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Help FZR250r 3LN1 Project

Discussion in 'Yamaha 250cc In-Line 4's' started by PhillipFZR, Apr 13, 2020.

  1. PhillipFZR

    PhillipFZR Member Contributing Member

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    So I reconditioned my head and just finished putting the top back on the bike, and as I was swinging the bike by hand as is good practice, I couldn’t see any new oil emerge from the cams, so I pushed the bike in second gear to see if I can get the oil pressure up and emerging and still nothing, also tried it with the starter. So my question is how do I check correctly if my head is getting enough oil? Because I bought the bike with a seized cam, maybe this could be a contributing factor to why the cam seized in the first place,

    any advice would be appreciated thanx


    96C1C0B3-E99F-419A-B6B8-D69B673B9830.jpeg 188798E5-0C8C-43E0-A715-6A70975ADF46.jpeg
     
    Last edited: Apr 13, 2020
  2. Murdo

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

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    Clean oil, new filter? Sometimes it takes quite a bit of starter winding to get the oil to fill the filter and up to the top end.
     
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  3. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    When u do get it running take note that the oil light on a 3LN1 is for oil level and not oil pressure ... later 3LNs had an oil pressure sender

    3LN1 oil level sender

    oil level sendor.jpg
     
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  4. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I know I've seen an oil gallery schematic on here, I think it was in relation to the potential oil gallery mod for rod(s) 1 &/or 4 to prevent spun bearings and the knowledge for the mod originated with the FZR400

    OK, so I've found the original thread
    https://2fiftycc.com/index.php?threads/big-end-oil-gallery-mod-for-fzr400s.10366/
    It shows the lower portion of the oil gallery for the FZR400 and the upper section

    However there's this thread with the oil gallery schematic of the FZR250 image
    https://www.2fiftycc.com/index.php?...r-4-big-end-bearing-failure.6927/#post-120764

    Now I've mentioned that because if there was a buildup of varnish or burnt oil perhaps you'd be able to check the oil feed for the cylinder head for any blockages, also as the cams are their own oil feed gallery it should be simple enough to check them for flow or a blockage with a piece of aluminium welding wire fed into and through the hollows in the cams

    Another options I suppose would be to remove the cams and fill their oil feeds to see if they stay relatively full - do the FZR oil filters have a drain back prevention?

    Then repeat turning it over to see if the filled oil gallery gets the oil flowing sooner.

    Anyway, food for thought
     
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  5. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Don't forget the good doctor's advice to use rifle bore cleaning brushes.
     
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  6. PhillipFZR

    PhillipFZR Member Contributing Member

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    Ok so we ‘primed’ the cams before swinging the bike and the rubber caps popped of on all cams so we have oil pressure.. now that everything is back together we cannot get the bike to start, we have spark, we have fuel, and its seems as it has compression by feel, do you think valve clearance can have something to do with it, only thing is because of lockdown we cannot get shims, but ya, any thoughts on what we can check would be appreciated
     
  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK, we toiled with a recent new user who got a bike that hadn't been run in ages but had had the cylinder head reconditioned by the previous owner, well we tried everything and then the solution turned out to be that the inlet and exhaust cams were swapped

    Take it to cylinder 1 firing @ TDC and see where the lobes for cylinder 1 are pointing - they should both be pointing outwards as the inlets have recently closed and the exhaust will soon be opening
     
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  8. PhillipFZR

    PhillipFZR Member Contributing Member

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    So we checked the clearance, and only 6 of 16 have clearance, the rest are open, so thats a bummer, dont know where I can get shims with the lockdown, otherwise I have to figure out how to put those small shims in the lathe to cut them to size
     
  9. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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  10. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Well look on the bright side, the problem was easily solved and the guy that @Linkin has linked to is incredibly punctual with shipping, understandably it was only interstate for me, however he shipped them the day that I ordered them and they arrived on the very next day
     
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  11. PhillipFZR

    PhillipFZR Member Contributing Member

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    I know my local bike shop will have shims, so getting them isn't a problem, and ordering online wont help because of the lockdown, looks like i'll just have to be patient until 1/5/2020, that when our lockdown here in South Africa is scheduled to be over
     
  12. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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  13. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    My understanding is that the postal service is still operating, here at least
     
  14. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Yes... but International Post to south Africa??? Very few Aircraft are in the air and as such freight including Post is very much delayed.
    I am pretty sure the OP would be able to source shims over there cheaper and probably quicker than having them sent from Melbourne...
    I am still waiting on a small parcel from Melbourne that was sent on the 2nd April so our Postal Service is still as hit and miss as it ever was...
     
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  15. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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  16. PhillipFZR

    PhillipFZR Member Contributing Member

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    Just for interest sake, what is the lowest value you can shim the fzr clearances? My values does seem a bit low and i'm starting to consider grinding them just to get the bike started to get my hopes back up, sizes are as follows with the current shim size and clearance, the O is for no clearance, valve open. p.s I did make contact with precision shims and will order as soon as the lockdown is over seeing that my local shop couldn't help me with smaller sizes
    I1 = 160 = O
    E1 = 180 = O
    I2 = 170 = O
    E2 = 170 = O
    I3 = 165 = O
    E3 = 165 = 0.18
    I4 = 160 = O
    E4 = 163 = 0.15
    I5 = 168 = O
    E5 = 168 = 0.19
    I6 = 158 = 0.11
    E6 = 162 = 0.20
    I7 = 162 = O
    E7 = 160 = 0.23
    I8 = 165 = O
    E8 = 175 = O
     
    Last edited: Apr 15, 2020
  17. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK so it looks like all of the clearance has disappeared because the valve seats have been worked - precision shims list down to 1.0mm, but I doubt you're anywhere near having the springs under too little tension and it's not like you have valves cupping or seats receding into the head.

    The trick will be getting a reading on those with shims already in the low to mid 160 range with no clearance so that you know what to order if the 158 is still too thick
     
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  18. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Race Bike Service's told me when i was buying/swapping shim's with them, once you get down needing around 1.25mm shim's the valve's usually are close to replacement time

    My 3LN3 had a one or 2 shim's around 1.25mm so next time the clearance's need doing i'll be taking the head off and fixing any issue's


    You could buy a 141 piece kit from aliexpress for $86AU, a few member's have used these here
    These go down to from 3.5mm right down to 1.20mm, and you can buy them in smaller lot's too if you need too (see second link)
    https://www.aliexpress.com/item/325...earchweb0_0,searchweb201602_,searchweb201603_


    https://www.aliexpress.com/item/328...earchweb0_0,searchweb201602_,searchweb201603_
     
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  19. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    One possibility, if new valves are too expensive, and the existing valves and seats are good, is to grind the tips down. I wouldn't do it on any modern bike due to the material the valves are made with / coated with, but with old school stuff it can be done.

    The things to keep in mind are keeping enough meat there so the collets are secure and that the tips won't break off from not having enough material. This way you can restore some valve clearances and use larger thickness shims, but it's definitely a last resort / budget method.
     
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  20. PhillipFZR

    PhillipFZR Member Contributing Member

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    Like I said only thing keeping me from getting a shim kit is the lock down, So my plan of action is as follows, im have a very small lathe that has been gathering dust, im going to turn a ‘thing’ into which I can place the shim to hold it, and then machine down the shim, then mic it on the sides to see how square it is, this will still only be a temporary fix, if it works, just to get the bike started, in my mind its better than grinding down the shims
     
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