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Project First bike, the FZR250 3LN

Discussion in 'Your 250cc Projects' started by I_b_pirate, Feb 17, 2020.

  1. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Did you check the fuel level?
    Attempt to start it with the choke on?

    Get it to fire properly first because after you've done all of that work on cosmetics and electrics you won't likely want to deal with it not running, that would deplete your enthusiasm, it happens often with projects

    Carbs used to be buggers until we all worked out all of the issues, you'll get answers to every question and solutions to every problem here

    I recon with the km's you have on the clock, your needles and emulsion tubes will be fine

    Did you soak the carbs in petrol, there's a small cavity inside the float bowl chamber, sealed with a bung.
    This cavity feeds the idle circuit and if there's sludge or varnish in there it likely won't start or idle

    BTW it will be much more difficult to start without the airbox in place - lid off for a wee bit of petrol, then if it fires, pop the lid on
     
  2. I_b_pirate

    I_b_pirate Member

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    How do I soak the carbs? Do I just leave it submerged in fuel for like 6 hours? Total noob at this if you having guessed haha

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  3. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK to get anywhere with this, you need to let us know what suggested steps you've taken otherwise it will get repetitious and no-one will know where you're up to with the troubleshooting - it becomes pointless at a certain stage.

    To soak the carbs, remove the tops and diaphragm/slides, remember that the two inners slides and out slides have, or should have either different needles or needle heights.

    The rubber of the diaphragms and the plastic of the tops is petrol resistant, but it will pool in there if you just dump them in petrol.
    I'd also remove the float bowls FWIW.

    Get an appropriate container - a ~$5 container from Woolies or the like will suffice, fill with petrol, dunk in, leave it for an hour or so, lift out, turn and put back in facing another way.

    Then when you reinstall them, connect the fuel and fuel pump, power it and check the fuel levels as described earlier - fuel level is the most important factor to getting them running properly beside the worn emulsion tubes, but I don't think that yours will be substantially worn at this stage.

    Also given that it tried to fire when you shot some petrol down the carb throats, it will likely start with choke on, once they've been soaked which should work to clear any blocked jets, especially the idle jet circuit
     
  4. I_b_pirate

    I_b_pirate Member

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    I don't know if I measured the fuel levels right but I measured from the bottom of the bowl with them fitted and got varied results.
    1 and 4 both measured 10mm
    3 measured 21mm
    2 measured 16mm

    I did the same procedure for each carbs, opened the drain screw, got any bubbles out, turned on the pump, let it sit for a bit, checked the measurement, turned the pump on again and see if it moved and checked again.
    Fairly certain I did it wrong, but even to do it wrong and still get different results would still mean something is wrong.
    Havent soaked them yet, will do that at work tomorrow. Then I'll re test them and see it anything changes.

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  5. I_b_pirate

    I_b_pirate Member

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    Here's a pic of what I did, the marks were a rough measurement, I did get more accurate measurement using a steel rule though.



    [​IMG]

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  6. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK - you need to be looking in from the back at the casting mark on the bowls from this picture - in this shot - the fuel level would be at #7 - which is ~9.2mm above the casting mark on the float bowls

    [​IMG]

    From this post

    https://2fiftycc.com/index.php?threads/my-fizzer.872/page-32#post-15537

    The fuel level is 9.2mm above the casting mark line - to actually see it clearly the tank needs to be off as well as the airbox obviously, which is why I took the shot with them off of the bike entirely, so that I could show it

    It can be tricky propping the tank somewhere so there's fuel flow available, unscrewing the petrol tap from it's mount can give you a bit of movement to accomplish this

    Which reminds me, there is a good possibility that there's accumulated gunk on the fuel filter in the tank itself.

    Was there any surface rust in the tank, or old stale fuel?
    If you don't have a lot of fuel in the tank prop it forward or backwards towards upside down and remove the filters from underneath to check their condition.

    Don't worry you're getting there, but from what you've done it looks like they're not flooding, which is good and the difference might be down to bits if varnish or something else blocking some needle seats and making them close late
     
  7. I_b_pirate

    I_b_pirate Member

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    So the casting mark is 24mm above where I measured from meaning they are all below the mark. So hopefully with a good soak they should all come good and start getting some fuel.
    Cheers for the advice, actually learning a lot.

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  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Yes, I'd say there's blockages in your fuel supply back at the filters in the tank to start with, that's why you could get it to pop with a little juice down the carb throats, but of course it wouldn't run because it looks like there was at best insufficient fuel in the bowls.

    Soak them, sort the filters in the tank then give it another shot
     
  9. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  10. I_b_pirate

    I_b_pirate Member

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    Soaked the carbs and checked the filters in the tank, they look like they have been replaced so they all clear, I've replaced the inline filter and got the arrow pointing in the flow of the fuel. Measured the levels again and they are now all at the 9mm mark so that's good but still no fire.
    I've swapped the plugs on the coils and get small pops one way and the other way get pops out of the intake with the occasional backfire.
    Is it a matter of just keep trying and it will eventually fire?

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  11. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK, so just to recap and check - one coil wired to plugs "1 & 4", the other coil wired to plugs "2 & 3"

    The popping out of the intake to me says that coil plug switch is making it backwards, so switch it back to how it was

    a small amount of petrol down the carb throats get you any joy

    AAH and with the choke on?
     
  13. I_b_pirate

    I_b_pirate Member

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    Havent put fuel down the carbs as I've left the fuel at work so gonna also pick up some start ya bastard. Gonna try my hand at trimming the leads tonight but it smells like it's getting fuel now, before I couldn't smell anything. I'm sure I'm getting closer.
    My choke lever is broken so had to lever it out with a screw driver but still nothing.

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  14. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Yes, it sounds like the inline fuel filter was blocked, start ya bastard is a good next step
     
  15. I_b_pirate

    I_b_pirate Member

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    Yeah she was black on the inside. The new one I got is just a temp till I get the proper one.[​IMG][​IMG]

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  16. I_b_pirate

    I_b_pirate Member

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    How the hell do you get the clips back on after you trim the leads, just broke the 1&4 clip for the leads after struggling with it for 20 min. Is there like a sneaky way of going about it?

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  17. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    You have to spread the copper wires inside apart so the screw can grab the soft section of the lead.
     
  18. I_b_pirate

    I_b_pirate Member

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    No screw, there's a spike inside that goes into the wire to connect with the copper, then this clip to keep them in place. As you can see I destroyed this one.[​IMG]

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  19. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Been years since I dealt with those wires at the coils, from memory however I think I applied a little grease to make refitting the clips simpler - OH and I swore heaps
     
  20. I_b_pirate

    I_b_pirate Member

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    Yup definitely did the swearing part especially when the screwdriver went into my hand. Maybe I can fashion a better fastener for them somehow

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