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Cylinder Dropped.

Discussion in 'Technical and Troubleshooting Torque' started by Tmaguire, Jun 6, 2007.

  1. Hey everybody, a small problem with my bike, i bought a honda cbr 250 rr about a week ago and it runs but its only firing on three cylinders. I've replaced the spark plugs an checked the spark on every lead and each of them have great spark. We've had ideas that the third carby may be blocked with a bit of stuff an isn't allowing it to get any fuel. I want to replace the gaskets for the carbies but i'll wait till i get the carbies cleaned. Any other ideas would be really appreciated. Thanx everyone.

  2. Is it making compression in the cylinder?
    If you're sure its carbs whats the hold up?

    P.S. Put some detail in your profile. You'll get better help with a bit of info.
  3. money... is the hold up unfortunatly... still a couple of days till pay day. I'm sure the compression is fine. It started to run on 4 cylinders then dropped the third again... I've been told to spray some carby cleaner into the carby while its running and that should clean it out an get it running.

    I'll update with whats goin on soon.

    P.S. Thanx for the profile tip.
  4. The spray wont work if its a blocked carb. It will make the outside, and bore of the carb clean. Its more likely a blocked fuel line into the carb.

    Have u got a workshop manual. Take the carbs off, clean and check all the lines with carby cleaner and some compressed air. Clean out the carbs. Make sure that the seal between the carbs and cylinder are good and tight.

    Its not a hard job, just follow what the manual says, and try to remember what goes where.
  5. Carbies being cleaned.

    Update: I'm getting the carbies cleaned now... The fuel line into the carby is clean an free flowng. The carbies were jammed onto the cylinder head from not being looked after for years. They used crow bars to pry them off lol. I'll post again when the carbies are back from the shop and back on the bike.
  6. Not good. Take it to mechanic ASAP.
  7. hahaha, it was the mechanics that pried the carbies off with tyre leavers... They have been cleaned tuned an balanced. This weekend i am cleaning the fuel lines, fuel tank and fuel tap. My bike should be singing on tune by saturday afternoon. I'll update then too.
  8. prying carbies off with tyre levers is unfortunatly quite normal, ive done it hundreds of times and on old 4 cylinder bikes its sometimes the only way to do it, if you are very carefull not to lever off the wrong thing it doesnt harm anything. The reason for it is your rubber inlet manifolds have gone rock solid from years of exposure to extreme heat and UV light.
    Thats not even the worst part, you should try getting the carbies back on!
  9. Rubber or silicone grease and a heat gun makes short work of it.

    Regards, Andrew.
  10. All done.

    We replaced the rubber inlet manifolds as well. The bike goes in tomorrow for the carbies to be syncronized and tuned. A road worthy then will be done on it and i'll have it registered next week. Thanx for all the information, feedback and interest. Thank you. Hopefully i won't need to ask for anymore help untill i sell it :D