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Help FZR250 - coolant leak in hardline behind block/head

Discussion in 'Yamaha 250cc In-Line 4's' started by skylinerd1, May 4, 2019.

  1. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    The carbs measure 26mm on the outlet to the engine.

    The jet needle is a 5CL2. So possibly the complete engine is a zeal unit? No way of easily telling that? I did see a 1HX in the casting but from skimreading through here it doesnt tell you much.
     
  2. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    The carby's look like they're FZX250 Zeal then with that jetting and needles
    Needle's should have the clip in the centre (3rd from top) slot like Blair mentioned above

    If you want to get the full potential out of the bike then i'd look for a set of 3LN3 / 3LN5 carb's, rebuild them and try them out

    I read somewhere the Zeal has a different number on the casting here on the head, but i cant remember whether it's a 02 or a Y3
    This is on my spare 3LN3 engine

    20190507_163402.jpg
     
    Last edited: May 7, 2019
  3. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    If it has an engine number on the crankcases underneath the carbs, read that somewhere, then it is possible to know if it is a 3LN series.
     
  4. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    Jeez this bike.... Is beginning to try my patience! Appreciate the help though guys! Did someone mention you can identify zeal motors from fzr's by the cam cover? Or are they all the same to?

    There are no numbers on the front left side (looking from front of bike) as per the ones shown in the bike identification thread.

    IMG_20190507_193325[1].jpg IMG_20190507_193415[1].jpg
     
    Last edited: May 7, 2019
  5. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Zeal motors have metal water pipes and some small differences, doesn't mean it can't be a zeal motor.

    Facing the front of the bike, check the lower left front of the crank case for number stampings. The other location is on top of the casing and behind the clutch cover, but I have seen this just stamped 1HX or blank - possibly indicating engine case replacement in the past.

    I wouldn't worry about what the motor is, exactly - 3LN3-3LN5 are all the same. Only the 3LN1 and late 3LN6/7 differ because of - internal filter (3LN1) and reduced redline (16,500 from 18,500 - Zeal is about 15,000) / different camshafts (3LN6/7). Speculated to use Zeal cam profiles.

    I would however get the jetting and needles setup as they should be for that variation of carb. Not much you can do about the inner diameter being 26mm instead of 28mm unless you have a precision boring machine and 28mm throttle butterflies to match.
     
  6. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    Lower left crankcase has nothing on it. The only numbers I could see are in the photo in post #44

    I will quickly have a look around to see what I can find as far as carbs go. Iv found one carb someone is calling a parts carb at $80 as he reckons it to dirty to fix... so probably give that one a miss and I know a motorcyle shop about an hr away has three of these bikes as parts machines who I was going to get the cables I need off but he's been busy so will try him again tomorrow.

    Zeals should have spin on oil filters unless the crank case has been swapped? This one is a catridge filter underneath.
     
  7. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Correct. That makes it a 3LN1 motor assuming the sump / head etc haven't been changed out.

    As you have what appear to be zeal carbies, I would be going for 3LN3-3LN5 jetting and working out any issues because of the smaller dia. throttlebodies from there. Some relevant questions though - what does the tacho red zone start at, and what is the part number on the TCI / ignitor unit + what colour is the sticker on it?

    Going back to your question about ticking noises - yes, valves can tick. It is known as a 'Yamaha thing'

    As long as the clearances are all within spec and there are no wild variations, don't worry about them ticking.

    However, you can definitely hear the timing chains when they are stretched - mainly on deceleration with no load (ie, holding the revs and then dropping the throttle to idle, you will hear it ticking/grinding as the motor revs down)
     
  8. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    The previous owner said the thing revved out no problem. He said he reckoned it needed about $900 worth of work to get it back on the road properly and thats certainly beginning to sound about right. Got indicators, carb to engine boots and a new fairing kit on order from china... a punctured rear tyre, as well as all this stuff iv posted in here to contend with.

    IMG_20190507_213732[1].jpg IMG_20190507_213953[1].jpg IMG_20190507_213858[1].jpg IMG_20190507_213918[1].jpg
     
    Last edited: May 7, 2019
  9. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Igniter part number links to 3LN1 model code. Along with the tacho being 18,500rpm where the red zone starts.

    From my view, you definitely have a 3LN1 bike, with later model carbies.

    These links will take you to your exact bike, just unsure on which colour code is yours, there are two variants for white 3LN1's

    https://www.megazip.net/zapchasti-dlya-motocyklov/yamaha/fzr250-8618/fzr250-19068/3ln1-768319

    https://www.megazip.net/zapchasti-dlya-motocyklov/yamaha/fzr250-8618/fzr250-19068/3ln1-768321
     
  10. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I wonder if those metal ring's you have holding your airbox boot's open are causing an issue ?
    They look like they're 1.6mm to 2mm thick ?
    It may be causing the airflow into the carb's to bypass or slightly bypass the 2x port's that feed the main jet and pilot jet circuit's ?

    [​IMG]



    Also when you get it running next check your fuel level's, they should be 10.5mm above the line on the float bowl's
    You just need to turn the ignition key on and off a few time's to prime the carby's, when the fuel pump switches off when you turn the key on the carby's are full.
    You get a piece of clear pvc tubing and fit it to the drain barb on the lower part of the fuel bowl and hold the other end of the fuel hose up above the top of the carby, then open the drain screw
    Fuel will flow out the drain into the hose and then you can measure the fuel height against the line on the bowl

    The float's inside the fuel bowl should be sitting 14.7mm off the base of the carby with the needle (needle and seat needle) just touching the tab on the float



    3LNcarb06mplopendjpg427c9feb4be4a5a4ea047ceace3cc418.jpg



    FloatLevel_Yamaha_FZR250.jpg
     
    Last edited: May 7, 2019
  11. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    1.6mm thick rings. If I have to I will put them in the lathe and machine thinner. As when they were shrunk the boots would of been that size anyway. I find it hard to believe they would make a huge difference. Im prepared to tune around them if it end up being an issue as I dont want to see shrunk boots in there again.
     
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  12. Murdo

    Murdo The Good Doctor Staff Member Premium Member Ride and Events Crew Contributing Member

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    The rings look to be only about 10mm long so don't think they would interfere with the air bleeds.
     
  13. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    Not even that probably only 5-6mm long.
     
  14. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I would have thought that a 6.5% reduction in air velocity could cause an issue with the 1.6mm thick ring's inside the boot's?
    They could disrupt the air flow across the 2 port's ?
    It would give the carby's the same sort of signal as a blocked/partly blocked air filter, making them run a touch richer, which may account for the needle clip being on the second notch down instead of the third notch.

    Another thing is the Zeal's run 2x longer air box boot's on the 2x inner carby's which may make the 2x inner cylinder's run a touch leaner, they would help with the bottom end pickup
    Might have been a way of compensating for the 4x main jet's being the same size instead on using richer one's on the outside 2x carbs

    The FZX250 Zeal's run the longer 2KR type intake manifold too so that's another thing to factor in, as well as not using the EXUP in the exhaust system


    Brand new air box boot are still available from Yamaha, they cost around $15ea
    Part number 1HX-14453-00-00, Joint Air Cleaner x 4


    587445.png
     
  15. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    Nah its nothing to do with how the clip is set. I did that box mod like three days ago the bike was running with big gaps in the boots and the airbox was full of crap which is why I did it. Half these bikes must of been running around with those boots shrunk down like that so I find it extremely hard to believe this is going to effect the running in any major way. These carbs were dirty and the wrong ones THAT IS THE ISSUE 100%! I have no idea why that clip is set to 2 perhaps whoever fitted this carb set decided it might run best set that way I have no idea.

    All I can do is try it. My main concern right now is obtaining the correct carb set, exup cables, and a throttle return cable everything else is a secondary concern atm.

    Does anyone have a set of known decent carbs around or seen an for sale? I have tracked down one at a motorcyle wrecker here in NZ for $140 (sounds reasonable) which he claims was running when he obtained the bike just waiting on him to get back to me and confirm it is indeed one of the correct carb sets.
     
  16. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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  17. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    Yep I just contacted that guy just before you posted that up. Its an old post though.
     
  18. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yeah 19th Feb :thumb_ups:
     
  19. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    Not on the winning page yet....

    Heres where im upto now after receiving a replacement carb set its in a sorry state but not end of the world I think.

    I have two 5CT7 needles and two 5CT9 needles each pair were side by side in each paired outer carb set! all on second clip again.... And thats not where the malarky ends! Needles are worn.

    I have one snapped diaghram spring. One needle jet housing where the n8 638 holder just spins with the nut... How is the best way to attack removing this?

    jetting is 100 & 42.5 on outer carbs and 97.5 & 42.5 on the inners.

    So almost certainly a 3ln3/5 carb set.

    IMG_20190515_184226[1].jpg
     
  20. skylinerd1

    skylinerd1 Member Premium Member Contributing Member

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    My other question is can i substitute the zeal springs with their helper springs and will that work to keep the needles from wearing? or is something different with the diaphragm slide and needles that wont allow this?

    Also best place to order just the needles and emulsion tubes or not possible?
     

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