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First Bike - Troubles getting it to leave home...

Discussion in 'Yamaha 250cc In-Line 4's' started by Shitfight, Jul 1, 2016.

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  1. Shitfight

    Shitfight Member

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    Hi all!
    So I got myself a cheap ($400) first bike - FZR250 2KR :dance2: which is in fairly rough shape cosmetically.....probably not a bad thing considering I just got my l's.

    Anyway, mechanically the bike seems fine, I pulled the carbs off and opened the bowls, which seemed spotless. I gave them a shot of cleaner anyway. I found the reason it wouldn't run to be a blockage on the fuel inlet for the carbs, so I cleared that out and it started right up!

    After sorting out some wiring issues, I fired the bike up and tried to ride it up our steep driveway...and it stalled :lolsign: When I tried to fire it back up it would only idle at full throttle and stall at anything less.

    Next day I got it up and onto the road and had a few runs up and down the street, until it stalled again and would only idle at full throttle again.

    I noticed that when it runs good the carbs seem fine and clear, but when it's not running right it seems to spray a mist of fuel back out of the carbs...?

    So yeah that is where I'm at, and I have no idea what to do....It seems it wants to run great in the yard but doesn't want to leave! :headbang:
     
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    Shitfight, Jul 1, 2016
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  2. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    OK what you need to do is a check of the whole fuel system. Start from the tank. Have a look inside and see the condition. If its rusty you'll want to flush out as a temp fix, as well as replace or add an inline fuel filter if there is not one. Try running the bike with the fuel cap open, a blocked tank breather can stop fuel flow.

    It sounds like the carbs have a blockage somewhere. You will want a set of JIS screwdrivers for the bike, there are no phillips screws on a jap bike unless someone has the replaced the whole lot of them (common thing is to replace them with allen head bolts).

    Go to your local repco or bursons and find "Threebond Engine Conditioner" in the green/silver can. You will want to take all the jets out for each carby and soak them for a few hours or overnight. While you have the carbies apart, its a good idea to check all the diaphragms, needles and tubes, and o-rings. @maelstrom does carby kits for the FZR250's. You will want to inspect the float needles to make sure they're not damaged. Make sure your carb boots are done up tight.

    If you're getting a fuel leak you need to examine all the hoses and make sure none are split or brittle. FZR's use 6mm or 8mm ID fuel hose, you can get it by the metre from supercheap or autobarn and the like.
     
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    Linkin, Jul 1, 2016
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  3. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Welcome to the forum's,
    i have only recently joined in the last couple of week's and also have a FZR250, mine is a '90 model though.

    Spitting back out the carb's can also be valve clearance's, but in your case i think it most likely carb's
    What was blocking the fuel inlet? it may still have some of the same in the line, might be worth swapping in a new fuel hose and filter while you at it.
    When tuning the bike you need the air filter and air box lid fitted and tight and make sure the carby boot's to air filter box are all good (haven't shrunk)
    While the carby's are off check out the condition of the rubber manifold's where the carby's slide into, if they are cracked they will be a vacuum leak and you'll struggle to get thing's right.
    Start the bike and let it idle, now spray some carby cleaner, degreaser or wd40 onto the carby boot's and listen for any idle speed change's, it there's a leak it'll run funny or different to what it normally idle's like
    Does it smell rich at the exhaust when it's idling ?
    You can sort of tune the carby's to compensate as a bandaid fix but it won't be perfect till you get them sealed off properly and adjust it all again

    Post up some pic's of your bike too when you get a chance

    Cheer's, Craig
     
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    my67xr, Jul 1, 2016
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  4. Shitfight

    Shitfight Member

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    Thanks for the quick replies guys, in the morning I'll check for these things,I have risen the bike with and without air box when I have it working and it is much better with it, feels powerful right through the rev range, without there are dead spots...

    It seems strange that it has this problem then when it sits overnight and on charge it will run fine again.Could a bad stator or regulator cause this?

    I have already run carb cleaner through fuel houses when I found the blockage...

    The fuel tank had surface rust so I filled it with gravel :idk: and shook it then flushed with diesel and then petrol as a temp fix so it should be ok for now.

    Did do a quick check and must valves seem to be within range, except for 3rd intake valve (2nd cylinder) which looks to be 0.02'm below min spec.

    These don't have a variable valve timing do they?

    Thanks
    Alex
     
    Shitfight, Jul 1, 2016
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  5. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    These bikes have fixed valve timing, but the CDI/ECU adjusts the advance of the spark as the RPM increases. Valve timing will drift when the cam chain is stretched. If the bike is running better without the airbox, you might need a new air filter.

    Valve clearance is 0.11mm-0.20mm intake and 0.21mm-0.30mm exhaust. You change the shims to get the clearance on the loose side of the spec, so at the next interval you won't need to adjust again, just check that the clearance is within spec.
     
    Linkin, Jul 1, 2016
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  6. Shitfight

    Shitfight Member

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    Sorry I made that a bit confusing, does run better with the air box, but when it's running bad there is no difference with or without.

    I didn't have much time when I was doing it but I checked the clearances quickly with a 0.1 0.15 and 0.2 for intake side the 0.2 didn't fit in any and the 0.15 was snug fit for most except that one valve.

    Will have a play around with it in the morning.

    Thanks
    Alex
     
    Shitfight, Jul 1, 2016
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  7. Shitfight

    Shitfight Member

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    Another note, the pilot screws (they are the ones below the slide diaphragms right?) Are only about 1.5 to 2 turns out
     
    Shitfight, Jul 1, 2016
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  8. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Standard settings are 2.5-3 turns out as they came from the factory. The mixture screws are the ones on the float bowl side.
     
    Linkin, Jul 1, 2016
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  9. Shitfight

    Shitfight Member

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    I didn't see any on that side....I did pull these out and clean them they are small needle screws with a small passage that leads to just below the throttle blades...I will get a tomorrow
     
    Shitfight, Jul 1, 2016
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  10. Shitfight

    Shitfight Member

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    When I screwed them further out it bogged down more before revving
     
    Shitfight, Jul 1, 2016
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  11. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Have you got a photo of your carbs? As these bikes are all imports, parts get mixed n matched, so it helps to identify what is actually on the bike. You could even have 3LN carbs on there with worn out needles and tubes.
     
    Linkin, Jul 1, 2016
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  12. Shitfight

    Shitfight Member

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    Should be able to get a photo tonight, I thought the 3ln carbs didn't fit the 2kr?
    Should there be o rings on the pilot screws?
     
    Shitfight, Jul 1, 2016
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  13. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Yes there should. Have a look here if you're unsure of what goes where on the carbs. 2KR and Zeal are supposed to have 26mm carbs, but not sure if that's just an inner diameter change - it would make sense as you don't have to make multiple sets of carby boots, just bore out less of the carb body.

    http://litetek.co/Guide_MikuniBDST_Rebuild.html
     
    Linkin, Jul 1, 2016
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  14. Shitfight

    Shitfight Member

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    Thanks for the link, nice to see instructions in such high detail. So by the looks of it my pilot screws are definitely on the front or diaphragm side, and didn't come out with any o rings so probably getting way to much fuel I'd assume. Looks like I'm in for spending some $$$ and time rebuilding the carbs....just got done with my brothers Suzuki Sierra :headbang:
     
    Shitfight, Jul 1, 2016
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  15. Th3_Huntsman

    Th3_Huntsman Senior Member Contributing Member

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    The o rings can get stuck in the carbs body. Check with a pen torch.
     
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    Th3_Huntsman, Jul 1, 2016
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  16. Shitfight

    Shitfight Member

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    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    The last photo is pointing at the pilot screws...

    Does this look right? If it does I will order the 2kr kit.
    I'm also going to replace the voltage regulator because it's cheap and I'm skeptical about the one I've got..

    Hopefully this is all it needs! :bowdown:
    Thanks
    Alex

    untitled 1.png Untitled 2.png untitled 3.png untitled 4.png untitled 5.jpg
     
    Shitfight, Jul 2, 2016
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  17. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Those are definitely 2KR carbs :thumb_ups:
     
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    Linkin, Jul 2, 2016
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  18. Shitfight

    Shitfight Member

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    Thanks for all the help, I've ordered the parts - if it doesn't take long enough already, Paypal is only allowing me cheques for some reason :mad:

    When they arrive I'll rebuild and take some photos and hope it all works out! After the learner course, I've been dying to get out on the road!
     
    Shitfight, Jul 2, 2016
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  19. Shitfight

    Shitfight Member

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    One last thing... Does anyone know where I can get one of those brass cap screws for the emulsion tubes?
     
    Shitfight, Jul 2, 2016
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  20. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Did you break them? You could try mikunioz
     
    Linkin, Jul 2, 2016
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