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.

Bike spluttering when wrist snaps back on throttle

Discussion in 'Bling and Appearance' started by junkie750r, Aug 19, 2006.

  1. Hi all, im riding a 1985 gixxer and of late, when ever i ask for a quick response from the throttle, she just splutters.
    she can pull high revs but she has to be worked in, carbie and bike were serviced 2000 kays ago. Any-one else had this problem that can give a clue where to spend money on first before i replace engine to find out it was a lead (joke).
    she was running real sweet and could handle any quick snap of the wrist but some issue now creeping in.

    Thankyou for anyone who adds input, im extremely fresh to bikes - before last december never even thought about riding them. Im enjoying them now but mechanically clueless.
  2. Air leak somewhere perhaps?
  3. When you say the carbs were serviced 2000km's ago, what exactly did you have done?
    If the carbs were stripped down and cleaned thoroughly, and the needles in them are extremely old then the process of cleaning them may have removed the buildup on the needles that was acting as filler, so essentially now your needles may be even more worn than they were previously!
  4. +1 on the air leak. I'd be looking around the inlet side first...carby...manifold...then possibly vacuum.
  5. 'S right - check the simple and (perhaps) obvious, eliminate that before delving further. This approach works well with just about any mechanical dilemna.
  6. Thanks guys,

    Im actually away working for the next few days but will check for vacuum leaks when i get back home later this week
  7. When i said carbs serviced i meant a complete overhaul. Stripped and serviced with all new seals and rings.
  8. I would be checking your accelerator pump mech in the top of the carb they splutter like hell when they play up

    watch out for the plastic ramp slides they wear out you may need new ones also if you have got some water in they not enough to make it play up at idle and mid range but the accelerator jets are smaller than main jets and block up with less

    also check the diaphrams for pin holes and check for air leaks.

    good luck
  9. Also look at the Air box, i had a similar issue occuring with my Suzuki that when i hit the throttle it felt as if the bike was pulling back and would splutter but once past 4,500-5000RPM it would boot like hell.

    Turned out that my issue was the filter not positioned right in the airbox, One of the screws had come loose and was letting too much air in causing an issue at low revs, But the bike loved it higher up.
  10. And another vote for an air leak. I once owned an brand new 85', and airbox cracking was a problem on the early ones, (though I reckon if it was going to crack it would have done so many years ago). It's probably still worth checking around the lip where the intake hose join the airbox though.
  11. These carbies are sensative to a couple of things.

    Firstly the idle mixture setting effect the throttle when you crack it. It may be that when they ovhauled them they set the screw differently.

    Is it worse when cold or hot?

    The second thing they are sensative too is float height. chances are they set this differently after the overhaul.

    My guess is it isn't the air leak, but it wont hurt to look for it first anyway.
  12. cool, great to have help.
    im not currently running an airbox but i will check te rubber on the pod filters.
    thanks all for that, ill have a list of things to check now on friday.

    please any more.. feel free
  13. Was the carburettor rejetted for the Pod filters when you removed the Airbox??

    If not then take your plugs out and tell me if they have a white tinge to them.

    If they do then your bike is running lean and is the reason for your problems. Rejet now before your motor is stuffed.

    If they are Ochre colour then check for air/ vaccum leak on the carburettors..

    If they are black then you are running rich or have run rich, Bad petrol Etc. Give them a clean with the wire brush.

    They should be identical if your carburettors are all tuned properly.

    here is a good website for you to check out

    Have a look at the carburettor and spark plug sections for some idea of what i am talking about