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Help Bandit 250 (GJ74A) ignition timing

Discussion in 'Your 250cc Projects' started by whyshouldIregister, Mar 21, 2025.

  1. whyshouldIregister

    whyshouldIregister Member Premium Member

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    Ignition timing on the bandit is way too advanced and there doesn't seem to be an apparent way to adjust it as all the components in the ignition timing system are screwed in

    Any help would be appreciated [​IMG]

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    whyshouldIregister, Mar 21, 2025
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  2. Murdo

    Murdo The Good Doctor Premium Member Contributing Member

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    How do you know it is too far advanced?
     
    Murdo, Mar 21, 2025
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  3. gyro gearloose

    gyro gearloose Well-Known Member

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    as above... how do you know its advanced? have you even got it running yet? in which case...:idk:

    looks like a regular, if rather dirty, trigger assembly. firing mark when fully advanced and TDC mark...
     
    gyro gearloose, Mar 26, 2025
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  4. whyshouldIregister

    whyshouldIregister Member Premium Member

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    Fuel is spitting out of the carbs on ignition stroke which would mean that the intake valves are still open when spark is firing?

    That's just my guess I'm not a certified technician

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    whyshouldIregister, Apr 3, 2025
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  5. Linkin

    Linkin The Mechanic - Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Would be more worried that your carbs are flooding before ignition timing being wrong. With these bikes it's fixed timing plate and ignition curve programmed into the ignitor unit.

    More likely to have spark plug leads going to the wrong cylinders, or carb trouble
     
    Linkin, Apr 3, 2025
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  6. gyro gearloose

    gyro gearloose Well-Known Member

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    ignition stroke? what?


    just take it for granted, ignition is fine, if maybe the wrong firing order... which is a simple fix, make sure leads go to appropriate coil and coils go to appropriate plugs in wiring harness... one in a million chance its module related...
    but it wont cause what you see...

    its normal to see a bit of fuel mist from a carb when running, especially at low rpm. "reversion", all to do with sound waves and lengths and valve timing, but i get the impression you mean raw fuel spraying in large quantities... or enough to be noticeable...

    that suggests the valve clearances, or the cam timing is waaaaay off... and if youve turned it over with cams timed wrong it wouldnt turn over the second time, lol. unless its been forced and bent a valve(s).

    along with possible carb issue. float levels...

    two things you should have already checked... carbs. clearances.


    whatever. is it even running yet? carbs off, bit of fuel down the intakes, and cranked it? it fires, it revs, it dies. you know its running, move on... last thread ended on the starter button but no mention of it making desired popping noises... if it doesnt run, you check other things like carbs, compression (does it crank smoothly, evenly, or not? ) or state of valves by popping carbs and exhausts and looking...
     
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    gyro gearloose, Apr 3, 2025
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  7. whyshouldIregister

    whyshouldIregister Member Premium Member

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    Starter button issue was a whole rabbit hole of **** wiring and shorts but I got it fixed in the end, and sorry for my **** terminology I'm still learning all this.

    Firing order is correct and it wants to start, after taking off carbs and cleaning I noticed the intake valves were corroded, decided to test and yeah it's a pretty bad leak coming from the intake valves.

    I guess that's the main issue as to not starting and explains why it was spitting fuel back so much

    This is my first project so I'm gonna make a few errors but we start somewhere

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    whyshouldIregister, Apr 7, 2025
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  8. whyshouldIregister

    whyshouldIregister Member Premium Member

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    And when I say spitting fuel I mean spitting an abnormal amount of fuel, thanks a lot for the advice though

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    whyshouldIregister, Apr 7, 2025
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  9. whyshouldIregister

    whyshouldIregister Member Premium Member

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    Final note, getting my hands on an endoscope soon enough so I'll be able to check cylinder condition, hopefully none of the valves were open this whole time

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    whyshouldIregister, Apr 7, 2025
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