Bultaco Metralla advice needed

Discussion in '2 smokers' started by vtduc, May 10, 2009.

  1. vtduc

    vtduc Been here awhile

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    A friend of mine brought over a Bultaco Metralla he came by a few years back. Supposedly it was rebuilt after he purchased it. He stated that he could start and ride it a mile or two before it would quit. If he let it sit for a while, he could re-start it and repeat the same mile or two befor it quit. It sat in my garage over the winter and we tried to start it yesterday. Fresh gas and pre-mix, clean plug. Its getting gas and spark, but will only fire briefly, and dies as soon as throttle is opened. If I pull the plug after it dies, its wet w/ gas. Supposedly my friend saw it run up and down the road after the rebuild, but I don't think he actually rode it any distance.

    The bike has an old single pull Amal Concentric carb, and the only thing I can think of is that the float height is way off. I've found some info on that type of carb, but I haven't tried to pull anything apart yet.

    Any advice from the collective?

    Thanks in advance
    #1
  2. RecycledRS

    RecycledRS Along for the ride

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    Back in the day I can remember several Bultacos had problems with the ignition system failing in just a fashion as you describe. May not be your problem but try pulling the plug and checking for spark when it dies again. Bill.
    #2
  3. Donzzilla

    Donzzilla Been here awhile

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    There is a few things that could be wrong with it.

    1. They were wired so that when the tail light went out, you would depress the rear brake lever and it would shut the bike off. It 's weird, but will drive you crazy if you don't know it. It was supposed to be a safety thing, so you wouldn't ride in the dark without a tail light. Try a tail light bulb first.

    2. There is a little pen spring and ball in the handel bar mounted head light switch. Sometimes the little ball pops out and will roll around and make contact with the kill button. Then it will then move away let the bike start then not do it again 'till whenever.

    3. The coil mounted under the gas tank could be bad. Sometimes when they warm up they quit.

    4. Bultaco's had some crappy wiring to start out with. Believe me it didn't get better with age. Them little bakeolite connectors that held them together were no real prizes either. Check to see if something's loose in them.

    5. Last but not least. The stator could be bad. I would save that for last, as it is not usually the problem and it is the most expensive part.

    Parts can usually be found on e bay or go directly to Hugh's Bultaco in NY www.bultaco.com 518 851 7184.

    When they run they are great little bikes. Feel free to PM me if you have any other problems with your Bultaco's.

    Zilla!

    <a href="http://www.flickr.com/photos/donzzilla/3292889488/" title="Jaki-metralla by donzzilla, on Flickr"><img src="http://farm4.static.flickr.com/3654/3292889488_843d533f9a_o.jpg" width="600" height="830" alt="Jaki-metralla" /></a>
    #3
  4. vtduc

    vtduc Been here awhile

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    Thanks guys! We'll check for those electrical gremlins.
    #4
  5. Sniper X

    Sniper X De Oppresso Liber

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    put a Boyer Brandson ignition in it and youll never have another problem, or should I say No Mas Problemos de Electronicos.
    #5
  6. Donzzilla

    Donzzilla Been here awhile

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    That would be nice if they made one for the Bultaco:1drinkI have also had my share of the BB ignitions fail also.
    #6
  7. crampfan

    crampfan Banned

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    I had a mud dauber build a nest in the exhaust of a old hodaka I had, I kicked on it for days, all it would do was foul the plug.
    #7
  8. norton73

    norton73 drinkin'

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    check the condenser. Not sure on Metrallas, but most of the sherpa Ts had the condenser mounted behind the flywheel where the heat from the engine could cause the crappy thing to fail.
    On my bikes, I rewire so the condenser is up under the gas tank, next to the coil where things are a little cooler.
    #8
  9. vtduc

    vtduc Been here awhile

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    Thanks again for the replies!!! The burning question in my mind is: We can kick the bike over w/ the plug removed, and it shows consistent (albeit weak....when kicking (low revs)) spark, But when the bike is kicked over w/ a clean plug inserted and the carb tickled, it goes RING RING Ring Ring ring ring ring ring ring ring ring, and then dies. The headlight lights up bright when its running for those few seconds (glows when kicked over) but I haven't looked at the tail light yet during the process. We just can't keep it going once it catches, either bogging or starving when the throttle is applied. That keeps me thinking its a gas issue, but I've never been particularly good w/ 2 strokes (I traded an RD400 for 3 cords of firewood about 20 years ago, because I couldn't get the Zen of getting it tuned properly...............
    #9
  10. channelcat

    channelcat Been here awhile

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    Zilla rocks...
    TH
    bmwthrottlesprings.com
    #10
  11. Strong Bad

    Strong Bad World's Foremost Authority

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    Sound like a fuel flow problem to me. Check to see that the petcock flows well, and then check flow through the float needle.
    #11
  12. darmst6829

    darmst6829 Been here awhile

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    Change the condenser and measure fuel flow at the petcock. Leave the old condenser on the stator plate and run a wire up under the gas tank to the new condenser. Lawn mower condensers work fine. The FEMSA ignition system is solid, I have logged thousands of miles with out problems.
    Make sure end vent the ignition cover, I would drill one in the bottom of the cover.

    Dave
    #12
  13. Nitro_Fluffy

    Nitro_Fluffy Been here awhile

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    You might wanna pull the head(s) and see if it's been seizing. I'm assuming this is a two stroke, and you're using premix?
    #13
  14. ducsingle

    ducsingle Been here awhile

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    MZ-B makes an electronic ignition kit for the Metralla. Rick Yamane on the bevelheads list can get you one.
    #14
  15. jcf

    jcf Been here awhile

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    My Model 8 is having issues.
    Went through it - carbs - new plug cap - new plugs - coil checked out (and even tried it with a new one) - new condenser and points checked (and re-checked).

    Was running great though headlight was a high beam wouldn't work and the low beam was very bright.
    Tail light also out.

    Cleaned switch and headlights worked as they should.

    Checked wiring and curcuit on the tail light and and those checked out.

    Took it for a ride and still ran fine.
    Got a new tail light bulb and then the it all went to hell.

    Wouldn't start.
    Put old bulb back in - still wouldn't start.
    No spark - kept fiddling - tried new coil. Still no spark - put old one back on ( since there was really nothing wrong with it )
    Checked points again.
    No spark - no spark - no spark - THEN a beautiful healthy spark for a few kicks - THEN no spark........

    Could there be a short ?
    If so where should I be looking ? - Tail light curcuit ? - Magneto ?

    Thanks for any help.
    #15
  16. Donzzilla

    Donzzilla Been here awhile

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    That pesky white resistor under the seat could be a culprit or it is the tail light circuit. For whatever reason, they made them bike to not run if the tail light didn't work. They say it was a safety feature. Try riding one that stalls out every time you push on the rear brake. That's real safe. Check all of the tail light connections. Them little black screw together connectors tend to corrode and make a bad connection on the old crusty wires. I have had good luck with taking them all out and snipping just enough off of the wire, stripping off the sheathing to expose some new clean wire. You can take them connectors apart and clean inside them too. Age does not help them at all. If you have the time and $$$ it's good to put new wires in them all together. They ran through the frame and over time the pressure put on the wires, tends to break them.

    If you don't have the time for replacement, try a bell test with a meter to make sure all the wires are making contact all the way through. Make sure you wiggle the wires when testing to see if there's any interuption.

    Hope this helps, Zilla!

    PS.. Glad yo said you checked the handle bar switch. I had one of them drive me crazy for months. There's a little ball with a tiny spring that makes connection on the multi location switch. It became dis-loged and would roll around in there. Every once in a while it would make contact with the kill button and shut the bike off. Move it around to start it and it would roll away, allowing it to start and run fine, until it hit again. Sometimes it wouldn't roll away and I couldn't get it to start any way. This went on for a while before I found it.
    #16
  17. jcf

    jcf Been here awhile

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    Thanks Zilla - I checked that switch because you had mentioned it earlier in this thread.

    Do you know if the wiring diagram was the same for the Model 8 as it was for the Model 23 ? The M8 was 6 volts and the M 23 12 volts .
    I can't find a manual for the 8 anywhere and that is the one I need.

    That issue with the tail light ?
    Was that the same as well with the earlier 200 cc Metralla ?
    Because my bike was running, and pretty well when the tail light had the old dead bulb in - it was when I put in the new bulb it stopped sparking.
    I put back the old ( dead ) bulb that was in when it was running and it still wouldn't run.

    Because the headlights were bright and the spark strong - when it was firing and even the few times it came to life after it stopped running - would that lead you to discount that the stator is bad or should I have that tested ?
    #17
  18. PSchrauber

    PSchrauber Long timer

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    You may check the points too, it's very "commen" that they fail too, Check if the surfaces are still aligned to each other, if not grind the parallel using a point file, check the distance which should be 0,4mm.

    Ignition point, her I know only the timing for Sherpas which is around 2,5 - 2,7 mm befor OT.

    To get rid of any issues from other electric wires or components that are mount, you can
    only wire up the main ignition, at least the coils of the Sherpa have an extra eartch connection,
    without the spark is weak.

    Connection generator to ignition:
    [​IMG]

    The bike may have a carb issue too, I would check the floater and if it work proper, expecially the
    floater valve.

    Last, I discovered that at least the Bultaco Sherpas like the older multi heat range plugs much more then any single range or modern plug, (classic plug's are available through http://www.gsparkplug.com/shop/)
    #18
  19. jcf

    jcf Been here awhile

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    Thanks P ;

    That is a very interesting link for the plugs.

    I am pretty sure the points are good ( checked and re-checked ) and I went over the carb a number of times and replaced the needle.

    It was running great and the spark and lights were strong - until I tried to fix that tail light .
    I am clueless as far as electronic stuff
    #19
  20. PSchrauber

    PSchrauber Long timer

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    When it is not an ignition / crab issue and the bike runs without rear light / brake light and you have now installed the brake light assembly? Then - as already mentioned - you need a resistor for the rear and brake light, if not all energy goes to the rear brake light setup. The not very tiny archaic thingy looks like this:

    [​IMG]

    Connection / where to place and to connect:
    [​IMG]

    See # 08 (Widerstand).
    #20