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Help Copper pieces in oil

Discussion in 'Yamaha 250cc In-Line 4's' started by Xavier492, Jul 12, 2018.

  1. Xavier492

    Xavier492 Member Premium Member Contributing Member

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    Hi everyone, I have a 1990 Yamaha FZR250R 3LN3 and it has been very reliable up until about a month ago.
    Two months ago I took it to a dealer to have the cam-chain and drive-chain replaced with a few other little other bits and the mechanic (who owned many FZR's) said the engine looks to be in good condition aside from a minor oil leak.

    So I took apart the sump and used a gasket from aliexpress along with some new oil and oil filter.
    I let the bike warm up - it sounded good, but then 2Km up the road it started making a rattly noise that got worse as I revved.
    I deduced that aliexpress and ebay don't sell the correct sump gasket as they don't seal the oil filter feeds - why my bike died.

    I stripped the bike and have checked the piston rings and con-rod bearings and they all seem fine. Also, the bearings look chrome, not copper.

    I was then told that it is the clutch basket, but the basket itself looks fine (I will inspect the 6 clutches tonight).

    Anyone know what the copper pieces are from?
    Sump1.JPG Sump2.JPG Sump3.JPG Sump4.JPG Sump5.JPG Sump6.JPG
     
  2. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Copper usually indicates wear of the main and conrod bearings.
     
  3. Xavier492

    Xavier492 Member Premium Member Contributing Member

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    I see, but all the bearings look chrome and had no play, and looked better than the one you tore apart (the virgin 250). So far I have only found copper shavings in the sump and nowhere else. I did find very minute silver particles on the clutch basket.
     
  4. Andych

    Andych Well-Known Member Premium Member Contributing Member

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    Plain bearings such as found in Conrod little ends will be a tin / lead / zinc material depending on age etc. Big ends on the FZR250 will be steel backed White metal which again is a tin / lead / zinc alloy.... they certainly wont be "chrome" but they may look polished due to wear. Not having pulled an FZR250 apart I dont know where copper would come from unless it is a crush washer from somewhere which has managed to get in there. Hopefully the good DR @Murdo may be able to cast some light your way.
     
  5. Wozza

    Wozza Active Member Premium Member Contributing Member

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    copper/brass means bushes so Id be checking the gearbox and any where else bushes are used..shell bearings can be coated copper/brass
     
  6. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    Is it copper/brass? Or is it tiny bits of clutch plate? Hard to tell from your pics, but are there grooves in your clutch basket? Might be causing bits to break off plates when clutch is being used. Just a thought.

    Clutch.jpg
     
  7. Murdo

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

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    Have been thinking about this all day. I have looked through the resources to remind myself of what bearings are in these and all gearbox shafts use ball bearings and steel thrust washers. Has this engine been apart before and those bits may have been left from a previous problem? You say that you used a cheap gasket and the engine had oil problems. I think that the copper bits have got to come from one of the crankshaft bearings, and when you split the cases I think you will find the left side main might be your problem.
    I hope I am wrong for your wallets sake, but those bits definately look to have come from a crank bearing.
     
  8. Xavier492

    Xavier492 Member Premium Member Contributing Member

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    I forgot to follow up this post, but it was #3 conrod - big end bearing. Inside the bearing is some bronze/copper than got squashed out.
     
  9. Xavier492

    Xavier492 Member Premium Member Contributing Member

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    @Linkin I got the aliexpress pistons and they weigh 3g lighter than the factory pistons. Also I could only source 2KR engine parts and their conrods are 2g lighter (B-stamp).
    All up, that is a reduction of 20 grams across all four cylinders.

    Did you weigh the AHL pistons before you installed them, and did it affect the balance of the engine?

    My original pistons are intact (except a chip in one below) so I could possibly re-use them to stay closer to the factory weight. I asked the scrappy to weigh a 2KR piston and he reckons it says 77 grams on his scale. 2d919345223812f2219438f331f70155.JPG
     
  10. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    No but I ordered 3LN pistons & rings... 2KR stuff will probably have different dimensions as they have different part numbers.

    I would be very careful and check the piston to valve clearance, and whether the piston skirts clear the crankshaft counterweights.

    My late model 3LN6 did #3 also - some mechanical genius had installed the rod facing the wrong way and the cap in the correct orientation.
     
  11. TonyZXR

    TonyZXR Active Member Premium Member

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    Could always get the full rotating assembly balanced
     

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