Reviving a Bultaco

Discussion in '2 smokers' started by bmwblake, Dec 4, 2011.

  1. PSchrauber

    PSchrauber Been here awhile

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    That is the stock shifter (long version), there was too a short version available, last but not least there is also a version short with foldable pin still availalble. Mmmh look up my pic stack now, if I have ...

    Here the long version, the lever on the right side,
    (additional parts are the bolts, nuts, ... after replating, rechroming,...)
    [​IMG]

    The short shaft, (in the middle):
    [​IMG]

    The gear shaft with foldbar pin, (the upper one, (lower one is Husqvarna):
    [​IMG]

    For the longer shaft you need to lift the foot for gearing up or down, with the shorter one you can still stand on the pegs, (actually I have small feet, ... :D)
    #21
  2. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    [​IMG]

    ... :D)[/QUOTE]


    Those are some seriously small tires......:lol3
    #22
  3. PSchrauber

    PSchrauber Been here awhile

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    Those are some seriously small tires......:lol3[/QUOTE]

    Sometimes my brain have ultra long wires as we say here, do you mean the rims, (18'' and 21''), or the rubber on the gear shaft?
    #23
  4. PSchrauber

    PSchrauber Been here awhile

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    What's up with the bike, ... please ... ?
    #24
  5. bmwblake

    bmwblake upside down parker

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    the bikes in the same spot it was a few months ago. i've been working on an r50/5 and haven't gotten back to the bultaco. i need to get it running to get it out of the way in the garage.

    it runs, i just need to get the gas tank and a few smaller items worked out.


    [​IMG]
    #25
  6. bmwblake

    bmwblake upside down parker

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    this bike's been lingering for a long time. certainly overdue for an update.

    there've been a few nights of this:
    [​IMG]

    new fork seals are in. it's fun to have such a light bike that you can easily roll it over the lift sideways to get the front end off the ground.

    i got ready to start the bike last week and it hung like it was at full throttle. i'm sure the neighbors hated me. the new kill switch came in handy when i found out that you can click the bike into first while kick starting if you aren't careful. nobody was harmed in this event. i wish it were on video. i'll forever be starting this bike with the front brake firmly applied.

    the biggest challenge on this bike has been the tank. i mentioned before that someone had at some point overtightened the petcock mounting bolts and stripped the threaded studs that are inserted into the bottom of the tank. it was then somewhat repaired with jb weld and various other bits of goo.

    here it is during the cleanout process:
    [​IMG]

    [​IMG]

    i had to cut out all the jbweld, then borrowed a plastic welder to repair the tank. i heated some nuts and sunk them into the tank where they needed to go. i shaved some plastic off the underside of the tank and that welded very well to cover the nuts and provide strength. i then used some new PE rod to weld more and then sanded to provide a smooth surface.
    i used some sealant around the bottom of the petcock after mounted as a final measure.

    it's not good enough. after a short round of riding on the bike the tank is leaking again where the petcock mounts. back to the drawing board.

    [​IMG]
    #26
  7. lamotovita

    lamotovita Ageing Adventurer

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    I've never heard of anyone who has succesfully repaired one of the plastic tanks. The Italian repro tanks look original and seem to work fine.
    I have the original tank on mine. It's for riding, not show. Here's a photo to keep you inspired.[​IMG]
    #27
  8. Twin-shocker

    Twin-shocker Long timer

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    Why not machine a tubular threaded fitting with you can fit through enlarged tap outlet hole from inside the tank, which with o-rings either side and secured with a nut on the outside should mean leak free fuel outlet? All you need to to then is plastic weld up the previous mounting holes completely, and fit a tap with female thread onto your new mounting.
    #28
  9. PSchrauber

    PSchrauber Been here awhile

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    Yep,
    the petcock and gastank is a real task for Bultacos, just to be sure as these little parts where often forgotten,
    do you still have the little oil seals around the fastener screws of the petcock?

    Set up shown here in the picture, (on the bottom of the right side).

    You can get an fiberglas or aluminium gas tank too, these neeed in standard outfit, M14, 1,5mm petcocks,
    (some replicas might have different connections), these old M14 petcocks with 1,5mm threads shown
    in the middle of the photo.

    [​IMG]

    The alumium tank was fitttet to model 158 and 159 if you want to look up one from E-Bay or Craiglist,
    in UK Bultacos had to have an metal tank if they had an road registration so best chance to get one
    is UK, (there where also steel gas tanks made, (much heavier!)

    Here is a 159 aluminium gas tank I got from E-Bay, still have to get rid of some dents and a paint job
    as my bike is white/blue:
    [​IMG]

    The glasfiber tank isn't bad too as you also can fit a custom paint job to the tank, (here the classic
    paint scheme for "pimped" Sherpas, (emblems not fitted as the paint was to new when the photo
    was taken):

    [​IMG]
    #29
  10. lamotovita

    lamotovita Ageing Adventurer

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    Another thing to consider.
    I believe the alloy tank requires a different seat to fit properly due to a different tank shape.
    #30
  11. PSchrauber

    PSchrauber Been here awhile

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    The slope of the aluminium tank is identical, it is some mm wider, as mentioned
    there are metal tanks also of the later models in use, expecial in UK, these fit
    perfect but are a little bit bulkier in overall design.

    [​IMG]
    #31
  12. Twin-shocker

    Twin-shocker Long timer

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    Have you a picture of the very slim GRP tanks often fitted to tricked up Bults built recently in Spain?
    #32
  13. PSchrauber

    PSchrauber Been here awhile

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    See post #30, pic at the bottom.
    #33
  14. bmwblake

    bmwblake upside down parker

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    i don't have o-rings around the bolts for the petcock. there isn't a recess in the tank for them (if there ever was one). i have several different gasket materials that i've been trying. the last one was something that didn't enjoy contact with gasoline. :D

    i've been trying to think of a way to get something inside the tank and work from there, but now that it's been plastic welded and is smooth i don't think it's a matter of the petcock not being held tightly enough i think the gasket just failed.

    i'd like to not put the $350 into a tank if it isn't required. that's a quick fix i know, but where's the fun in not trying to fix what i already have in front of me?
    #34
  15. PSchrauber

    PSchrauber Been here awhile

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    There isn't any recess in my tank body either!

    There shoukd be a rubber seal inserted around the oval shaped upper base, (sorry for my english), of the petcock, That rubber seals the petcock to the gas tank, the surface of tank should therefor be very even were the petkock is attached.

    When the base of the petcock is sealed at the "outer edge" there is no seal where the screws go through, therefor the petcock leaks if you haven't mounted oil seals.
    #35
  16. Twin-shocker

    Twin-shocker Long timer

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    Thanks...................Is that GRP tank much narrower than than the plastic ones I wonder? Also I dont suppose if you have any idea whether a Model 59 tank is the same as the one used on the Astro?
    #36
  17. PSchrauber

    PSchrauber Been here awhile

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    It's the same width, the white stripe makes the tank look narrower, the tank is btw. a litle bit wider downwards in the front, (doesn't affect steering angle).

    Astro MX (depends to which model ) is beside the vent nearly the same, the model 59 Lobito enduro have the vent attached to the tank between the gas tap and the steering steam the Astro have the vent already attached to the gas tap.
    #37
  18. Twin-shocker

    Twin-shocker Long timer

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    I asked the question about the M59 as wondering whether it would be worth making repro plastic tanks for these bikes, as I guess all the OE GRP tanks have probably rotted long ago. Dohhhhhhh.................my lack of knowledge of Bults led me to thinking a 69 Sherpa was a M59 rather than M49.............is the M49 tank the same as the ones used on things like early Pursangs, Astros etc (the breather vent seems different deffo).
    #38
  19. PSchrauber

    PSchrauber Been here awhile

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    I would say it does looks quite similar if the 49 wasn't fitted with the "kit campion". If it will fit (and the astro tank looks a little bit longer) ... well I haven't made any measurements for comparison and don't have an Astro model.
    #39
  20. bmwblake

    bmwblake upside down parker

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    so i bought a new tank and am ready to let this one go. it runs but i'm not going to have time to ride events anytime in the near future unless i can figure out how to mount a few car seats.

    it's in the flea market.
    #40