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Project My '90 FZR250 3LN3

Discussion in 'Your 250cc Projects' started by my67xr, Jun 19, 2016.

  1. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    Yeah you could use the 3M Clean and Strip disc's or Flexovit FlexiStrip disc's on a 7" Sander/Buff, they are pretty good and leave a fine smooth finish, you can get them from 50mm o/d and up.
    Some are 50mm or 75mm Roloc quick connect fitting for using on an arbour in your die grinder, there's disc's on a spindle for using in a drill, then you get the 4" and 5" disc's for an angle grinder, , and bigger 7" one's for sander/polisher's
    You can get them in various grit's too
    Slower speed's in your power tool will leave the metal you've scoured with a slightly coarser finish rather than a polished finish, even scuff them with some 320g W&D paper after you're done to leave a better finish for the paint to adhere to.
    If you haven't used them before be careful on edge's the disc's can grab and rip them apart if you are doing it a high speed.
    Get some good 3M green or grey Scotchbrite pad's for getting into the fiddly area's too, best place is an Automotive Crash Supplys store, and most hardware store's keep them too now

    roloc%20.png scotch-brite-roloc-clean-and-strip-xt-disc-3-inch-pn-07476.jpg roloctm-plus-holder-2.jpg images?q=tbn:ANd9GcRZhyzS-WURA7Ld_7UypF9DyyqAkfxCovEQUAJflwfOQAdojLCD.jpg

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    Last edited: Jul 24, 2017
  2. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    My new/used intake manifold's arrived from Japan today.
    They aren't the best condition, but they're still better than mine.

    Before i bought them i messaged the seller -

    Hi,
    i'd like to buy these manifold's,
    is there any cracking at all on them?
    eg when you move the rubber where the carburetor fit's etc
    My set has fine crack's and it leak's air into the intake system

    His reply-

    Thank you for your inquiry.
    I believe it's not turn off at those rubbers because we don't note any additional description about damage, cracks or torn off part.
    Thank you again and good luck!
    Mariko

    I think he meant to say that he doesn't know, because he never looked closely at them, and good luck if they are cracked !
    2x boot's had crack's about 15mm long on them and are maybe .25mm - .5mm wide

    I gave them a smear of Urethane, opened up the crack a little by bending the manifold's and rubbed it into the crack's, then smeared some over the top
    I reckon they should be good now.


    While i had the carby's off i pulled them down again and cleaned them up with degreaser then carby cleaner.
    I stripped each carby and removed all the jet's, including the mixture screw's etc, then poked a single strand of copper wire through everything again and blew out all the port's etc
    Set the mixture screw's to 2.5 turn's out, it wouldn't start without a dribble of fuel down into each carby so i tried the mixture screw's at 3 turn's out and was still the same.
    I turned them out to 3.25 turn's and it started and idled but i needed to hold the throttle open a touch.
    Opened the choke a little and it would idle for a minute or so then die.
    After a couple of minute's it was warm enough so it would just idle, i put the temp gun onto the pipe's and got a reading of 125° C on pipe #1, 127° C on pipe #2, 60° C on pipe #3, and 125° C on pipe #4.
    I am going to have to check carby 3 out again i guess

    Will have to check the carby sync and float level's too i think, carby 3 might have the butterfly closed up or closed more than the other 3 maybe or the float level might be too low ?


    20160713_163017 (1).jpg 20160713_163217.jpg 20160713_163200 (1).jpg 20160713_163230 (1).jpg 20160713_223355.jpg
     
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    Last edited: Jul 24, 2017
  3. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    At least they're clean! I had trouble with my zeal set having fuel pour up out of idle air jet on cylinder 1. I adjusted the float height after inspecting the float needle, which had no wear.

    While you have them off, flip carbs upside down and sync 1 & 2 butterflies. Check the sync when closed and wide open. Then sync 3 & 4. Then adjust the middle sync screw until all 4 throttle bodies are synced when wide open and closed.

    Then you just need to break out the laser thermometer and adjust the idle fuel mixture for each carb :)
     
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  4. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I had another play with the carby's today, spent about half an hour tuning them better with the temp gun
    Best i can get all 4 carby's is around 160° C , not sure why i can't get them up around 250° C like Linkins' ?
    Bike start's easier again now, and i can finally use the choke too

    I thought i'd have a look at the clutch too, i made up a good set of friction's and steel's from the best of the spare engine and mine and have fitted them.
    The basket has some nice groove's in it though so now i have to remove that and file them back unless i can find a good one somewhere
     
  5. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Did you have the bike warmed up? I did mine after coming back from riding around town. I got cylinder 1 up to a consistent temp, but cylinder 3 was still above 260c after adjusting the fuel screw twice. Might be tight valve clearance

    Measuring the temperature as close to the exhaust port as possible will give a more reliable reading.
     
  6. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yeah the bike was warm, over half on the gauge, i had it idling for 30 min's while i was adjusting the carb's, fan was coming on every now and then too.
    I had one pipe up to 190° at one stage but it was idling at about 1800 rpm
    I took the reading at the top of the pipe's just under the flange where it bolt's to the head
    I can't ride it atm with the clutch, might try swapping the spare clutch cable in the original might be stretched but i don't think it will make much difference because there is still adjustment left at the lever
     
  7. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Airbox on? All I can think of.
     
  8. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yeah, on and sealed well, no leak carb's to manifold either
     
  9. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    I made up a clutch basket tool to hold it while i undid the nut, used a couple of cooked steel plate's from the spare engine and welded a bit of scrap steel on for the handle
    Work's just like a bought one.

    If anyone want's their own tool i can make them up easy enough, i just need a couple of old clutch steel plate's and about half an hour or so to make a handle and weld it on.
    I'll do them cheap for forum member's


    I had a practice on my spare engine removing the basket first


    Fit tool on clutch hub so it can be held to loosen the hub retaining nut

    20160716_132258.jpg 20160716_132307.jpg


    Bend back the tab on the washer behind the nut to allow the socket to fit on, use a 6 point impact socket to undo the nut if you have one (less chance of a 6 point socket slipping and rounding off the nut)

    Clutch hub removed, with locking washer and 24mm nut

    Remove bearing carrier and bearing and once the clutch hub is off remove the bearing thrust plate

    Align shorter leg's with middle of case to allow enough clearance to remove the flywheel/basket from the crankcase

    Basket / flywheel removed, ready to file flat the ridge's that have been worn from the clutch friction plate outer locating tabs
    Filing it back will cause a little noise from the clutch friction plates' tab's chattering in the basket but i can't do anything else unless i find a new or good basket
    You can usually get away with this repair just the one time

    20160716_132407.jpg
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    20160716_132307.jpg
     
    Last edited: Jul 30, 2017
  10. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    Here's the basket/flywheel off my bike, the new tool made it simple to get off

    This kind of show's the groove's worn by the friction plate's, not too good pic's

    20160716_144037.jpg 20160716_144044.jpg

    I draw filed them lightly with a coarse file, only took a few stroke's to clean them up 80%, then went over them with a fine file to smooth them out
    The angle of the slot's allow's you to use the file flat and straight and file's both side's of the basket at once.
    I held the file in the centre of the basket and just moved it back and forth a few time's to file it back, this stop's you from changing the angle's if you were to file each slot individually

    20160716_151425.jpg
    These pic's show the .5mm or so clearance after filing each leg


    20160716_151452.jpg

    20160716_151504_001.jpg
    Finally finished off by deburring the edge's with some 180 grit paper, then thoroughly clean it ready for refitting

    20160716_150835.jpg
    And here it's all clean, degreased then blown off with the compressor

    I also checked the rubber buffer's between the flywheel and basket as i have found problem's caused by them failing on some bike's, these are all good.

    20160716_153704.jpg 20160716_154753.jpg 20160716_154740.jpg
     
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    Last edited: Jul 27, 2017
  11. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Front plate has to be lined up with the arrow on the front

    C 6 mark.jpg

    Spring bolts need to be carefully torqued ..... 6nm ..... seen a few like this .....

    broken plate.jpg
     
  12. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Clutch is back on now and feel's a lot smoother than it did before filing the basket
    Yeah i worked out it only goes together one way, and the bolt's are torqued up with a 1/4 drive screwdriver
    I have the adjuster done up till it just touch's then backed it off 1/4 turn and did up the lock nut
     
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  13. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    The clutch friction plate's are 3mm thick measured at 3 or 4 spot's on each, the steel's are 2mm minimum and none are warped.
    The adjuster is done up till it touch's then backed off, then done up till it just touch's again then backed off 1/4 turn, the locking nut is done up while holding the adjuster still
    Clutch lever has 3mm play before starting to feel resistance, tried it with 1omm play and over tightened, bike still stall's into gear

    I'm thinking that backing off the adjuster 1/4 turn isn't enough ?
     
  14. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    really nice work on the clutch basket holding tool :bowdown:
     
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  15. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Nice work, yet again.
    My 400 has a cage inside the sprocket cover with 1/8 balls in it. The balls were crapped out and dry. If the 250 has a similar setup you could be losing some axial travel.
     
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  16. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I have tried re-oiling the clutch plate's too.

    The only ball bearing in this clutch is the 8mm one inside the gearbox main
    shaft where the clutch adjuster screw does up against
    It still look's in good condition with no wear or flat spot's etc



    There's a needle roller bearing inside the clutch basket/flywheel section, but i oiled that when i put it back together
    That cant move in or out once the hub retaining nut is done up


    20160716_201822.jpg 20160716_201558.jpg
     
    Last edited: Jul 24, 2017
  17. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Did u put the spring and skinny fibre back this way?

    clutch plates 2.jpg
     
  18. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I did the first time, with the recesses in the steel's facing the washer too.
    Tried moving the narrow friction plate and spring to the middle of the pack too, still no change
    I have deleted that narrow friction plate and spring now, just have another good standard friction plate, like what you do when you get a new clutch friction plate kit
    All i can think of is the new/used plate has been sitting for age's before i fit it, it may have lost a bit of absorbed oil, but it was covered in oil when took the spare clutch apart
    I've taken them all out again and have them soaking in Castrol 4T oil, will try reassembling it again tomorrow morning
     
  19. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    I bought an EBC SRK series clutch kit for the FZR250R and it included the skinny friction plate. Never had any issues, but I didn't mess with the adjuster rod length... only the cable adjustment on both ends... spec for the rod length should be in the service manaul.
     
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  20. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yeah probably is but i cant read Japanese,
    Clutch in Japanese is Kuratchi クラッチ, been searching in the mechanical section of the manual for any setting's
     

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