/ Register

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Project FZR fix up

Discussion in 'Your 250cc Projects' started by Yetiburger, Oct 7, 2017.

Page 25 of 25
  1. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,959
    Likes Received:
    6,747
    Trophy Points:
    1,168
    Joined:
    Jun 14, 2012
    Gender:
    Male
    Occupation:
    Between a Rock and a Hard Place
    Location:
    North by NW NSW Oztralia - Tamworth
    My Bike:
    *Kawasaki ZXR250C *Yamaha FZR250R 3LN1 *Yamaha FZR400 *Triumph Bonneville 750 T140V *Triumph Daytona 675 *Triumph Tiger 800XC
    ZXR discs have it but never seen it on an FZR

    3LN7 specs

    3ln7 brake spec.jpg

    3LN specs

    3LN specs.jpg
     
    • Like Like x 2
    GreyImport, Dec 3, 2021
    #481
  2. Linkin

    Linkin The Mechanic - Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,854
    Likes Received:
    2,999
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    Wear limit for discs is usually 0.5mm from new.

    You can figure out the original thickness of the discs by measuring either the inside or outsite lip of the disc where the pads don't run (and make it difficult to remove calipers when the disc is worn out) vs the thickness at the thinnest section - usually the centre of the pad surface.
     
    • Informative Informative x 1
    Linkin, Dec 3, 2021
    #482
  3. neoncrypnid

    neoncrypnid Well-Known Member Premium Member

    Messages:
    170
    Likes Received:
    55
    Trophy Points:
    213
    Joined:
    Feb 23, 2020
    Gender:
    Male
    Location:
    Australia
    My Bike:
    FZR250 2KR
    My 2KR (single disc) had 4.5mm stamped on it. Can't say for sure what the 3ln limit is

    Sent from my SM-G991B using Tapatalk
     
    • Informative Informative x 1
    neoncrypnid, Dec 3, 2021
    #483
  4. Yetiburger

    Yetiburger Well-Known Member

    Messages:
    226
    Likes Received:
    63
    Trophy Points:
    213
    Joined:
    Sep 11, 2017
    Gender:
    Male
    Location:
    Whanganui, New Zealand
    My Bike:
    yamaha fzr250 3ln1 x2 , Sv1000s
    So I got the bike back on the road early January.
    Its all legal with a WOF and Reg.
    Also did a rider training day at my local track. bike did bloody well having the tits reved out of it next to race bikes and pennagales etc.

    Have found I may need boots with toe sliders.
    image.jpg 20220126_083632.jpg
     
    • Like Like x 2
    • Winner Winner x 1
    Yetiburger, Jan 31, 2022
    #484
  5. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,959
    Likes Received:
    6,747
    Trophy Points:
    1,168
    Joined:
    Jun 14, 2012
    Gender:
    Male
    Occupation:
    Between a Rock and a Hard Place
    Location:
    North by NW NSW Oztralia - Tamworth
    My Bike:
    *Kawasaki ZXR250C *Yamaha FZR250R 3LN1 *Yamaha FZR400 *Triumph Bonneville 750 T140V *Triumph Daytona 675 *Triumph Tiger 800XC
    They let u on track with those?
    I would have thought laces would be a no no

    Good to hear the ol FZR did its business :thumb_ups:
     
    • Like Like x 1
    • Agree Agree x 1
    GreyImport, Jan 31, 2022
    #485
  6. Yetiburger

    Yetiburger Well-Known Member

    Messages:
    226
    Likes Received:
    63
    Trophy Points:
    213
    Joined:
    Sep 11, 2017
    Gender:
    Male
    Location:
    Whanganui, New Zealand
    My Bike:
    yamaha fzr250 3ln1 x2 , Sv1000s
    Well gents the FZR served me well for a good while. I got it back on the road and got all my licensing done.
    It was starting to smoke a bit but still ran great. To be fair I've let it sit for a good few months with crap gas and it still starts straight up and runs mint. Unfortunately once she's warm there's a not very nice sound coming from in the engine (too long dealing with an overweight under talented rider).
    I thought hopefully it might have been the timing chain, but after talking to a couple of people I think it may be a small end, hard to tell. I'm thinking of stripping the engine down as it could probably do with some rings.

    What are the main troubles I would have trying to get the engine back together?
    No rods available?
    Rod bolts?
    Timing chain?
    valve stem seals, head gasket?
    I would love to give this engine a birthday as I think its an awesome wee bike, and I love a project.
    Any advice or experience welcome.

    If I pull it apart I will take photos and keep you updated.
     
    • Like Like x 1
    Yetiburger, May 25, 2023
    #486
  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,329
    Likes Received:
    1,474
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    If the small end is going, then check Impex for rods.

    Rod bolts are solved - Use Kawasaki ZXR250 ones - they're a great fit, tested personally - either Impex or Webike.

    Timing chain is readily available.

    I'm about to do some minute measurements of both new Aliexpress bearing shells and new OEM bearing shells - will do a writeup of the technique so that anyone can do it themselves with either a dial indicator or a micrometer.

    Lots to decode [which I've done] as Yamaha don't give bearing material thickness for the various colours - BUGGERS!

    Valve stem seals - aliexpress, make sure they're for a 3LN as the stem size is different [3.5mm] -v- the 2KR which is 4mm
    Head gaskets are available OEM new ~$35AUD - any Yamaha dealer should be able to source one.
    Reuse the base gasket, apparently the aliexpress one is not metal.

    FYI I just got a set of 48.25mm O.S. aliexpress pistons and rings - they're quite good, need some deburring with an emery board but all other measurements are on spec [there are one or two differences in the which aren't of any consequence], including the rings which do actually have a 0.01 thickness difference between the the top and 2nd rings, which is on OEM spec.

    I also purchased some aliexpress rings, 48mm [which I was going to use before deciding to go for a rebore], which all measured up on spec also.

    BTW before you tear it down, how are your valve clearances?
     
    • Like Like x 1
    Last edited: May 27, 2023
    ruckusman, May 25, 2023
    #487
  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,174
    Likes Received:
    3,537
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Apparenty it is not uncommon for FZR 250's that have been raced, to destroy a bigend bearing, cylinder 4 as I recall. Well at least there have been several cases of this reported here. We have never gotten to the bottom of this because the owners never try to fix it or post photos and details. They just go and buy another engine and blow that one up. Now what was it about doing the same thing over and over again and expecting different results? Because it has always been cylinder 4, us forum sleuths have been suspicious about oil feed issues and discussed this at some length.
     
    • Agree Agree x 3
    maelstrom, May 25, 2023
    #488
  9. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,329
    Likes Received:
    1,474
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    I think Cylinder 1 can also be vulnerable.
    I reckon that's caused by two or more factors, as @gregt identified, the lack of a good chamfer on the crank itself, potentially the restrictors coming loose, the oil gallery changing size [smaller] in the feed to the crank AND the oil pressure release valve coming in at very close to the peak oil pressure at high revs.
     
    ruckusman, May 25, 2023
    #489
  10. Linkin

    Linkin The Mechanic - Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,854
    Likes Received:
    2,999
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    I seem to recall discussing the viscosity of the oil being used coming into the equation as well... Pressure is resistance to flow, if the oil in use is thicker or thinner than the specified one to use then it it will affect both flow and pressure, potentially causing problems. So use the correct viscosity for the temperature range.

    On an FZR I have never personally seen wear caused by using too thin an oil... just mostly from neglecting to use any oil at all until the stuff that's in there is a black watery mess full of carbon and acidic combustion by-products.

    So I would say run the highest quality lowest viscosity you can get away with. Given that the machine we are dealing with is not an air-cooled underpowered lump hampered by a frame weighing 500kg, 20w50 would not be appropriate.

    I'd probably go with a 10w40 or a 15w40 like the Delo 400 that everyone raved about.
     
    • Agree Agree x 1
    Linkin, May 25, 2023
    #490
  11. Yetiburger

    Yetiburger Well-Known Member

    Messages:
    226
    Likes Received:
    63
    Trophy Points:
    213
    Joined:
    Sep 11, 2017
    Gender:
    Male
    Location:
    Whanganui, New Zealand
    My Bike:
    yamaha fzr250 3ln1 x2 , Sv1000s
    I did all my valve clearances not long ago in terms of kms. However it was mentioned that the shims may be quite thin that I was putting in? the clearances were quite varied from memory. The bike has seen a couple of big track days which were awesome.

    While shoving my nose in and diagnosing it I did notice blowby coming passed the bloody cam cover bolts, so I think at a minimum the engine needs pulling and a good going over, probably a set of rings.

    does any one have a link to the engine critical measurements? big end, main etc.
     
    Yetiburger, May 26, 2023
    #491
  12. Yetiburger

    Yetiburger Well-Known Member

    Messages:
    226
    Likes Received:
    63
    Trophy Points:
    213
    Joined:
    Sep 11, 2017
    Gender:
    Male
    Location:
    Whanganui, New Zealand
    My Bike:
    yamaha fzr250 3ln1 x2 , Sv1000s

    Thanks Linkin, I believe I was using 10w 40 Motul but I will check when I get home.
     
    Yetiburger, May 26, 2023
    #492
  13. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,174
    Likes Received:
    3,537
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Oils Ain't Oils
    Read some test articles on motorcycle oils, the more the merrier. Here's two
    https://www.cyclenews.com/2020/05/article/how-to-select-the-correct-motorcycle-oil/
    https://www.cycleworld.com/sport-rider/oils-well-that-ends-well-part-2/
    I will use Amsoil in my project bikes, if I live long enough to see them run. As @Linkin said, change the damn stuff. Most of the engine rebuilds I had to do in my life were also of the filthy black sludge variety.
    Speaking of shells
    https://www.enginelabs.com/engine-t...earings-a-test-of-bearing-and-oil-wear-rates/
    Wouldn't it be great if we could get these for the 250 fours. I asked them what their MOQ is for custom sizes just for shits and giggles.
     
    maelstrom, May 26, 2023
    #493
  14. driftwood

    driftwood Well-Known Member

    Messages:
    106
    Likes Received:
    45
    Trophy Points:
    213
    Joined:
    May 9, 2020
    Gender:
    Male
    Location:
    melbourne
    My Bike:
    FZR250R
    I had one with a rattly top end - whacked in a Chinese chain (with trepidation, as it had 1 less link laterally). Same. I had split the cases to also check channels into main bearings (OK), but pulling maggy is none too easy.
    1. Remove the tensioner (centre bolt 1st) to see how far in the plunger is. Chains are ratsh before the limit btw.
    2. If it smokes at startup, stem seals - but really, really fiddly. $6 for the set, bewdy, but years off your life.
    3. Compression test. Then you know ya got no choice but to swap pistons (piss easy) etc. Gauge with extension hose is $28, else leakdown: hit it with >130psi and feel what's happening at the breather.
     
    driftwood, May 26, 2023
    #494
  15. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,329
    Likes Received:
    1,474
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    In the resources section you'll find:
    The 2KR service manual in Japanese
    The 3LN1 supplement - for specs the useful portions commence in section 2 - the second column on page labelled 2-1 and the first column on 2-2 primarily

    @gregt has said that for racing [track days would be included] the bearing clearances as shipped were too tight - he aims for 0.0016" [which is 0.040mm] for mains journals and 0.0018" [which is 0.044mm] for big end journals - OEM 3LN specs are 0.023-0.047mm for both

    Piston to bore clearance is 0.04-0.06mm - pistons measured on the skirt, 5mm up from the bottom
    Cylinder out of round and taper limit 0.03mm
    Most of the other specs/measurement make sense from the context on those two pages.

    The 3LN6/7 specs sheet in English - very useful
    Zeal 250 spec sheet in English - very useful
     
    • Like Like x 2
    ruckusman, May 27, 2023
    #495
  16. Yetiburger

    Yetiburger Well-Known Member

    Messages:
    226
    Likes Received:
    63
    Trophy Points:
    213
    Joined:
    Sep 11, 2017
    Gender:
    Male
    Location:
    Whanganui, New Zealand
    My Bike:
    yamaha fzr250 3ln1 x2 , Sv1000s
    So I may have a problem. But I found some parts to fix my bike. (plus enough to make another complete bike).


    Now I just need to clean the bloody shed up.
    20230729_120234.jpg 20230729_163536.jpg
     
    • Winner Winner x 2
    • Like Like x 1
    Yetiburger, Aug 1, 2023
    #496
Page 25 of 25

Share This Page