SF won't fire on both cylinders for long

[mik667]

hey all
Well i have assembled the SF, and for about 15 minutes it ran sweet - best acceleration I've felt in it - yeah! then it went on only 1 cylinder, figured it fouled a plug, new plug and it ran for about 1 minute and then quit on that cylinder again! shit! then again, and again w/ different type plugs etc - some times only 20 seconds or so before the same cylinder quit... i can pull the plug from dead side and place in the other side and it fires right up on that cylinder(!) - yikes

Checked the compression 180 lbs both sides (!) - I've tried changing the coils (w/ new ones) - same results, new spark plug wires & doubled checked the floats - (same results) - ran squiter fluid through ever orifice on the carb and it still does it - finally i am suspecting the Sachese EI  - i have noticed that it if i go to short out the sparkplug cap/terminal on the offending side (i have some old school hot rod spark plug caps on it temporarily  to help me figure the problem out that have the tip of the sparkplug exposed - they clip on the sides of the plug its-self) there is no/weak spark that will arc between a screw driver placed on the sparkplug  and  the barrel making me suspect the spark on that side is running only part time - on the opposite side (thats running nicely) when i do this a big arc  goes between the screwdriver and the barrel and the bike dies.  I've rechecked all the connections, removed them and replaced them in the control box etc w/ no cure.

I have noticed if i set the sachese to just "fire both plugs" by dialing "0" i get a big arc w/ screw driver on both plugs (and nice spark if plugs pulled out )

anyone had a failure like this - or other suggestions to look at? driving me friggen crazy

thx as always! Mike

 

[Paul Marx]

Have you still got the points and mechanical advance, try again with those in place and set up.
Paul

 

[Tippie]

I don?t know the Sachse, but if it has two triggers you could try swapping their inputs to the controller, and then swap the wires to the coils / the plug leads to the sparkplugs. This should help isolate if it is trigger, controller, coil etc. That it fires both plugs in the test mode tends to steer you to a trigger or controller. Wires to triggers can cause intermittent faults as they do get heated and cooled many times, and all wire connections must be good (as you have checked).
If it is the controller for sure apparently an Ignitech can replace it if Sachse (RIP) company is no longer trading.
I have had my say on points, Paul

 

[phil37]

  Just had a very similar problem with a Sasche on a Montjuic - Regards - Phil

 

[mik667]

thx guys, messed with it again, including removing the trigger and making sure the rotor/sensor didn't have debris on it (none) and tippie's good suggestion of swapping the inputs wires to the controller and reversing  the coil/sparkplug wires - she still wouldn't fire for any length of time on the same side  aftyer the switch making me think the controller has taken some kind of dump despite its ability to fire off both plugs in the test mode - crap - bet it doesn't even have 3 hrs on it.....

 

[Laverda SF]

Polish the points with 600 Wet Grit wrapped on a finger nail file or Feeler Guage.
Set Points at .018"- Make sure he cavity chamber is dry.

Heed the following:

POINTS;  .4 - .5mm or .018?  Modified PN: GB-4173PT True Tech 72 VW Super Beetle
                 NOTE: Knock out Trigger Pin and drill with 5/16? Bit.
                              File 1/16? x ?? tab of top for Right Set of Points.

TIMING: ENSURE Points are Adjusted @ .018? First
                The Right/Back Plate Points control the Right Cylinder.
                The Left/Cam Floater Points control the Left Cylinder.
                Use Light Bulb Tool on Right Point Set
                North American Pump Gas 93 or 94 Octane is Essential (98 RON ? EURO)

                                                         RIGHT Side Points
                Using Socket on Starter Clutch Nut
                Rotate Engine Clockwise. Blub should light when PM is at TDC Mark on
                Engine Casing. If Bulb Lights Before -  Timing is ADVANCED
                                         If  Bulb lights  After   -   Timing is RETARDED

                Rotating Breaker Plate  - Clockwise          =   Retards    Timing
                                                      - Anti Clockwise   =  Advances Timing
                Similarly for Left Floater Points Clockwise Retards & Anti-Clock Advances
                The tighter the Points the more Advanced you get.

                                                         LEFT Side Points
                Repeat procedure with Light Bulb Connected to Left Point Springs
                Adjust by loosing the 2 Screws that which hold the Left Floater Plate.
                Using the smaller eccentric screw. Seems the Left Floater Points must
                be set at FULL ClockWise (Retarded Position) to  maintain a .018? Gap
                for Both Sets of Points when timing is set to Specs.

                USING TIMING LIGHT (Preferred method as it takes slack into account)
                When the Back Plate and Adjustable Plate are in sync. You should be able to
                set timing for both Cylinders by moving the Back Plate.

                Always check Point Gap is set at .018? after adjust timing.
               
   NOTE: Flywheel mark approx 40 Degrees ATDC to adjust Points.
                Ensure the Mark on the rotor is pointing at the Points to be adjusted.

PLUGS:  NGK B8E S ? Gap at .7mm or .028?

CARBS :  Dellorto VHB 30 A(S) << IMPORTANT >> Ensure there are NO AIR Leaks.
                 Using a HEX Screw Driver Item, Set Throttle Stop and Turn Back 1 Turn
                 Idle Air Screws 1/2 Turn Off Seat.  Manual Recommends 1.5  to +/-.1/4 turns
                 Main Jet 125 Orig (130 Now) ? K2 Needle Position 2nd Notch ? Idle 800rp
                 OK that's with 2 into 1 Headers but general timing is no different irregardless of the pipes or Jets..

Just play with it an you will eventually KNOW What to Do.

To keep dampness outta the point enclosement, I use a bead of Permatex ANAEROBIC Gasket Maker on the Main Casing / Distributor Cap and drill a 1/8" hole in the bottom of the Cap to drain water vapor.

 

[rowdypat]

.......except, he's not running points ignition!
Could it be as simple as a dud (or shorting) HT lead to the offending side.