v twin JAP

  1. zeppelin builder

    zeppelin builder Member

    Messages:
    1,407
    Location:
    peoples republic of scotland
    IMG-20200421-WA0002.jpg 20200519_201250.jpg 20200521_102457.jpg 20200521_131123.jpg 20200520_163025.jpg 20200519_120940.jpg IMG-20200521-WA0005.jpeg 20200520_173340.jpg 20200521_191810.jpg got roped in to get a 1921 williamson going for a friend it had been thrown together to sell in one big lump it looked nice but has been a total pia for starters the rebuit motors was very hard to turn over so i ripped it apart .
    crank shaft had 35 thou run out luckily it was at 90 deg to the big end so a few hefty skelps aith a big thor hamer got that to 2 thou and spun freely it has a,2 lobe cam that works the spindly rockers it took ages to figure out what went where
    the timing marks were miles out so i ma naged to dial in a sporty setting ring gaps on the bone china cast iron pistons were checked and with liberal coatings of moly paste were bolted up
    it had a big b+b brass sport carb that fouled the frame ,i machined the manifold down on the dsg very slowly with hand hovering above the emg stop button
    trial fitted it and set about making the cable guides silver soldered to the lid
    next all the chewed hex bits were turned down and a new hex ss on
    the peculiar mount bolts with square hex were tigged up anx a new square was forged on while still hot
    nex job cut and extend float bowl stem and add 30mm in length i did this wit ac tig it was a horrible job with heaps of white zinc smoke and totaly trashed the gas lens and ceramic ,this was shaped with carbide burr anothr horrible job drilled through and the float bowl re attached by silver soldering , spent ages tonight sorting out fuel pipe fittings they were totaly useless auto jumble junk
    turned down a rogue valve cap earlier it was riding on the other ,so many little faults keep appearing ,lesser mortals would given up by now , will possibly start it tommorow thats what i get a kick from , be an exiting ride 60 plus mph and very rudimentary brakes 5 inch rear drum and bicycle stirrup front might take the paint off the rim if yer lucky
     
    Bluemotion, ronan, Gwil and 16 others like this.
  2. Matchless

    Matchless Member

    Messages:
    714
    Location:
    Essex UK
    did he buy it at auction? all fur coat and no nickers! my Matchless car was restored 20 years ago for museum display...…… will get it going this year, maybe,

    if you know anyone with CS gears I have a box with one gear missing, maybe the small KS gear with the square hole, must check, I would swop the box for something I needed.
     
    stuvy likes this.
  3. zeppelin builder

    zeppelin builder Member

    Messages:
    1,407
    Location:
    peoples republic of scotland
    il ask around ,re gears ,i believe an old coffindodger was doing it up and he croaked ig thsn,somsbody assembled it in big lumps to sell , i reckon ilbs another week on it i suspect the back wheel is liightweight bsa with the dual brake it looks very flimsy for a big side car hauler
     
    stuvy likes this.
  4. Matchless

    Matchless Member

    Messages:
    714
    Location:
    Essex UK
    Matchless also used a dual rear brake on the mid 20's 250cc model R, I am building a pile of bits that may one day become one, strangely they used the wide rear drum on all the models even with just one set of shoes inside,
     
    stuvy and tom2207 like this.
  5. tom2207 Member

    Messages:
    474
    Location:
    uk northern ireland
    all i think about when i see a big twin jap engine , is ,, Brough ,, oh for a superior . my dreamss are the same shape as that iconic twin tank ,,,
     
  6. tom2207 Member

    Messages:
    474
    Location:
    uk northern ireland
    [​IMG]

    George Brough and TE Lawrence , any excuse to post a pic ,,lol
     
    zx9 and Hopefuldave like this.
  7. zeppelin builder

    zeppelin builder Member

    Messages:
    1,407
    Location:
    peoples republic of scotland
     
    tom2207 likes this.
  8. tom2207 Member

    Messages:
    474
    Location:
    uk northern ireland
    But it wasnt Superior ........... !!
     
  9. frank horton

    frank horton V twins are great but 4"s rule.........

    Messages:
    1,680
    Location:
    Soon 2 B Crete
    be nice to have a garage with toy's like that.......
    well done u for the effort.......I know the pain.........
     
    Ali likes this.
  10. dobbslc

    dobbslc Forum Supporter

    Messages:
    4,978
    Location:
    Hertfordshire UK
    Great write up!
    "a few hefty skelps" :clapping: made me laugh that one!
    I was looking at that valve gear wondering what it was for a while then the penny dropped! Wonderful stuff.
     
    stuvy likes this.
  11. mike os

    mike os just a little insane.....

    Messages:
    6,025
    Location:
    North Wales
    beautiful bikes
     
  12. Greeves246 Member

    Messages:
    174
    Location:
    Cheshire uk
    I take it that's the Norcati hiding at the back?
     
  13. Who finds a new 1930's JAP engine on Ebay. Goes by the name of Lucky B.
     
    stuvy, tom2207 and Westfield-builder like this.
  14. slim_boy_fat

    slim_boy_fat Forum Supporter

    Intriguing....a pic would be good, never heard of them. Is it some kind of 'Special' ?
     
  15. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Messages:
    14,785
    Location:
    East Yorkshire
    There’s a bike builder I know called Sandy, [he’s been in BHS many times] he built a AJS in the same vein. He put it into to bike show I was asked to adjudicate on. One of the other guys would not have it that had been built the year before.
     
    Matchless and Alan Reynolds like this.
  16. stuvy

    stuvy Member

    Beautiful bike Iv Always wanted one
     
  17. tom2207 Member

    Messages:
    474
    Location:
    uk northern ireland
    Its that key banging thing again ,,, very few new ideas in this world . bet they all wore their flat caps backwards then too. Bitchin..

    The guy who built it is just such a character , really tidy bike.
     
  18. stuvy

    stuvy Member

    Alan Reynolds likes this.
  19. Cobbler

    Cobbler Codger bodger

    Messages:
    4,776
    Location:
    Gloucestershire UK
    When I was younger & dinosaurs roamed the earth, someone nearby rode speedway, his bike had a big JAP engine, which I think ran on dope. He used to test it with a blast down the road, the sound & smell of that on full chat was terrific.
     
    zx9, ronan, tom2207 and 5 others like this.
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