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Project FZR150 Bucket race motor

Discussion in 'Other Projects - Other Bikes (non 250's)' started by gregt, Aug 14, 2016.

  1. gregt

    gregt Well-Known Member Premium Member

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    This thread is by way of a thank you to the Admin here for allowing me to download info I needed and because it may well be of interest to some here.
    I'm a Kiwi building mainly Classic and Post Classic race engines and sometimes complete bikes for the NZ scene, specifically the South Island.
    This project - half an FZR250 - is for the NZ Bucket class rules which in this instance require around 150cc and to be based on a road motor. There are allowances but pretty well everything used in this is road based anyway.
    The concept is not original to me. A gent known as Speedpro on Kiwibiker forum has built and is slowly developing a turboed and injected version. He will ultimately have to make it legal by reducing capacity to 100cc from it's current 125cc.
    I went what i consider the easier path of taking the engine out to 150cc and running unblown.

    I laid hands on about 1 1/2 broken 250 motors...by trading parts. Luckily the required side - the right - was good on one. So, cut the crank just past the camchain sprocket leaving 3 main bearings. From this point the crank oil holes were properly radiused and the crank linished. I'm using the 3LN long rods - and keeping my fingers crossed.
    To obtain the bigger capacity, I sourced a pair of low mileage GSXR400 pistons - early 53mm bore size. The gudgeon pin size is the same as the FZR.The barrel casting was cut just past the camchain tunnel and the liners pulled. I machined up new bigger liners and a friend bored the casting to suit. I installed the liners and he finish bored them. The camchain is 2 links longer also. Straight from the DID catalogue - a GSXR400 one I think.
    The pistons are approx 4mm higher deck height so a std base gasket, a 4mm spacer plate and a copper .020in head gasket, followed by a .010in cleanup cut on the barrel gave .032in squish.

    The head is also cut to match the barrel. The cams are swapped round end for end as the location is on the missing side of the head. New slots are cut in the head for the cam location.
    The lobes are symmetrical so running in reverse direction is not a problem.
    I'm using a std exhaust cam and a reground inlet. The inlet has a grind from the local guys Kelford Cams and is about .020in more lift and around 20 deg more duration at running clearances. i've put them in on 103/104 deg lobe centers which i know works on bigger FZR's.
    The inlet is not a buildup, it came out of the std lobe. Shimming was not excessive - biggest shim used was a 260. Still plenty of room before coilbind and the retainers are a mile away from the seals.
    Once I'd established the cam timing I could look at the valve cutaways. The Exhausts just needed moving a little closer together so they were cut using a die grinder. Plenty of depth on the cutaways too. I could actually have cut the head for more compression but it measures up at 11.8:1 - that'll do for a start.
    Pistons are 20g heavier than OE, we'll have to see if it shakes.

    Sealing the cut end was always going to be a problem. The wall thickness is thin so welding will inevitably distort things. There is some filler used to get a flat end which can have a plate screwed to it. The cut ends of the cam cover have rubber channel bonded to them. This is hard up against the cover plate. Will it seal well enough, we'll see...

    Speedpro's version uses the stock waterpump exit pipe going out and around. I've changed the pump exit to a tangential one for a short hose up and across the back of the block. Bit tidier - and importantly for me, narrower.

    At this point I'm planning on stock ignition, run total loss. I've cut the stock rotor but have yet to do a narrowed ignition side cover.

    I was planning on a scratch built frame - I build frames too - but have since been offered a race prepped FZR250 chassis complete with slicks and spare wets. It is of course at the opposite end of the country...

    Got to put it aside for a while and get on with paid work. More as it progresses.


    FZR 150 twin.JPG FZR150 pistons.JPG Fzr150 head.JPG FZR150 cut end.JPG FZR150 cover plate.JPG FZR150 #1.JPG FZR150 #2.JPG
     
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  2. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Mate that's an amazing write up and modification! I'd like to see it running! :thumb_ups:
     
  3. Murdo

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

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    Kiwi inginuity at its best.
    Nice project. :thumb_ups:
     
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  4. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Yes, necessity being the mother of invention, I think the Kiwis have it in their genes.
    Keep us updated and I am sure the forum members will be happy to help if we can.
     
  5. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    That's awesome
     
  6. gregt

    gregt Well-Known Member Premium Member

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    Thanks guys. Can anyone tell me which of the manuals - the basic or the 3LN supplement - has the 3LN Exup wiring diagram ?
    I've run FZR400 Exups total loss with no problems - but I'm told you can't run the 250 version without the exup in circuit..
    And of course i don't have an exup control box - and don't want to run it anyway...
    Anyone know a way around this ?
     
  7. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Do you know what model of bike yours is, as there are a few variants. The first FZR's to have EXUP were the 1989 3HX models. Basically a 1986-1988 model FZR250 with EXUP. Then you have the 3LN1 which is also a 1989 but has the new deltabox aluminium frame. The engine has an internal oil filter in the sump, for which the headers have to be removed to access. After that you have the 3LN3/5/6/7 which all have external oil filters on the left side.

    EXUP was designed to eliminate the flat spot that comes from using a 4 into exhaust header. I would think that it wouldn't do much for a 2 cylinder FZR, but you would have more experience with that :)

    Try the 3LN1 supplement: http://2fiftycc.com/index.php?resources/yamaha-fzr250r-3ln1-service-manual-supplement.11/
     
  8. gregt

    gregt Well-Known Member Premium Member

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    Thanks for that. What I have are two ignition boxes - both believed to be exup versions. I'll throw the ID out there hoping someone can tell me what if anything are the differences..
    These were bought separately from the engines and the ignition will be built around one of them.
    One is 3LN - 82305 -60
    131800 - 5860 TNDF18 Big letter M

    The other is 3LN - 82305 - 50
    131800 - 5420 TNDF11 Big letter Q

    All the engines I have here are marked 3LN - and all have the same multi trigger flywheel. I have no idea what version frames they came from as they'd been laying in a junk collector's shed for years....
    And I have both types of sump...I've used the early one as again i wanted to narrow things as much as possible and didn't like the spin on filter sticking out the side...
     
  9. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    The engine number will tell you what model of bike it came frame. Have a look at these threads linked below, and then the parts catalogue. The "-00 or -60" etc numbers at the end mean that it supercedes an earlier part. -00 being original, -10 supercedes that, and -20 would supercede both earlier ones.

    http://2fiftycc.com/index.php?threads/fzr250-3ln-document-part-numbers.7768/

    http://2fiftycc.com/index.php?threa...0-3ln-bodywork-frame-engine-carburetors.3469/

    The 3LN ignition boxes are all more or less the same. I don't think that the ignition timing is changed across the 3LN1-3LN5. I know that the 3LN6-7 ones will start cutting spark at 16,500 RPM compared to 18,500 RPM of the 3LN1-3LN5, with the EXUP valve coming fully open at 10,000 RPM. The ignition timing is on a fixed curve based on engine RPM.

    [​IMG]
     
  10. gregt

    gregt Well-Known Member Premium Member

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    Given how far from stock this engine is, I don't really need to know which model it came from...Not a lot is relevant.
    But I hope I can assume that both the boxes are mid - period 3LN1 - 5 as to my knowledge very few of the later 3LN6-7 ever came to NZ. I'll mention again, the boxes were bought separately from the motors - from a different source.
    When I can finally get some manuals - and supplements - downloaded I should be able to mock up an ignition circuit and try for a spark...
     
  11. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Looks like you have premium membership so you should be able to download

    EDIT: Scratch this link, looking for the doc that has parts list for all models...
     
    Last edited: Aug 15, 2016
  12. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    This is what I was looking for.

    [​IMG]

    -00 is for original 3LN1. -50 is for 3LN3/5. -60 is for 3LN6/7 with reduced redline RPM.

    I ran a 3LN7 engine with a 3LN3/5 box for some time with no issues. Wouldn't recommend it as the 3LN6/7 have different cams and don't like revving over 16,500. I got a -60 box with the yellow sticker on it from a wrecker in NZ actually.
     
  13. ruckusman

    ruckusman Well-Known Member Premium Member Dirty Wheel Club

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    personally I'm loving the re-sleeve mod, different pistons with the appropriate deck height to not need a spacer...300 -350 CC+ Fzr perhaps
    steel or aluminium liners BTW?

    Amazing work all up
     
  14. gregt

    gregt Well-Known Member Premium Member

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    Cast iron liners - machined from solid as spun cast tube ain't available this small diameter. Good luck finding pistons with the right gudgeon pin - and the same deck height. Most of the later 400's went to bigger pins.




    OKay...so I have one 3LN3/5 box with the high rev limiter and one late one with the low cutout. Don't you already know which will prove to be U/S...Ah well, they were cheap. Thank you very hard for the info. Before youi deleted the link I downloaded the page with a wiring diagram anyway.
     
  15. husaberg

    husaberg Member

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    Greg I have added all the stuff I can scrounge up onto a flash drive and will be sending it to you.
     
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  16. gregt

    gregt Well-Known Member Premium Member

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    Right - after a road trip I now have...
    Two late frames and swingarms - with one good shock and one rear subframe which has been cut about.
    One set of forks - with a 4 pot caliper grafted into position to use a 320mm disc...
    Five rims in total - 2 fronts and 3 rears. i set slicks fitted, one set wets, odd road tyre on the 5th rim...
    Two std tanks - one mint, one, so-so..
    A fiberglass seat - generic yamaha FZR/TZR
    Enough to go on with.
    To do...
    Make subframe from sheet alloy to mount the seat i have - as late type Tigcraft.
    Go over all frame bits and recon where needed, tidy where needed.
    Make an in-frame tank similar to early FZR400, sheet alloy again.Plus knock up a mould for a cover...
    Think light...

    Also it would appear that if I can find an early non - exup ignition box my life would be easier....

    Still contemplating carbs.
     
  17. ruckusman

    ruckusman Well-Known Member Premium Member Dirty Wheel Club

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    @gregt Do you have a target carb bore diameter you'd like? Prefer CV over flatslides or vice versa.

    I came across some good reading recently which stated that the final CV carbs used on the SRAD GSXR's were the best developed and working CV carbs with comparable performance to full EFI.
    GSXR600 SRAD carbs might be suitable
    Happy to do some internet research for you to give you a list of suitable candidates if you have some initial parameters
     
  18. gregt

    gregt Well-Known Member Premium Member

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    I really do NOT want to use CV's. Generally there are no alternative needles available which makes setting up on orphan motors bleedin difficult...Also they are physically bulky and the ports are quite close together.
    I have a pair of Mikuni TM28's which I could quite easily convert to Dellorto jet layout which would let them go to around 40 degreee downdraft. These on slightly curved manifolds are the fallback position. Target bore 28 - 30mm non CV.
    The local Vintage club swap meet is coming up and i will scour the site for any small twin choke downdraft Webers or Dellortos of course. Even small single choke downdrafts X 2 are possible.
    In an ideal world I'd have the budget for a pair of FCR's...
    A guy here has found an alibaba company making (or at least listing...) copies of the Yoshimura downdraft carbs - minimum order 50 units....You'd think someone in China would be doing FCR knockoffs but we can't find any.
     
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  19. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    You can get the Yoshimura YD MJN28's for around $120 plus post from Thailand
    What about the OKO PWK flatslides, they are pretty cheap.
    Would need to adapt a 90° manifold though
     
  20. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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