Back cylinder not working, PLEASE HELP!

Discussion in 'Sportster Models' started by BillMull, Jul 14, 2011.

  1. BillMull

    BillMull Banned

    71
    0
    2
    1996 Sportster 1200 Custom with factory Screaming Eagle Carb (Kehin). Im going to be very detailed as possible so I can maybe get the help im looking for. One evening I had rode my bike and it was riding fine. I let it cool down all the way for several hours. I then cleaned the bike. I used a rag and sprayed H-D cleaner on the rag and wiped it down. I stored it in my garage. The next day I got up and left on the bike and shortly after starting it, it started missing and acting up and sounding very strange. I came back and started checking things. I had put new plugs in the bike approx 2 months ago. I went ahead and stopped and got new plugs and put them in. Nothing changed! I looked at the old plugs, they appeared normal, if anything maybe a little lean. As we all know you have two spark plug wires, one longer than the other. One for the front cylinder and one for the back (which is the longest plug wire). I started the bike and pulled the plug on the front cylinder and the bike died. Started it back up and pulled the plug on the back and it ran. I put the long wire (goes on the back cylinder) on the front and it ran. I rotated the plug wires on the coil pack also. Same results as earlier. I emptied the float bowl and still same problem. I can however keep the back cylinder running if i keep the choke pulled though. When its idling it sounds sick and when I give it gas and rev it up it seems to kick the back cylinder in. Im lost in words for what to do....Please help if you may know whats going on!!!! Thanks so much!!
     
  2. glider

    glider Veteran Member

    25,464
    108
    44
    It sounds like you may have an intake leak effecting the rear cylinder if the choke helps to keep it running. The added fuel will help overcome the lean mixture caused by the leak.

    Harley Davidson Community
     
    Last edited: Jul 16, 2011
  3. wilks3

    wilks3 Junior Member

    623
    0
    1
    Check the compression on both cylinders. Sounds like the back cylinder is losing compression.
     
  4. dieselguy65

    dieselguy65 Account Removed

    79
    0
    1
    intake leak, almost surely
     
  5. BillMull

    BillMull Banned

    71
    0
    2
    Is changing the intake seal pretty easy to do....I can check my intake seal by using carb/choke cleaner, right? Is there chances it being the coil not producing the right amount of OHMS to the back cylinder? Me revving it up helps to make the back cylinder to start to operate...is that what is giving you guys the impression it could be the compression on the back cylinder? Im just curious what I mentioned is making you all to think its the compression...Im wanting to know just for learning purposes and to have knowledge for the future. Thanks guys for the input! Nothing like the gratitude and compassion of other Harley riders!
     
  6. BillMull

    BillMull Banned

    71
    0
    2
    Also guys, when I did the plug change to new ones and ran it and checked the plug by pulling it out. The new plug looked as if it had not even used and dry. Is that any indication to anything also.
     
  7. glider

    glider Veteran Member

    25,464
    108
    44
    It substantiates that it may be lean as a result of an intake leak.
     
  8. BillMull

    BillMull Banned

    71
    0
    2
    I also forgot to mention to you all also, for the past week or so I have been adjusting the carb mixture screws and idle screws to try to get the carb adjusted better. Then this happens. I didnt know if you guys need to know this just in case I had done something to it to mess it up...
     
  9. glider

    glider Veteran Member

    25,464
    108
    44
  10. BillMull

    BillMull Banned

    71
    0
    2
    Hey Glider, can I test to see if I have a leak around my intake by using carb cleaner by spraying it around it while its running. If the bike responds to it, that means I have a leak? Is that correct? Is there any chance the problem is the coil?