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Project ‘89 FZR250r 3ln1

Discussion in 'Your 250cc Projects' started by Brandon Otte, Jan 8, 2021.

  1. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Replace the plugs, leads and caps. Water conducts electricity so if the insulation is breaking down you'll get a short and no spark/fire.
     
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  2. Brandon Otte

    Brandon Otte Well-Known Member

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    Quick update - I bought new plugs, removed fairings and with a positive attitude started removing the plug leads... and found the cylinder which was giving issues had a loose spark plug. I did change plugs and ended up putting the original plug back in after cleaning it, at the time I was struggling to get the socket in there which was a lot easier today. So tried tightening it and it only goes so far and then just spins without ‘nipping up’. So I’m afraid the spark plug threads in the head are shot/crossed. It has sealed for now and is running as it should but I fear this is a time bomb. That noise I thought was the spark shorting was actually the compression passing by the loose plug. Can I re-tap the thread in the head with any luck and without putting metal bits in my cylinder? Are there any options viable without removing the head and putting a helicoil in.
    I did consider thread taping the spark plug itself but not how it’ll go under heat.
     
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  3. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Probably best to have that sort of repair done with the head off... either Heli-coil or Time-sert will do the job.
    Time-Serts are similar to Heli-coils but are solid and you can use Locktite on them..
    Make sure that you use anti-seize on all your plugs and dont over-tighten them...
     
  4. Murdo

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

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    Sounds like you plug spanner is too big on the outside and is not allowing the plug to seat properly. Threads can be cleaned up using the right tap, use plenty of grease on the tap to collect any bits of old thread.
     
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  5. Brandon Otte

    Brandon Otte Well-Known Member

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    yeah thanks for that, I had watched a quick video explaining the same thing - was going to retap the threads but I think what’s actually happened is my spark plug socket is, like you say, too big and isn’t catching the spark plug once it’s part way in. So luckily no damage done!
     
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  6. Brandon Otte

    Brandon Otte Well-Known Member

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    In other news:
    I’ve removed the carbs on the 3ln1 and just opened the #1 carb(left hand if sitting on bike) and had had a quick play. Removed the two jets and sprayed carb clean in there, it’s all clean inside from what I can see but I’ll definitely read the rebuild posts and follow them religiously. B0B58587-63D3-4F11-A450-F5AB7EF1CF76.jpeg FEB5B728-0D1D-4F8C-9651-6EB9FC0EF391.jpeg 345A4511-0CF8-439F-81E5-F4818C6F1478.jpeg
     
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  7. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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  8. Brandon Otte

    Brandon Otte Well-Known Member

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    Thanks was just going through the litetek guide - its overwhelming. I was at the local bike shop last week and got a number from the mechanics there for an elderly gentleman who is quote “a carburettor guru”. He’s only got a landline number which is reassuring for some reason. I may give him a call and see if will rebuild my carbs. Atm it’s just a bit too much time to commit with a young family.
     
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  9. Murdo

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

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    And don't forget to get that merge chamber bung out and clean the tiny holes.
    Some new screws in the float bowls would be a wise investment.
     
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  10. Brandon Otte

    Brandon Otte Well-Known Member

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    @Murdo which one is the merge chamber bung?
     
  11. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  12. Brandon Otte

    Brandon Otte Well-Known Member

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    Ahh wow, these carbs are a puzzle. Can one take the floats off without needing to reset/adjust/height them?
     
  13. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Yes just grab the base of the float and twist/pull. But it's worth checking/setting the float height to get the correct fuel level.
     
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  14. Brandon Otte

    Brandon Otte Well-Known Member

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    Quick update - I’ve dropped my carbs off to the ‘carb guru’. He’s a wonderful elderly gentleman, very knowledgeable and fills his spare time with bike carb repairs. Very reassuring knowing someone who has all the knowledge, tools and contacts is working on my carbs. Sorry to everyone on here who offered their help as I just can’t commit to rebuilding them myself this time round. Will update once I have them back(no rush basis).
     
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  15. Brandon Otte

    Brandon Otte Well-Known Member

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    Another update - so I’m still waiting for my carbs to be rebuilt. It’s been so long since I last rode my bike. I’ve sold my 88 2kr which was snapped in no time at all, sad to see her go but this 89 3ln is in pristine condition and I can’t have two bikes as much as I’d like to.
    The gentleman rebuilding my carbs has stripped and ultrasonically cleaned them. Last I spoke to him he explained the seals were in poor condition as well as old fuel gummed up. Unfortunately he’s still waiting for the seal kit from overseas which is proving to be a real problem due COVID.
     
  16. Brandon Otte

    Brandon Otte Well-Known Member

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    Great news everyone - I am picking up my freshly rebuilt carbs tomorrow morning! Will upload some photos and videos once she’s up and running
     
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  17. Rahyvin

    Rahyvin Active Member

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    hi, did you manage to get the bike running?
     
  18. Brandon Otte

    Brandon Otte Well-Known Member

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    Hi, yes I sure did!

    So just quickly - I picked up the carbs, put them on the bike and found fuel to leak from the carb inlets… so took them back for those seals to be replaced(not sure why they weren’t all done the first time).

    Anyway bike is all back together and running well. Except at WOT.
    So runs and Revs really well at all other throttle positions, but, full throttle she misfires and doesn’t rev as she should. I’ll replace the plugs first before blaming the carb tune, potentially check the leads too.

    The guy rebuilt them is very experienced with carbs and motorbikes with over 50 years experience. He hasn’t balanced the carbs with a vacuum tester, instead he’s done them by sight - looking through the throttles held up to light which he assured me he’s always done. He also set the main jet needles in half way I believe if I’m not mistaken.

    Does anyway have any opinions on why I have this full throttle issue? There’s a bit of black smoke out the exhaust when I rev it wide open, I can imagine it’s either poor spark or a too rich mix.
     
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    Last edited: Jun 15, 2021
  19. Brandon Otte

    Brandon Otte Well-Known Member

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    It’s been a while since she was all in one piece.

    3A817421-E555-4DDA-A784-F6308682B418.jpeg
     
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  20. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    ... and found fuel to leak from the carb inlets
    What do you mean by carb "inlets"? Fuel Tee seals?

    So runs and Revs really well at all other throttle positions, but, full throttle she misfires and doesn’t rev as she should. I’ll replace the plugs first before blaming the carb tune, potentially check the leads too.
    Okay change them and get back to us.

    The guy rebuilt them is very experienced with carbs and motorbikes with over 50 years experience. He hasn’t balanced the carbs with a vacuum tester, instead he’s done them by sight - looking through the throttles held up to light which he assured me he’s always done. He also set the main jet needles in half way I believe if I’m not mistaken.
    That doesn't mean anything, he might be a genius or an idiot.
    The carbs were rebuilt using what parts and what brand of kit exactly, Keyster, Chinese?

    Does anyway have any opinions on why I have this full throttle issue? There’s a bit of black smoke out the exhaust when I rev it wide open, I can imagine it’s either poor spark or a too rich mix.
    Sounds like a reasonable assumption, but until you try your new plugs and tell us what parts were fitted to these carburettors it would be wild guesses on our part.
    Cheers
    Blair
     
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