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URGENT FZR 3LN1 engine rebuild

Discussion in 'Yamaha 250cc In-Line 4's' started by Forky, Jan 27, 2019.

  1. Forky

    Forky Active Member

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    Who here has had a successful engine rebuild on their little fizzer. And where did you get it done.

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  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    @Linkin and @Joker have both rebuilt fizzer engines that I know of for certain and I think that @risky may have had one rebuilt by the masterful @Murdo

    I think you'll find that because of the lack of available parts in the domestic market - no commercial workshop will touch them besides it being extremely cost prohibitive.

    There are workshop manuals available here with all necessary measurements and the FZR400 manual is in English for cross reference

    Give us some more info on what needs doing & why, we have sources for almost all parts, spread throughout many threads, OEM and others which are as good as OEM in all respects, and take it from there.
     
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  3. Forky

    Forky Active Member

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    I have 2 3ln1 motors that need looking at. One has cam timing out and 1 stripped bolt thread on the cam cap thing. And possible valve seats needs changing.

    And The other has excessive blowby, valve slap and needs rebuilding.

    I'm no expert as to what really needs done. I just need these two motors fixed/rebuilt asap. Not fussy on pricing either. But needs to be in qld if that's where they've been rebuilding them.

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  4. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Many owners source a 2nd hand engine rather than rebuild. This is your best option. Engine rebuilding never happens "asap". Just sourcing the parts is going to take a lot of time. As @ruckusman pointed out, it is prohibitively expensive and no one wants to do it. There is also the problem that most good mechanics get tired of working for nothing and being treated like ****, so they get a job in another field and just do bikes for themselves and friends. Those kind of people choose their customers, the customers do not choose them.
     
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  5. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    As above.. to take your engine to somebody to recondition it would be cost prohibitive.. to the point that you would be better to buy another bike with a good engine.. the other problem you have is all the potential other items you may find that need repair / replacement.. such as clutch, gears, selectors etc.. if your engines have been neglected to the point they are now it wont just be the engine that needs attention.
    What is the rush to get them done without being "fussy" on the price??
     
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  6. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    No such thing as a quick rebuild. That is, if you don't want to pull it apart again. Take it from someone that has bolted crankcases together without sealant.

    Step 1 - pull it apart
    Step 2 - identify what needs replacing/refurbishing
    Step 3 - find and list all the required parts, double & triple check before ordering
    Step 4 - put all back together. Slowly and by the book
     
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  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Good responses fellas

    From the symptoms you describe, unless the cylinders are out of tolerance, new rings would likely suffice, but before doing that I'd say across both engines valve clearances need to be done, then if you consider the bottom end to be good enough to be left alone, new rings and cylinders honed will likely get you there.

    That can be done with just the head and cylinders removed, save the cylinder base gasket and get a new head gasket.

    If the cam chain needs replacing, that can be achieved without complete bottom end disassembly - others have done it with the right link removing/installation and pin peening tool.

    A threaded cam cap retention bolt is very simple to remedy with a a coil insert and there is ample material to support it, any good machine shop will accomplish that - they don't take a lot of load and their tightening torque isn't high.

    The cylinder honing should be able to be accomplished at any capable machine shop, disassembly and reassembly by the book isn't difficult just for that part of the engine
     
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  8. Joker

    Joker See "about me" for contact details. Contributing Member

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    I've done 3 and a 400 engine. But I've had a shed full of parts for a few years now so i get by. They're not that hard to be honest, people are a bit scared of them but it's probably not warranted. Carbies on the other hand... ew.

    I've done OK with chinese rings from AHL (on ali express). Most of the bores I've come across are OK, it's the exhaust valve seats that seem to cop the brunt of the wear - and they seem a bit prone to bottom end issues. I'd take both motors apart and make a good one out of both, I've actually got one apart at the moment so could talk you through reassembly.

    Not around here much anymore though - easiest place to find me is club250 community on facebook. Good luck.
     
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