5th gen running rough

Discussion in 'Mechanics Garage' started by dutchdog1, Jan 29, 2010.

  1. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    my 1998 vfr 800 has started running rough...almost like bad gas.....i started running premium but it hasnt helped....this started when the weather cooled down n seems to b slowly getting worse....sometimes wont accelerate hard etc...any help would b appreciated
     
  2. ZEN biker

    ZEN biker New Member

    Joined:
    Apr 1, 2009
    Messages:
    767
    Likes Received:
    2
    Trophy Points:
    0
    Location:
    Assiniboia, SK
    have you pulled your plugs to see if their fouled? I recently had a similar symptom and one plug was fouled. other thing to check is your fuel filter, air filter. if there good then you will need some tools to look deeper in, eg. fuel pressure, sensor diagnostics ect. Tell us what you have done and what the results where.
     
  3. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    havent done anything yet.....not very mechanical so wanted to check the forum first.....i hv a shop manual but it looked complicated to ck fuel filter....can it be ckd wout removing tank?
     
  4. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    i cked air filter wn i changed oil and it seemed fine
     
  5. vfrcapn

    vfrcapn Member

    Country:
    United States
    Joined:
    Sep 9, 2004
    Messages:
    1,405
    Likes Received:
    2
    Trophy Points:
    53
    Location:
    Grass Valley, CA
    Map
    Check all the vacuum lines under the tank and to the throttle bodies, maybe one came loose when you checked the air filter.

    And our CA winter gas does suck, my gas mileage drops 5-6 mpg every year when they start selling that stuff.
     
  6. TOE CUTTER

    TOE CUTTER Mullet Man

    Country:
    United States
    Joined:
    Nov 30, 2008
    Messages:
    6,731
    Likes Received:
    85
    Trophy Points:
    78
    Location:
    Sacramento
    Map
    I take it that the FI light is not on or flashing?How many miles, any work done lately,when and how did it start,history?
     
  7. steven113

    steven113 New Member

    Joined:
    Sep 15, 2008
    Messages:
    660
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Pensacola FL
    Give your battery a full charge and change the spark plugs. low voltage from a bad battery can foul the plugs causing the same symptoms you mentioned. No need to run premium gas in your VFR..
     
  8. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    about 6 months ago i installed hvy duty rectifier n hvy duty harness......about 6 weeks ago changed oil ....filter n cked air filter.......it had started running rough before that but not bad.....wn it got cold.....it started running rough.....hard to start even w choke.......the run pretty well one stoplight then act like running out of gas at next.....but even wn fairly good it wld hv lag when hit the throttle and struggle to accelerate........thanks for advice n ill ck vacum hoses
     
  9. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    i replaced the battery wn i replaced rectifier n havent had any charging issues since........wn its hard to start it cranks strongly for a long time its just slow to fire up.....thanks guys.......spark plugs n vacum lines today *crosses fingers*
     
  10. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    stupid question.....i pulled spark plug caps......cant find spark plugs.....r thy waaaaay deep in the hole....due to angle i cant see to bottom.....caps r like six inches long.....never changed plugs on bike b4....only cars
     
  11. vfrcapn

    vfrcapn Member

    Country:
    United States
    Joined:
    Sep 9, 2004
    Messages:
    1,405
    Likes Received:
    2
    Trophy Points:
    53
    Location:
    Grass Valley, CA
    Map
    Yes, they're way down. 18mm socket if I remember correctly, you'll need an extension obviously.
     
  12. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    cool....thank u
     
  13. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    well i put new plugs in n checked that all the lines r connected n in good shape......still boggin wn i hit the throttle hard....if i do it 2-3 times then its good but keeps doin the same thing.....anything else i can do before i start pullin the tank n chkn the fuel filter pump etc
     
  14. steven113

    steven113 New Member

    Joined:
    Sep 15, 2008
    Messages:
    660
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Pensacola FL
    The fuel filter and pump are both in the tank. Is there rust in the tank?
     
  15. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    no rest in tank.......is that how i can tell if the filter is clogged.......its the fuel injected model.....wld fi cleaner b a possibility?
     
  16. steven113

    steven113 New Member

    Joined:
    Sep 15, 2008
    Messages:
    660
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Pensacola FL
    rust would be an indicator of such a problem and it is unlikely without it that your filter would be clogged. How many miles are on your bike? My experience with FI cleaner is that it is a matienece kind of thing, if it is infact a clogged injector it may or may not help. Have you tested the compression across the cylinders? It is quite possible your fuel pump is not making the pressure that it needs to for the system to work proporly or that the fuel pressure regulator is going out also. When you pulled your plugs what did they look like? Were they wet/burnt/smelled like gas?
     
  17. dutchdog1

    dutchdog1 New Member

    Joined:
    Feb 2, 2009
    Messages:
    18
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fresno
    Map
    thy looked bad......one white......other three blk
     
  18. TOE CUTTER

    TOE CUTTER Mullet Man

    Country:
    United States
    Joined:
    Nov 30, 2008
    Messages:
    6,731
    Likes Received:
    85
    Trophy Points:
    78
    Location:
    Sacramento
    Map
    First gen 6 I ever worked in would load up and run rough until it was rung out and would run fine for a very short period of time and then would run rough again. The injectors were leaking fuel and if you turned on the ignition without starting you could see fuel dripping from the injectors.This bike sat for a long period of time and I always assumed it was water damge to the injectors.A new set fixed it right up.
     
  19. steven113

    steven113 New Member

    Joined:
    Sep 15, 2008
    Messages:
    660
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Pensacola FL
    When I first bought my 5th gen it had been sitting unused in a shed for almost 10 years without the fuel being drained. All of the injectors were stuck, I was able to free them by soaking the entire throttle body in denatured alcohol in a 5gallon bucket for a week and have had no issues with them since. Worth a try IMO before spending big $ on new injectors. Note... if you do try this it is important to use denatured alcohol because it will not damage rubber or plastic parts like acetone or other solvents might.
     
  20. 78EDGES

    78EDGES New Member

    Joined:
    May 25, 2009
    Messages:
    72
    Likes Received:
    0
    Trophy Points:
    0
    What rpm range is it running rough @ ? and does it do this @ idle?
     
Related Topics

Share This Page