/ Register

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

Rebuilding 2kr FZR engine

Discussion in 'Yamaha 250cc In-Line 4's' started by risky, Feb 7, 2014.

Page 3 of 4
  1. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    ruckus, looked at the bores and i reckon 1mm overbore would be max. how about a fzr400 in a 250 frame?to overbore what you want there would be no waterjacket. thought of air cooled barrels?
     
    risky, Feb 25, 2014
    #41
  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,111
    Likes Received:
    3,478
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    That article on No 4 big end suffering from oil starvation emanated from BDK in the UK.
    http://www.bdkraceeng.co.uk/
    http://www.bdkraceeng.co.uk/Bike1.html
    If anyone knows their FZR400s it is these guys. It seems that the 250 has similar issues. If you have an engine apart it is an ounce of prevention that should not be ignored.
     
    • Like Like x 1
    maelstrom, Feb 25, 2014
    #42
  3. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,247
    Likes Received:
    1,425
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    ruckusman, Feb 25, 2014
    #43
  4. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    mate, to start with you would have to make siamese barrells and water flow would be affected.then a special head gasket and base gasket. then special order pistons and rings.. max overbore would be 1mm on present barrells.fzr 400 is probably a factory version of your idea and i like it. never seen a 400 but would love to see if would fit.

    just got reply from china on derestricted cdi.....110 usa $ delivered by ems to aus. interested as if we got a few might get cheaper price.

    ruckus, 250 motor has 48mm bore and 34.5 mm stroke........400 has 56mm bore and 40.5 mm stroke.think outside the square. also all the cdi,s are restricted.
     
    Last edited by a moderator: Feb 25, 2014
    risky, Feb 25, 2014
    #44
  5. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    ordered a cdi.
     
    risky, Feb 25, 2014
    #45
  6. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,111
    Likes Received:
    3,478
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Which one Risky?
     
    maelstrom, Feb 25, 2014
    #46
  7. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    one for a 2kr but they had others for different models.evidently while i can hit 20g in neutral they can only do 17g in gear.
     
    risky, Feb 25, 2014
    #47
  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,111
    Likes Received:
    3,478
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    maelstrom, Feb 25, 2014
    #48
  9. Willrcr15

    Willrcr15 Well-Known Member

    Messages:
    549
    Likes Received:
    399
    Trophy Points:
    373
    Joined:
    Nov 11, 2013
    Gender:
    Male
    Location:
    Newcastle
    My Bike:
    FZR250 3LN 89
    What do you mean by restricted ?
    Mone does 18k easily, thats enough for me ! Thats a crazy lot of rpm
    Mines got a 91 engine in it does that make any difference, was there a restriction on earlier models,
     
    Willrcr15, Feb 25, 2014
    #49
  10. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    thats the link.will, the jap bikes were restricted to 180 kmh and a max of 45 hp.with standard gearing that is 111.8 mph.i am chasing power. the early fzr put out 43hp, later 45 and i will say 92 it was dropped back to 40hp.i am not worried about motor life,,, just grunt. stripdown is next week. already regretting not getting the 1mm overbore kit.
     
    risky, Feb 25, 2014
    #50
  11. Willrcr15

    Willrcr15 Well-Known Member

    Messages:
    549
    Likes Received:
    399
    Trophy Points:
    373
    Joined:
    Nov 11, 2013
    Gender:
    Male
    Location:
    Newcastle
    My Bike:
    FZR250 3LN 89
    Where does the extra power come from? When I was at 'Sporstcycle" yesterday asking about the suspension I asked what they had been able to do to the FZR's in the past & there wasn't much apart from making sure the EXUP was set just right all the time. Interestingly he talked about leaking carby rubbers, just what we have been through, the old chugging at the lights, he said they found the 'clover leaf seal' I think he means the seal on the base of the jet housing was a problem, I suggested the inlet rubber seal & he agreed but to a lesser degree.
    I had a look at the Link but no CDI for the 3LN's, unless something else fits it ?
     
    Willrcr15, Feb 26, 2014
    #51
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,247
    Likes Received:
    1,425
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1

    From some reading I've done, the 400's and 600's share and can swap quite a lot of engine parts, cases, cranks etc. There is a recipe for a 400 ->560 overbore using 600 barrels & pistons - Though I've no actual experience of any of that.

    400 barrels & pistons, perhaps longer rods to get deck height correct with longer barrels -> then need longer camchain, would be good to go to larger valves from 400 or 600, port & flow head, larger carbs, modify the exhaust

    Stock 400 piston weight might be a deal breaker knocking the redline down too far, however there are other racing pistons for various other 400's, RVF, VFR etc - but there's a lot to cross reference - pin diameter, compression height, piston crown shape, maybe re-cut valve recesses, then compression ratio etc etc.

    I could see all of this getting very expensive very quickly

    Looks like it was more an idea to keep me entertained during the rainy days, which it did very well

    peace out
     
    ruckusman, Feb 26, 2014
    #52
  13. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    come on...you might be able to stretch to 1.5mm overbore.
     
    risky, Feb 26, 2014
    #53
  14. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,247
    Likes Received:
    1,425
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    1.5mm overbore get an increase in capacity of 6% - nice if that translates to power output
     
    ruckusman, Feb 26, 2014
    #54
  15. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,247
    Likes Received:
    1,425
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    I may try putting a thicker o-ring beneath the slide insert to tighten the jet housing more effectively.
     
    ruckusman, Feb 26, 2014
    #55
  16. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,111
    Likes Received:
    3,478
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Glenn,
    Just try tightening the nut further first. Fitting a thicker o-ring will make it quite difficult to get the slide housing to fit flush with the carb throat.
    cheers
    Blair
     
    maelstrom, Feb 26, 2014
    #56
  17. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,111
    Likes Received:
    3,478
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    I don't know what the 250 uses to tighten the jet housing assembly but the 400 uses a partially hollow brass screw and it can shear quite easily. It is best to push the slide housing down firmly as you tighten that screw to relieve the tension being placed on the screw.
    [​IMG]
     
    • Like Like x 1
    maelstrom, Feb 26, 2014
    #57
  18. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,247
    Likes Received:
    1,425
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    same system on the 250 - there wasn't much tension on the nuts though when I reassembled everything and got the slide housing aligned with the venturi bore in the carb throat.

    At any rate it's worth checking again for a good dependable seal
     
    ruckusman, Feb 26, 2014
    #58
  19. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,929
    Likes Received:
    6,720
    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
    Ive read of a few cases of breaking off those nuts .... as u mentioned Blair, I put the heavy pressure on the housing and went easy with the nut.
     
    GreyImport, Feb 26, 2014
    #59
  20. Willrcr15

    Willrcr15 Well-Known Member

    Messages:
    549
    Likes Received:
    399
    Trophy Points:
    373
    Joined:
    Nov 11, 2013
    Gender:
    Male
    Location:
    Newcastle
    My Bike:
    FZR250 3LN 89
    I broke a nut, easy to do.
    They are available, I got 2 so I had a spare.
    The carbies are perfect now with the Lite Tek kit, your mad if you don't do it.
    My fizzer is going like new, in fact with a bit of use now, she's getting better, starts straight up even after a week in the shed, warms up nicely & she's got that beautiful sharp howl as she disappears away into the distance & the report on how she went is always good upon return home, can't wish for better.
    Moving on to the next headache, a worked gsxr !
     
    • Like Like x 3
    Willrcr15, Feb 26, 2014
    #60
Page 3 of 4

Share This Page