alpina lost spark

[bgeacook]

I've lost spark, model 85 250 alpina.  not sure if whats there is original as a brake light was added long ago.  mostly want to know how/where to test each component before buying new coil, etc.  

been running fine then just quit like out of fuel.  added fuel (knew it was low) but would not start.  cleaned the carb, etc but still nothing.  then started and ran for few seconds then dead again.  that's when I checked for spark and saw none.

the two loose black wires (heavier one from the high tension coil, other from wire harness) were connected to terminal opposite the red wire.  

1) how do I test output from magneto

2) how do I test the ht coil

[71zman]

This sounds like the grounding problem that the Alpina lighting system is known for. The stock Alpina's have the green (ground) wire from the engine grounded through the rear brake light bulb so if the bulb goes out, the engine stops (the engine looses it's ground).

To get it running make sure the black wire from the engine is connected to the black wire on the coil and connect the green wire from the engine to the coil ground (i.e. the bolt that holds the coil to the frame) and see if you get spark.

 

bret

[pschrauber]

I assume in your first post that the bike did run before and then stopped running at once.

 

Thus I would in your situation forst get rid of the issue and then change and optimize our electrical system, otherwise there is some risk it will take much time before the bike will run again.

I would first look at your ignition system and here to the points and to the condenser. The points might have got a wrong adjustment or got burned by a malfunctioning condenser. These are the ost common issues beside a non working plug cap or an issue with the cable connection between coil and cable to the plug or cable to thr plug to plug cap.If here everything is sorted I would look up the remaining electric.

 

To the remaining electric these parts are feed by a separate cable and there should be a crude looking restrictor between the rear stop light ans the main circuit these restrictors do fail too you might check it.

To the original harness set up this should be inside all workshop manuals for Sherpas and Alpinas.

 

 

 

 

 

 

 

[stevem75]

I'd start simple and replace the spark plug. If all of a sudden it stopped.  Try a new plug. 

 

Steve

[b40rt]

White wire disconnected, looks like an earth ?

[bgeacook]

yes, the white wire (w/ ring terminal) is ground, or earth.  it was attached to the ht coil mounting bolt.  based on comments about the tail light bulb (ground going through it), I assume that this wire is not original.  

Edited August 6, 2017 by bgeacook

[71zman]

23 minutes ago, bgeacook said:

yes, the white wire (w/ ring terminal) is ground, or earth.  it was attached to the ht coil mounting bolt.  based on comments about the tail light bulb (ground going through it), I assume that this wire is not original.  

Connect the white wire lug back to the coil bolt and connect the green wire to it. Try it and see if you have a spark. If no spark - it looks like the red wire is probably connected to the kill switch (seems to be hooked to the black wire from the engine to the coil) - unhook the red wire leaving the black wires connected and try it again - I once had the kill switch malfunction that gave me the same problem. If these don't work, next would be as pointed out above, plug, points, coil.

bret

[twinnshock]

Have you tried looking where you last had it?

  I'll get my coat...............................

Stuart

[twinnshock]

During my 40 years of continuous ownership of various Bultaco bikes, the only ignition issues I have ever had is either plug or condensor.

I have a vintage car and after also after  suffering condensor issues have now fitted a modern easycap condensor from Bright spark magnetos. No issues since fitting and it does seem to have improve starting. For information my car (BSA SCOUT) is coil ignition not magneto.

http://www.brightsparkmagnetos.com/easycap/index.htm

Not yet tried one on a Bultaco but if I get any issues in the future I plan to give one of these a try. Any body else come across these?

I have no conection with this company.

Stuart

 

Edited August 8, 2017 by twinnshock

[bgeacook]

so I got it running again.  "start with the basics", they always say.  I re-attached the black wires at the terminal block- one from the ht coil and the other from..?  anyway, I cut the insulation back a little and made sure I got them both in the terminal all the way, etc.  ultimately I think what fixed it was the spark plug terminal, though.  the boot is disintegrated and WAS taped but that had failed.  I taped it good and tight and ta-da! spark!  

I'll be ordering a new terminal (along with a couple other, unrelated, items).  

thanks for the input- I learned some new stuff about these bikes, and that's always a good thing.