Adventure Motorcycle Magazine Subscribe Now

Thread: backfire

Results 1 to 9 of 9
  1. #1 backfire 
    C-Moto Noob
    Join Date
    Jul 2011
    Location
    england
    Posts
    1
    hi ive a 250 4stroke shineray was running great and has just started backfireing the other day , will start first time and tickover all day but will not rev up without bacfireineing please help its driving me mad
    Reply With Quote  
     

  2. #2 Re: backfire 
    C-Moto Guru
    Join Date
    May 2009
    Location
    Qingdao
    Posts
    282
    I also have Shineray 250 Supermoto - XY250 GY-2.
    Mine backfires only when let of the throttle, so no problem with power just a bit annoying sometimes. Not sure how to cure it.
    Reply With Quote  
     

  3. #3 Re: backfire 
    Senior C-Moto Guru MJH's Avatar
    Join Date
    May 2010
    Location
    US
    Posts
    5,702
    http://forum.motorcycle-usa.com/defa...?f=18&m=398516

    Here’s is some good dialogue on the matter….

    Backfiring is really a timing issue and the ignition being premature and backing firing through the carburetor. The other end is consider popping and is about unspent fuel igniting in the exhaust, the use of the term backfiring is or gets confused often. Backfiring through the carburetor or exhaust?
    Reply With Quote  
     

  4. #4 Re: backfire 
    C-Moto Guru
    Join Date
    May 2009
    Location
    Qingdao
    Posts
    282
    Quote Originally Posted by MJH View Post
    ...Backfiring is really a timing issue and the ignition being premature and backing firing through the carburetor. The other end is consider popping and is about unspent fuel igniting in the exhaust, the use of the term backfiring is or gets confused often. Backfiring through the carburetor or exhaust?
    Mine is popping then - Backfiring through the exhaust
    Reply With Quote  
     

  5. #5 Re: backfire 
    Senior C-Moto Guru MJH's Avatar
    Join Date
    May 2010
    Location
    US
    Posts
    5,702
    Check for a loose exhaust at the manifold….
    Reply With Quote  
     

  6. #6 Re: backfire Did you fix your problem? 
    C-Moto Noob
    Join Date
    Jan 2012
    Location
    New Zealand
    Posts
    6
    I have a similar problem with missing and backfiring with flames from exhaust. Have read so many
    possible solutions and having tried most am now utterly confused. A clear path to follow would be great
    Reply With Quote  
     

  7. #7 Re: backfire Did you fix your problem? 
    Senior C-Moto Guru Gardo's Avatar
    Join Date
    Feb 2011
    Location
    New Jersey, USA
    Posts
    939
    check your valves
    Gardo northern NJ/NYC
    CCW tha Heist tha Widow
    CCW tha Misfit (tha Wraith)
    50 State legal and Worldwide
    CCW Heist Riders
    Reply With Quote  
     

  8. #8 Re: backfire 
    C-Moto Noob
    Join Date
    Jan 2012
    Location
    New Zealand
    Posts
    6
    Yeh done that, Its driving me nuts, almost ran ok but not quite after some messing with the carb so a bit more messing now cant even get back to what it was. Just wont rev without popping and spluttering except if I give it a tiny bit of choke then popping stops?
    Reply With Quote  
     

  9. #9 Re: backfire 
    C-Moto Noob
    Join Date
    Jan 2012
    Location
    New Zealand
    Posts
    6
    Sorted, even though the plug was black indicating too much fuel I drilled the main jet out bigger and it now runs fine, I also increased the size of the other jet but only one size. I have had this problem before and it is a pain because it can be any number of things, loose connections, faulty plug, faulty coil. My policy now will be to start with the wiring and replace the battery leads with thicker ones then check through, then do the carb and plug.
    Reply With Quote  
     

Bookmarks
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
  •