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Erratic Idle/Engine Flutter

Discussion in 'Technical and Troubleshooting Torque' started by VCM, Mar 29, 2008.

  1. Gave the Hornet a service yesterday. Oil, filters, plugs, clean and relube chain, cables etc...
    I've noticed the Hornet has been idling more erratic, esp when cold, lately.
    Now there seems to be running a little rich and has developed a slight engine flutter. In my exp with engines, I'd say either the carbs need looking at/synch, or the valve clearnces need resetting ( smell of unburnt fuel at exhaust with a slight 'coolness' is felt every few cycles ).
    Unfortunately there are no service manuals ( in english ) for the hornet.
    I am assuming the power plant is the same as the CBR250RR, which means the valve clearances are set by shims. ( not sure if most bikes do these days .. I am not a motorcycle mechanic ).
    If this is correct, then I should set clearances as per a CBR .. right? :? Can anyone shed a little light here ?
    Not sure how difficult a job it's gonna be, easy enough to do a DOHC out of a car, on the bench .. but bikes ???

  2. i thought the MC22 had hydraulic tappets? carb balance first i would think.
  3. there is an english version of the cbr250 manual in cyberspace (try torrents).

    The engine uses shim under bucket valve adjustment and does not have hydraulic tappets. It does have a gear driven head though.

    Assuming this is the same engine as the hornet, the hornet will probably have carbs with a smaller throat diameter, but most things should be the same.

    The full sequence of operations is:

    1. clean up the carbs, make sure there aren't any pinholes in rubber diaphragms and so forth.
    2. check valve clearance.
    3. Synchronise the carbs.

    A carb synch won't help if you have a tight valve, nor will it achieve anything if one is running far too lean because it is gummed up etc.

    Whether or not you want to put this effort into it is up to you.

    The final thing is to check the spark plugs and the leads. When they get old you can find similar irregular behaviour.
  4. Dude, just take it to a mechanic
  5. Thx Guys .. I'll have the carbs checked/synchronized...( I don't have the equipment for that so I guess it's off to the bike shop, failing that I gues I'll have to look at clearances.

    PP: Vlave clearances are something I won't pay someone to do.
    If I can't do that myself .. I may as well call it quits and ride a bicycle :p
  6. if you can do valve clearances, you'd find stripping the carbs to be a snap too. It isn't difficult - just lay out all the parts in order so you know what goes where. And since the tank and airbox will be coming off anyway...
  7. You're probably right bonox .. I just got that fear of the unknown , this thing dont have 4 wheels :p
    I'd have to borrow one of those mercury gauges to to the synch .. which I dont have. :oops:
  8. a quick word of advice

    tell the mechanic what the problem is and let them solve it. Don't tell him you want the carbs synchronised and then complain when/if the problem is still there.

    Above all, have them call you before they commit to any work.