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f1nxlife Feb 27, 2020

  1. f1nxlife

    f1nxlife Supporting Member

    Well, I have been running the 900 for the last 2 days, 3 tanks of gas, used sea foam and marvel mystery oil to try and clear out the carbs..The bike is running great above 3500 revs, I forgot about the fantastic engine growl that this 900 makes throughout the rev range. I am getting sometimes backfire on deceleration which has never happened before. I am going to have the shop sync the carbs, has not been done in over 10 years. I also want to change the plugs, I hope that improves things so I dont have to do a complete carb rebuild. I had a new front Bridgestone spitfire tire installed today, to go with th brand new MIchelen rear I had put on a while back. I am going to run this last tank of gas with the sea foam additive. Im hoping the shop that did my GPz can do the plugs and sync next week while I wait, Im now friends with the owner, and I buy lunch for him and his guys about once a month, Moto Classics in Inglewood California. I will also get the 1000 a fresh oil change and tank of gas and see how it runs after sitting for a while.

  2. 87kawzl

    87kawzl Supporting Member

    Popping on deceleration may indicate an exhaust leak. I always adjust the valves before a sync to make sure each cylinder is operating properly. You should really drain the carbs if they are going to sit for a month or longer to help prevent passages from gumming up.
    f1nxlife likes this.
  3. Supereli

    Supereli Member

    Hi Brett,
    a little setback does no harm!
    Synchronization is a must, valve games are OK ?! At zero play, a valve is slightly open and lets fuel into the exhaust gas, where it ignites.
    And then hit the speed limiter!

    I always leave the fuel in on all bikes, over idle times with additive, always worked.
    f1nxlife likes this.
  4. madmanncr500

    madmanncr500 Senior Member

    I would have Rick rebuild your carbs, sounds to me like your low speed jets are glogged. The carbs on these ZL's are very finicky and can be jacked up if a person dosnt know these carbs, a person may know how to rebuild carbs, and think they all are the same...for some reason the ZL carbs are unique to these bikes....
    f1nxlife likes this.
  5. Ed

    Ed Well-Known Member

    I agree. It's a waste of time syncing if it ain't running right. And running chemicals thru the carbs to clean them is wishful thinking at best.
    f1nxlife likes this.
  6. lowlife

    lowlife ZL Mad Scientist/ Supporting member Technical Author Supporting Member

    You still have actual gas in Cali? Huh I was thinking everything ran off sunshine and roses....

    You have something else going on if it runs like crap below 3500. I agree with all the possible diagnoses above. A carb synch wont help it run if it aint right. If you were closer Id teach you to do the carbs and synch. Take it to the shop and get their opinion first. Sea foam is some pretty good snake oil but a miracle worker it is not. Do you have ethanol in Cali fuel?
  7. f1nxlife

    f1nxlife Supporting Member

    Yes they put that ethanol crap in the gas, thank you guys for the info, I think I will go for the valve adjustment and carbs sync, and also check the exhaust
  8. Ed

    Ed Well-Known Member

    I wouldn't just sync the carbs. Send them out to be cleaned and synced at the same time. You've indicated that they've probably got at least partially clogged jets. Not good to keep running it that way.

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