Fuel Tank breathers

Discussion in 'Maintenance' started by Darren lee, Dec 20, 2018.

  1. Darren lee

    Darren lee New Member

    Joined:
    Sep 2, 2018
    Messages:
    12
    Likes Received:
    2
    On the CBR 1000 R5 bike I brought recently I,ve noticed the large and small fuel tank breather are going nowhere and cut off short, is there any issue with this. I only ask because I,ve had the bike on the dyno recently for setting up and they said fuel was leaking from somewhere. I replaced the fuel pump recently but cannot see any signs of leaking from that seal .
    I realise there shouldn't be fuel coming from the breathers but cant see any other issue.
     
  2. bonjo

    bonjo Active Member

    Joined:
    Aug 15, 2013
    Messages:
    1,370
    Likes Received:
    227
    I had a similar puzzle on my RR8 and established the breather on mine is a short 90 deg hose going nowwhere (not to mix up with the overflow hose)

    maybe your is the same
     
  3. Darren lee

    Darren lee New Member

    Joined:
    Sep 2, 2018
    Messages:
    12
    Likes Received:
    2
    Thanks for your reply, was yours leaking fuel at any point.
    I just cant seem to locate anywhere that fuel is leaking fron
     
  4. Muffking

    Muffking God Like

    Joined:
    Jun 30, 2012
    Messages:
    5,835
    Likes Received:
    2,831
    I can't hep you with the leak, but the breather should run down the N/S of the bike towards the belly pan area through a loop on the side stand bracket. It's an overflow from the tank in case it's over filled or the bike ends up on it's side.
     
  5. bonjo

    bonjo Active Member

    Joined:
    Aug 15, 2013
    Messages:
    1,370
    Likes Received:
    227
    I think you have someone knowladgeable about your bike on board.
    I had no problems except when I lifted the tank, I didn't notice it until when it was lowered and couldn't understand the short length of the breather hose!
    You problable have and overflow hose which should go right to the bottom of the bike to drain the excess fuel if needed. The breather on mine is connected to the fuel supply line ( I think) through some valves. I assume it allows the excessive vapor pressure to be released. TBH, I have never smelt fuel on mine.

    So yours should have a similar arrangement.

    If either tubes are blocked, kinked or cut short, then the smell can appear in the wrong place and be noticed.
    Incidently the have you checked you fuel cap seal? In case it is not doing it's job properly, letting vapor out in your face or allowing fuel to leak out of the tank when leaning or start/ stopping
     

Share This Page