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xj650 top end on xj/fz600 ?

Discussion in 'XJ Modifications' started by pblythswood, Apr 28, 2015.

  1. pblythswood

    pblythswood New Member

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    Hi all, first post so be gentle..

    Currently have a 1986 FZ600 ( same engine as xj600 bar inlet cam I believe ) in race trim and doing the parade lap at this years IOM classic TT ( ex TT racer ) love the bike but would like some more power.

    Wiseco used to do a big bore kit which is now discontinued so was wondering if the top end off the xj650 would fit .

    Any help advise appreciated.

    Thanks
    Paul
     
  2. FtUp

    FtUp Well-Known Member

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    that's a great idea, making it breathe better to get more performance. initially, without checking specs or measuring engines, I think the cylinder spacing is different. i.e. the 650 cylinders are spaced farther apart than the 600's.

    FU
     
  3. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    The XJ650-up engines (including heads, jugs, carbs, etc.) are physically much larger (wider) than the 550/600 engines.
     
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  4. FtUp

    FtUp Well-Known Member

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    your best bet would be to port and polish the head and regrind the cams for more lift and duration.

    FU
     
  5. KDub

    KDub Member

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    The FZ600's biggest drawback power wise is the carbs. They're the same size as the FZ400's because the XJ600's wouldn't fit in the frame. I can't remember the exact bores for each set off the top of my head, but it may be possible to get your carbs re-bored to the larger size.

    Then as FtUp says, port/polish head and regrind cams. Make sure you can get the gaskets ahead of time though.
     
  6. pblythswood

    pblythswood New Member

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    Thanks all the replies much appreciated.

    I'm already doing the head/cams etc etc but there's no substitute for cc's so as the motor would be down wanted to up the capacity..believe it or not after all this time found a wiseco 652 kit in France, so going to get that , so should make it a bit livelier. Also there's a company in the uk that'll make pistons so going to get some copies made just in case it goes bang !

    What we've done so far is reemed out the carbs rubbers as they'd shrunk, modded the air filter, dynojet kit and much time on the dyno and it's upped the power from 52 to 59 ..chassis wise I've had a custom shock built, 10 mm overlength which raised the ride height by 30mm, reworked the forks and dropped them by 4 mm in the yolks and running am22/am23 tyres.. now turning in some very fast lap times, but 59hp is pretty tame for a circuit as long as the TT, so hopefully get some additional power done by August.

    Thanks again,
    Paul
     
  7. Thrasher

    Thrasher Member

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    What company are you getting the pistons from? I want to do the same on my FZ motor.
     
  8. MattiThundrrr

    MattiThundrrr Not a guru

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    please Please PLEASE get a goPRO and post video of the tt ride. greatest race in the world! Closest thing over here is the Targa Newfoundland, and it's cars only.:(
     
  9. pblythswood

    pblythswood New Member

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    Ok, will do, although don't expect it to be as fast as last time I raced there, which was in 1989 !! Got around at 110 back then which was a pretty fast lap in 1989. I'll dig some photos out and post them.

    Also, if anyone is interested I'm going to be getting some close ratio gears for the fz made which will obviously fit the xj as well. Now they won't be cheap as they'll be custom made, but mail me if anyone is interested as they'll be cheaper if multiple orders,.

    Same as above but this time for pistons, looking to get some made, 652, but going to try Wiseco first if they will produce a limited run again, as I did hear that they will if a minimum of 12 ordered, so same here, let me know anyone interested.

    Regards
    Paul
     
  10. Thrasher

    Thrasher Member

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    Paul I am interested in the pistons. Tell me more about the gears.
     
  11. pblythswood

    pblythswood New Member

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    Hi Thrasher, gears will be from Nova, see link and they're highly regarded in the classic racing world. They've not done any before for the FZ so I'll have to pay design costs as well as costs of the gears, obviously the more people who are interested the cheaper they'll be, that said I'm getting them done anyway.
    I'll be going for the conversion kit rather than a full close ratio box. Typically if they can, they'd bring 1st,2nd and 3rd closer together and drop top.

    I'm giving them a bottom end to play with around August/September as that's when they have some time to evaluate. just to confirm this will be for the 86 fz/xj 600's.

    Also if I can't get any pistons from wiseco I'm going to try these guys

    http://www.jepistons.com/

    http://www.novaracing.co.uk/YamahaClassics.html

    Tried a conversation to you but said inbox full.

    Regards
    Paul
     
  12. Thrasher

    Thrasher Member

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    I emailed Gregg at Ross Pistons back in April and he said they can do the job and said nothing about minimum order.
    If you want to get the ball rolling email him for specs and so forth. Please keep me in the loop I am ready to freshen up the old FZ600 motor.

    Gregg Suyenaga <gsuyenaga@rosspistons.com>
    Apr 20
    [​IMG]

    to me
    [​IMG]
    We would have to custom make these pistons.

    When replying back please include all original emails.

    Thanks!

    Gregg Suyenaga

    Automotive Piston Technical / Sales

    Visit our website @ www.rosspistons.com


    625 S. Douglas St.

    El Segundo, CA90245

    P: (310) 536-0100

    F: (310) 536-0333



    From: John Westcott [mailto:rocketmoto346@gmail.com]
    Sent: Monday, April 20, 2015 9:25 AM
    To: sales@rosspistons.com
    Subject: Yamaha FJ-FZ600 BB pistons


    Can you provide a Big Bore piston kit for my Yamaha 600? 1994 FJ600 and the 1988 FZ600 have the same air cooled motor. Wiseco made a kit back in the day but not any more.

    Thanks for your time,

    John Westcott
    865-235-8571

    [​IMG]
    John Westcott <rocketmoto346@gmail.com>
    Apr 20
    [​IMG]

    to Gregg
    [​IMG]
    How much would it be with rings and all?
    [​IMG]
    [​IMG]
    Gregg Suyenaga <gsuyenaga@rosspistons.com>
    Apr 20
    [​IMG]

    to me
    [​IMG]
    Assuming that you are asking domed pistons.
    Pistons - $ 440.00
    Pins - $ 50.40
    It takes 3-4 weeks to make.

    When replying back please include all original emails.

    Thanks!

    Gregg Suyenaga

    Automotive Piston Technical / Sales

    Visit our website @ www.rosspistons.com


    625 S. Douglas St.

    El Segundo, CA90245

    P: (310) 536-0100

    F: (310) 536-0333
     
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  13. pblythswood

    pblythswood New Member

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    Hi, see link, did the parade on the 31st August. First ride there for 26 years so a little rusty !!! The little fz ran like a watch.

     
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  14. Thrasher

    Thrasher Member

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    Wow! that was mega, a man after my own heart. Well did you get the pistons from Ross?
     
  15. MattiThundrrr

    MattiThundrrr Not a guru

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    Jeeeez! there's a point at around 9 minutes where he's at WOT for like 30 seconds! That "track" is awesome! A twenty seven minute lap! Madness!
    Far more passing than getting passed, nice work sir!
     
  16. pblythswood

    pblythswood New Member

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    Hi Thrasher, have PM'd you a few times but no response so thought I'd use the forum in case my mails are in spam ..

    So chaps, on the piston/big bore options have found that a kawasaki z650 or kz650 ( in US ) piston is almost identical to the fz/xj, but is a 62mm piston, ( same pin size, same crown height, just slightly different dome shape so in the next week or so will measure the motor to see if there is enough room to re-line the barrel, be looking for around 2mm minimum thickness, I'll let you all know if it's pheasible, but as wiseco did a 61mm piston in the standard liner then there's a fighting chance.

    Regards
    Paul
     
  17. Thrasher

    Thrasher Member

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    Hi Paul, sorry I haven't got back to you sooner. That's good news if its true, Weisco still offers the kit for the GPZ550
    I don't know why they wont have a fitment for us. Is the pin location is correct. My tuner from way back bored the 550 cases to except bigger liners.
    Some how he sourced out some Honda pistons that brought it up to 650cc. Maybe the thing to do is get a used piston from the KZ and the FZ from ebay
    and have my machinist look at them. He is the same one that cut the valve pockets on the Honda pistons.
     
  18. pblythswood

    pblythswood New Member

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    Already have the pistons, so have a look at the photos, almost identical, KZ 62mm piston on the left and FZ 58.5mm piston on the right.
     

    Attached Files:

  19. Thrasher

    Thrasher Member

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    Looks good I guess you are on to something. Keep me informed.
     
  20. a100man

    a100man Well-Known Member

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    Hi Paul

    This is great info - I spent quite some time looking for O/S pistons for my YX600 (like XJ) engine as the bores were pitted due to water ingress - In the end I had to settle for a ream and new rings but one pot is down on compression as a result (135 vs 150). I was looking at the 60mm range which maybe why I overlooked te kwak stuff. Do please keep us informed about the rebore.

    Cheers

    JS

    PS here's my ride at this years TT in June. I am but a humbled spectator however..
    20150605_134727[1].jpg
    PPS What was your bike in 89 ? 110 is mighty impressive
     

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