Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Fuel issue?

Discussion in 'Technical and Troubleshooting Torque' started by cmarico, Aug 31, 2012.

  1. Gday there.

    This morning my 2000 ZZR250 lost a bit of power, and started to sound quite throaty while on the freeway. If I gave it throttle it would respond and come good, but just holding throttle it would lose power and sound strange. This lasted for about 5 minutes, and then seemed fine for another 5 until I got to work.

    Now, before I left I filled up at BP with 91ron unleaded. The top of the fuel tank was wet - was wondering if maybe some water got in and contaminated the fuel - and that was the result? Perhaps a spark plug is on it's way out? Maybe the carby got stuck momentarily?

    I'm not really sure, but I know I don't want this to happen again so just chasing avenue's to look at over the weekend.
  2. A bike that clears with more revs is generally indicative on dirt under a float needle. These things FI or carbie?

    Giving it some berries can clear it, particularly if you catch it early. It appears that is what you've done here.

    So the question is, does it have a fuel filter and when was it last changed?
  3. Thanks for the reply ibast. They're a carbie.

    I'm not too sure whether it's got a fuel filter or if it's been changed recently - so I guess i'll have a look at that too, only got the bike a week or two ago - and planned on going through it this weekend.
  4. Clean plugs
  5. Thanks guys. Gives me a starting point. I'll do the plugs and an oil/oil filter/air filter change tomorrow. Also was reading that these don't come with a fuel filter - probably worth putting one on.

    If there is gunk in the carby, will spraying some carby cleaner through the intake work or should I disassemble the whole thing? I don't have a vac tool to synchronize the carbies, thats my concern with disassembling them to clean them.
  6. Unless it happens again I won't worry too much. I was probably just a spec of dirt which stopped the needle seating properly and it's gone now.

    Spraying carbie cleaner in the throats of the carbies won't solve this, but it will clean gum out of other bits, so it's not a bad thing to do. Don't spray so much that it washes down the cylinder walls.

    You can make your own u-tube manometer for balancing these carbies. The interweb is your friend. I do advise getting some cheap needle valves from an aquarium to dampen out the suction, otherwise you will struggle to keep the fluid in the tube.

    If the problem happens again, you maybe be able to clean it on the bike. The area you need to clean is inside the float bowls. Remove the bowls and spray around in there. Put a rag over the gearbox just in case the needle falls out. Also you will spill petrol, so make sure the bike is cold and there is plenty of ventilation.
  7. No worries, thanks heaps guys :)
  8. Had my 250 do the same, lose power for a bit and then get it back, couple times ended up on the side of the road.
    Was always on a hot day and making the bike work hard for 100kph.
    Same symptoms - losing power under throttle, noisy throaty sound (throttle was wide open trying to get it to go resulting in that noise), and generally just dying - good description i know :D.

    Each time it was vapour lock for me. Id crack the tank and give it 5min to cool (seemed to need this step, even though the engine itself wasnt overheating), few extra turns on the starter and we were off again.

    Just something to keep in mind in case it persists or results in you being on the side of the road - give the above a try before calling the tow truck.
  9. Definitely. Easiest option is to try the auto stores for a small inline fuel filter, making sure it's the right size for the fuel hose on your bike (you'll need to measure the inner diameter). Should only set you back a couple of bucks, so worth getting two (always pays to carry a spare on long trips).

    Then it's just a simple case of cutting the hose at a suitable point, and attaching the cut ends to the filter.
  10. Agree, they have a little white 'mesh' thingy that sits inside the fuel pipe, just where it goes into the carby. Pull the pipe and you will see the mesh.
    I took it off and got a small carby fuel filter (think it was gravity fed - not sure if it HAS to be but i think so...).

    Also, make sure you get one with at least one end being a 90 degree. Straight through cant make the bend from the fuel tap to the carby inlet.
  11. Changed plugs, air filter, oil an oil filter. Issue still persists though is intermittent. Was on freeway, happened again. Gave it a few hard revs but was still playing up. Pulled over, cracked the tank, fired her up again. Still playing up. Few more hard revs, seemed to clear. 500m later same issue, begin slowing for a turn, backfires (loud pop). Hard rev and she was fine the next 5 min when I got home.

    Any other ideas at this ppint? If it was out of tune wouldn't it e always out of tune? Maybe a coil pack on its way out? Or still with the iffy fuel? Also found a fuel filter on it, looked clean so haven't replaced it yet. I'm rater confused.
  12. Is it the little mesh thing or a proper filter? In either case it may not help the problem, but may help prevent more later so worth replacing for the few bucks they are.

    Electrical is possible, but i dont know much about it. It sounds like its being starved of fuel. What fuel are you running in it?

    I had a carby clean when i had the zzr, but while it made a world of difference to the feel of the bike (was running rough), i still suffered the above occasionally.
  13. Proper plastic filter. I'll change that tomorrow night. This tank is 91 octane, normally run that or 95. When you say carby clean, did you dosassemble the carby or just spray the cleaner stuff through it?
  14. Since carbies scare me more than tinkering with FI (which i seem to do without a thought), i had my mech do it.
    He stripped it out, took several parts off, and soaked them overnight.
    Used an ultrasonic cleaner on some parts.
  15. I've cleaned carbies before, though I was ver drunk and there was only one so no need to sync them. Hmmm. I hate intermittent issues, if it was happening all the time would be much easier to narrow down.
  16. Will be getting the carbies done this weekend - after the issue went away completely last week, then reared it's head again today. The issue has only ever happened on the freeway - never on hills rides. Any chance there's water in the fuel (washed the bike yesterday - would that cause this kind of issue)? Had to pull off the freeway today, as it wouldn't hold speed, nor idle. A couple of minutes later it was fine again - I did open the fuel tank (someone mentioned vapour lock earlier) - could that have anything to do with it. I'm really at a loss now - I've spoken to a couple of mechanics and being an intermittant issue they all say it will be difficult to determine :/