ is mostly hot and low humidity. You checked for vac leaks? When you say cleaned out tank and carb how bad was the fuel? Did you remove carb and bowl, clean with a product like Gumout or Dragonfire?
    bambidee, Dec 6, 2015
    #2
  4. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    bambidee, I did put in good premium gas a little STP, compleltly went thru the carb, and put it back together correctly no changes. Did the propane vacuum leak test I'm stumped. What's strange is it idles great when I have the choke pulled and it runs at higher RPM with the choke off. It pops and sputters a little I'm assuming that's cause the air cleaner and stuff is off???
    Thanks for the reply
    Rumrunner, Dec 6, 2015
    #3
  5. bambidee

    bambidee Active Member

    Joined:
    Jun 12, 2011
    Messages:
    453
    Likes Received:
    74
    Location:
    upstate n/y
    A higher idle suggests a vac leak or the idle stop was turned up somewhere in the process to keep it running, pulling choke on also indicates lean. How did the carb look when you pulled apart for varnish? Silly question, is carb a Keihin? My best guess is recheck for vac leak and if you do not find anything pull the carb again.
    bambidee, Dec 6, 2015
    #4
  6. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    It's a HD CV carb I'll check the va leaks again and adjustb
    I

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 6, 2015
    #5
  7. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    Adjust the mix screw thank you

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 6, 2015
    #6
  8. bambidee

    bambidee Active Member

    Joined:
    Jun 12, 2011
    Messages:
    453
    Likes Received:
    74
    Location:
    upstate n/y
    where is the pilot adjustment? should be somewhere between 2 1/4 to 2 3/4 most of the time if the comb is correct, just be very gentle when bottoming it out.
    bambidee, Dec 6, 2015
    #7
  9. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    The idle mix is located behind the carb float tank, the pilot is located inside the carb float tank about the middle been using CV performance web site and parts. I feel confident I put it back correctly. There hasn't been any new symptoms since I started I think I still have the original problem

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 6, 2015
    #8
  10. Marc1340

    Marc1340 Active Member

    Joined:
    Dec 6, 2014
    Messages:
    154
    Likes Received:
    15
    Location:
    Nordeste Sao Miguel Azores
    check the float level, maybe to high or low. check to see if the float tab has not been bent or bunged up
    Marc1340, Dec 7, 2015
    #9
  11. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    The bowl has always been full when I've taken it off, I'll re check that

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 7, 2015
    #10
    Marc1340 likes this.
  12. Lucifer

    Lucifer Well-Known Member

    Joined:
    Mar 20, 2008
    Messages:
    3,861
    Likes Received:
    102
    Location:
    Cape Breton NS,Canada
    Check the hose from the carb to VOES switch for cracks/leaks
    Lucifer, Dec 7, 2015
    #11
    Marc1340 likes this.
  13. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    What does the VOES switch do?

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 9, 2015
    #12
  14. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    The VOES is a Vacuum Operated Electrical Switch that adds or pulls timing based on vacuum load. As you roll on the throttle, you are opening the slide of the carb introducing more air and vacuum into the engine. As that happens, the VOES sends a sigle to the ignition to advance your timing. Same thing happens when you close your thtottle, with less vacuum, the switch sends a signal to retard your timing. If the hose is cracked, it won't send the proper signal.

    Also, do you have a vacuum operated fuel valve or is it gravity fed?
    JohnnyBiker, Dec 10, 2015
    #13
  15. Lucifer

    Lucifer Well-Known Member

    Joined:
    Mar 20, 2008
    Messages:
    3,861
    Likes Received:
    102
    Location:
    Cape Breton NS,Canada
    Lucifer, Dec 10, 2015
    #14
  16. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    It's gravity fed,

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 10, 2015
    #15
  17. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    Ok, when is the last time you have had the fuel valve off and cleaned it?
    JohnnyBiker, Dec 10, 2015
    #16
  18. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    Do you mean the main fuel valve, that is working and there is a glass type filter below you can see there is fuel preset the bike idles when the choke is pulled, when you release the choke it dies like you hit the kill switch. After it warms up you can keep the bike running with a slight twist of the throttle, when you release the throttle it dies immediately. Really has me stumped? Thank you for the repls s

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 10, 2015
    #17
  19. JohnnyBiker

    JohnnyBiker Well-Known Member

    Joined:
    Mar 25, 2010
    Messages:
    9,568
    Likes Received:
    205
    Location:
    Minnesota
    Nose cone ignition?
    JohnnyBiker, Dec 10, 2015
    #18
  20. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    Since it shuts off when you push choke in, or release throttle then it's not getting fuel at idle, or "enough" fuel at idle.

    Reasons for this are typically,

    a) too much air for the fuel supplied - ie vacuum leak, carb not seated in manifold, manifold leak, broken or cracked vac line,

    b) not enough fuel - clogged jet, clogged tube, improper float level, float closing off and blocking fuel flow to carb bowl.


    You said you are running a gravity petcock, so the vac port on the top of the carb should be blocked off, typically with a cap, if that cap is worn, cracked or missing, replace it.

    If the intake manifold seals are old and the bike hasn't run in a while it might be a good idea to replace the old ones, they get dry and hard and don't seal, same with the rubber gasket to carb.

    As to fuel, check that the jets are improperly installed, that they are clear and free
    of schmutz, check float level, make sure float isn't blocking off fuel flow to the carb

    remove top, check diaphragm, make sure it's not torn and be careful not to rip.
    hotroadking, Dec 10, 2015
    #19
    Marc1340 likes this.
  21. Rumrunner

    Rumrunner Member

    Joined:
    Dec 5, 2015
    Messages:
    13
    Likes Received:
    2
    Location:
    San Tan Valley, AZ
    I'm not familiar with the nose cone ignition. It's a very stock 1990 FXR police special.

    Sent from my XT1080 using Tapatalk
    Rumrunner, Dec 10, 2015
    #20
Page 1 of 2

Share This Page

XenPorta © Jason Axelrod from 8WAYRUN.COM