Bultaco Pusang Service Center: Ignition

Pursangs came with Femsa ignition until 1973, Starting in 1973 they came with Motoplat units.
Ignition Topics:

PVL Coil

Grounding

Femsa - no spark

Timing Specs.

Testing Motoplats

 

 
Motoplat

Timing Specs.

2.7-2.9 mm BTDC   M135 Engine by JP Morgan set at 2.92

 

PVL Coil

Which lead goes to the large terminal? (from Lynn Mobley)

Blue lead goes to narrow PVL coil terminal

Black lead goes to wide PVL coil terminal

 

Runs Erratically, no idle etc.

I just discovered a pinhole burned into the High Tension lead where high voltage was leaking. The bike was hard to start, popped, backfired. Closing the pinhole with Silicon and putting a new Spark Plug cap brought the Bul back to prime running.

No Spark

Check, clean all plugs and connections. Check to broken wires

Grounding

Poor grounds will prevent your ignition from working well. Sand the frame where the upper coil mounts, where the engine mounts touch the cases, and sand the engine cases where the stator plate mounts. You could also run your own ground wire from the coil mount down to the stator plate.

Testing Motoplat & Repair Centers

Follow this link to learn more (go)

Learn more about Motoplats (go)

Repairing Motoplat

(in German) (go)

Vance Smith (go)
Problem with Pursang 125cc (model 117)

  • Vance removes the epoxy and then rewinds your coils..
    I have had my internal rotor rewound, but on reinstalling it my bike will not run cleanly. Last weekend I thought the problem was jetting... could a rewound stator cause the bike to run erratically???
  • I changed the main jet from 250 down to 200 and still couldn't get the bike to run cleanly.
  • Next step is to pressure test the system
  • Then I will replace the internal rotor motoplat with an external rotor model to see if the bike will run cleanly.

Repairing Motoplat

(in German) (go)

Vance Smith (go)
Problem with Pursang 125cc (model 117)

  • Vance removes the epoxy and then rewinds your coils..
    I have had my internal rotor rewound, but on reinstalling it my bike will not run cleanly. Last weekend I thought the problem was jetting... could a rewound stator cause the bike to run erratically???
  • I changed the main jet from 250 down to 200 and still couldn't get the bike to run cleanly.
  • Next step is to pressure test the system
  • Then I will replace the internal rotor motoplat with an external rotor model to see if the bike will run cleanly.

 

 

Basic Motoplat Testing

http://www.yankeetwin.com/motoplat.html

Bultaco Cable Listings

http://www.terrycable.com/CABLE%20LISTINGS/bultaco_cable_listing.htm

Mobley's Bultaco

http://www.bultacoparts.com/

Bultaco ID

http://www.jeffscycles.com/CycleIdentifications/Bultaco.htm

 

 

 

Vintage Dirt Bike Guide

http://www.off-road.com/dirtbike/machines/vintageguide/

 

How Shocks Work

http://power-mods.bizhosting.com/shocks.html

Works Performance

http://www.worksperformance.com/

 

 

Vintage Bultaco Racing

http://www.mazman.com/bikes/bultaco/1-bul.htm

 

Bultaco Pursang Center

http://www.bultacopursang.com/