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Project FZR 250 overbore -> 300+

Discussion in 'Your 250cc Projects' started by ruckusman, Nov 14, 2018.

  1. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Assuming this page is correct, IN - 22mm EX - 19mm - stem diameter 4.5mm

    48m -> 54mm - 26% increase - @maelstrom reckoned the valves won't be a limiting factor in the volumetric efficiency and I ten to agree given that @Mngforce did a lot of their RVF/VFR400 engine development with the standard valve train

    Most of my late night searching was just me keeping myself amused - late night TV sucks
     
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  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    It probably isn't - just thought it worth mentioning in passing, I thought it would be good to at least have something in store for later development
     
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  3. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    On the topic of valves - this is some impressive work to keep his Gogo mobile going - this is one guy that's just can do - reminds me of Murdo in some ways

     
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  4. Murdo

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

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    Wouldn't mind his equipment, particularly the tool post grinder.
    Are FZR valves that hard to get that he had to 'bodgie' that one up with the welder? Wonder what material the filler rod was? And what about the heat treatment after welding?
     
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  5. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    In the title he says Stellite tig - I've checked and there are several types of stellite tig rods available.

    I think he makes it look easy

    Unfortunately there are many negative comments, although there are some which appreciate the calibre of his work, he's obviously done the same work previously

    I didn't think much of his lapping technique but that's just my opinion, and I'm not about to shove that at him.

    This bike is manic


    This is an interesting video of annealing



    This thread is also interesting on valve & pushrod annealing and hardening - they make it sound so simple - but they've obviously got serious skills and experience
    http://listerengine.com/smf/index.php?topic=914.0
     
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  6. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Valves 'n stuff:
    Yes, don't worry about the head. This is a common mistake that people make. Enabling the head to flow more will allow the peak torque rpm value, and horsepower, to increase. It will do nothing below the rpm range that I mentioned before because the standard head already does a good job of filling that. I would ignore it completely.
     
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  7. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    This is an interesting read on ports - specifically Yamaha cylinder head ports, and on bikes of the same era also

    https://operationmoto.wordpress.com/2015/01/09/the-o1-and-only/
     
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  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK reviving an old thread because I now have a workspace and some cash to progress this project.

    One thing which kept me reading late at night was the material for the cylinder sleeves - recent developments (relatively) in pure uncoated aluminium sleeves - called Diasil by Yamaha made me ponder the possibility of perhaps taking advantage of both the better thermal characteristics of aluminium sleeves & block combination and a friction reduction due to the super hard silicon which is left after the chemical etch of a Diasil (also called Alusil by another trademark) sleeve.

    I'm investigating basically taking the central sleeve portion of either a Yzf r125 cylinder (52mm bore) or a Yamaha T135 cylinder (54mm bore) - water jet cut from the cylinder assembly, them machined down to make a sleeve to be fitted.

    Reason that I am investigating this route is because I cannot find someone that supplies Alusil cylinder sleeves in the required bore diameter. - They do exist, Mahle/MSI service makes them to recondition/repair aluminium blocks, just in larger diameter bores for passenger vehicles, so I'm not out of bounds on what can be achieved
    http://www.pierburg-service.de/ximages/ks_si_1199_en_web.pdf

    This document is a treasure - so much good information - it's too large to upload to the site
    https://www.electrosil.com.au/pdf/KS.pdf

    If anyone comes across a Yzf r125 or a WR125 cylinder for sale in Oz during their travels through the net, please give me a holler
     
  9. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    OMG that has to be the current "Bible of Cylinders", great work ruckus.
     
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  10. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I've just read through the majority of it, it's stunning well written given that it basically makes very technical information easily understandable and digestible - whoever wrote it really knows their stuff and how to communicate it very very effectively
     
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  11. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Researching bearing colours and attempting to see what sizes they correlate to I came across this

    First the part number(s) for each of the bearings on this site

    http://www.firstclassmotorcycles.co...998/fzx25-zeal/crankshaft-piston#n_3LN1141600

    1HX-11656-00 - Blue
    1HX-11656-10 - Black
    1HX-11656-20 - Brown
    1HX-11656-30 - Green

    This page has the relevant measurements of each of the four colours, now the last two digits do correspond to a size difference in thousandths of a millimetre, i.e. 10 is 1 hundreth of a millimetre larger - I thought that may be the case however didn't want to make any assumptions.

    EDITING the above as I don't want incorrect information in here - I measured a crankshaft yesterday and got 0.005mm between numbers, yes that's 5/1000ths of a millimetre.

    However I am yet to measure bearing shell thicknesses to get meaningful numbers, but I think the shell material thickness varies by ~5/1000ths of a millimetre which concurs with measurements which @maelstrom made.

    http://yamahafzr250.blogspot.com/2013/12/yamaha-fzr250-2-kr-1987-88-1.html

    Interesting translation(s) but good information

    Yamaha FZR 250 2KR 1987-88
    A selection of inserts

    PART 1. Selection rod bearings empirically
    There are four sizes of main bearing rod (Measured - micrometer)
    cervix Insertion
    1. 27.00 mm -> 1HX-11656-00-00 - Blue
    2. 27.01 mm -> 1HX-11656-10-00 - Black
    3. 27.02 mm -> 1HX-11656-20-00 - Brown
    4. 27.03 mm -> 1HX-11656-30-00 - Green

    Now at least when I strip down the crank and rods and compare the measurements stamped on the engine case and crank I will be able to discern what the original sizes were and take measurements to determine if they have changed substantially due to wear

    These tolerances are obviously minutely measured because of the clearance ranges involved

    @maelstrom has posted the FZR400 explanations of the sizing process and the maths involved to arrive at the correct colour selection, I just cannot find the post right now
     
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    Last edited: Nov 17, 2021
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    This is post with the FZR400 service manual information by @maelstrom

    Once I begin to take actual measurements - I should be able to make sense of all of this and give actual size numbers to the sizes stamped on both the cases and the crank web

    https://www.2fiftycc.com/index.php?...ne-behind-block-head.10478/page-9#post-124369

    Here from the FZR400 1WG. If you look at the 250 manual you can see similar. Obviously the 250 manual needs to be translated. On this rod the 'E' means nothing. Probably like the 'C' on yours.

    [​IMG]
    [​IMG]
    [​IMG]
     
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    Last edited: Jul 7, 2019

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