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Bandit 250, will not run.

Discussion in 'Technical and Troubleshooting Torque' started by ron81, Apr 15, 2008.

  1. I have a GSF250 (1991 Grey Import) that will not start. I have had two buke shops work on the bike and they get it started, But they have not been able to fix two probs. One is that it has nothing under 4 grad. You have to ride the cluch untill you have a bit of speed going. After that she is fine and will rev out to red line. The secong prob and where I am now is, if you let it sit around for a couple of days I can not get it going again. I have changed the plugs twice, replaced the air filter and oil, changed the fuel.

    Does anybody have any ideas, I simply am stuffed as to what is wrong.

  2. At a guess sounds like it might be a problem with the carbs - specifically the pilot jets which regulate the engine at idle and low engine speeds. Possible they may have clogged up with crap from some bad fuel and be in need of a decent clean.
  3. Float needle not quite sealing.

    It's flooding down low and once the needle lifts it's fine.

    Clean the bottom end of the carbies, set your float heights and synchronise.

    To get it started:

    No choke.
    crank it over and wind the throttle slowly open.
  4. I have dismantled the carb and cleaned as much as I could and did not see anything out the norm. I will check the needle sealing and give it another clean.

    How do I set the float heights?
  5. complete newbie with bikes but hows the battery, i mean its odd that up higher in the rev range its running fine but down low its got nothing, perhaps the alternator is kicking in above 4k?
  6. Ummm...not that one. ;-)

    Trevor G
  7. Nope. Different engine, different carbs (bigger and more of them).
  8. Band new battery, fully charged. Just a note motorbikes do not have an alternator, they have a flywheel magneto, hence they can normally run without a battery. They just need a battery if you have electric start and other modern fancy stuff.

    jd, I am have trouble downloading the files fom your suggested link. I get sent to a Megaupload site. What am I doing wrong??
  9. Part way there. When you click on one of the links it should go to the Megaupload site - but there should be a random 3-letter code displayed to the right of the logo. Type that code in the white box to the right of it then click the download button to the right of that.

    It was the only easy way I could find of making the files available I'm afraid.
  10. :oops:

    good for a laugh at least
  11. :LOL:
  12. My comment re alternators was based on the fact of all the bikes in my garage, only one has an alternator, hence my broad statement. :grin:
  13. I'd say you own a few trail bikes then. Road bike's haven't had magneto's since the 60's (with a few exceptions)

    The Bandit has an alternator.
  14. You wouldn't be able to get a smooth enough initial voltage curve with just a magneto, let alone enough current being produced. (The dirtbike magneto/small motor magneto uses a coil at the magnet "spot" to produce a "spike" of voltage. It's extremely reliable, but however needs mechanical linkages to advance the timing (as opposed to solid state timing advancement on modern engines), and cannot support constant-voltage accessories, hence the need for a magneto
  15. JD, Thanks, I downloaded the files, printed out and have had a good read. Could not find this info on the net, so thanks again,

    Hey guys sorry I made such a broard statement. What I meant was I did not think the 250 Bandit had an alternator as obvious as the one mounted on my 1200 Bandit. Plus just showing my age and refering to it what my old man would always call it. Yes I do have trail bikes and a couple of not so young bikes. Sorry we got away from my prob at hand.

    Mind you I have been down the electrical path. Changed the coils and the black box.

    I will have another go at stipping down the carb and such. I was hoping someone might enlighten me to some stupid thing I may have overlooked.

    Just a foot note I can get it start with a squert of fuel down the carbs but it only runs for a few seconds and dies.

    Now you guys can see why this is driving me crazy.

    Thanks again guys. :grin:
  16. At least you have demonstrated that the problem lies in the low speed circuit in the carbs. The mixture would appear to be very lean, as in blocked pilot jets (all of them?) perhaps due to dirty fuel.

    Or you might have insufficient fuel in the carbs - the float levels (if someone has been "adjusting") could be too low.

    Have you checked the pilot mixture adjustment screws? They should be somewhere around 1 1/2 to 2 turns out as a rough starting guide, I think.

    One thing I am not sure of - when did the problem occur?

    What happened just before the bike started playing up?

    What does the choke do on these models - is it a fuel enrichening device, with cable or lever operated plungers on the side of the carb? If so, then something is preventing fuel reaching them (too low a fuel level?).

    Have you checked the drain screws to see that you actually have fuel in the bowls?

    If you have a diaphragm tap it has possibly failed and needs to be on the Pri position. Remove a fuel hose from a carb and make sure fuel flows out of it. If not, there is your answer.


    Trevor G
  17. Once I get the chance I will check all the suggested check items.

    Full story, I purchaced the bike from a mate with the full knowledge he was having trouble starting it. It had been stitting around for about 6 months. I drained the carbs and tank. Changed the oil. Install new plugs and new filter. I get the bike started and off we go. But from the word go it had nothing under 4 grand, above that fine. If I let it sit for a couple of days had a buggger of a time to get it going again. The last time I got it going, went for a ride and it just died completely, no response at all. Replaced plugs agian. Reset the needle jet ( I thought it was running to rich). I have even changed the carb (but stupidly did not do all the suggested checks). Now she does not want to go at all.The tank is off and I have plugged the vaccum line. I fill the bowls through the feed line manually. The petrol tap is dodgy and I will need to replace it. Does not shut off when there is no vaccum. The choke is a plunger/slide type. I think the lack of fuel seem to be the prob, because it seems like it does not want to fire at start unless I give it a squert down the carbs.