Setting Boyer ignition on SF2

[Lyndoneil]

I'm struggling to get my head round this, but as I understand it, I find TDC on the right cylinder as shown in pic 1, obviously on the correct part of the 4 stroke cycle, then turn the engine back to 35 degrees in this case as in pic 2.
With the engine set so, on the stator plate side I turn the plate until it lines up with the dot on the magnet viewed through the hole in the plate as in pic 3.
Well in this position it won't start and all I get are a couple of back fires and a protesting Sprag clutch.
Yet in picture 4 it shows the position in which the ignition was set and the engine will run, (badly)I can't even begin to understand how that can be.
What am I doing wrong? Does anyone have experience of these Boyer setups.
I will check again that I m turning the pick up plate in the right direction, but as it's a wasted spark system with 2 pick-up, but only a single wire from the Boyer box to the duel outlet coil, I can't fathom what difference they might make.

 

[The Sock]

I'm struggling to get my head round this, but as I understand it, I find TDC on the right cylinder as shown in pic 1, obviously on the correct part of the 4 stroke cycle, then turn the engine back to 35 degrees in this case as in pic 2.

Never turn an engine back, always forward, is the way I was taught. Eliminates backlash from the system.

 

[Rob]

How / what sets the position of the magnetic rotor under the trigger plate?

 

[rez]

For me, it seems , your Freewheel is Not Setup right. Through Out a Sparkplug and use a screwdriver
Turn the crank Till top tdc. Check, If real tdc is in Line with the Line on the Freewheel.
Good Luck.
Rainer

 

[rez]

Or is your Box 180deg?
You need 360deg.

 

[Lyndoneil]

How / what sets the position of the magnetic rotor under the trigger plate?

Hi Rob
I admit I haven't removed the Rotor to find out as at this point it's the only part that's constant and I haven't meddle with, but as the stator / pick up plate is turned and set to the mark on rotor magnet , will it make any difference where the Rotor it set to?

 

[Lyndoneil]

Or is your Box 180deg?
You need 360deg.

Hi Rez
I did use a tool down the plug hole to find TDC, as it turns out the freewheel mark is pretty accurate, the Boyer ignition is the same as used on British twins so presumably 360. The information that Boyer emailed when I asked for setup details, was for a 360 Triumph, as they dont have any for Laverdas.
God knows!

 

[Rob]

I know nowt about the BB system and yes, you may be right about the rotor position not being an issue provided that you can see the timing mark through the trigger plate hole as you show in your photo. BUT a YouTube video I watched refers to two holes - one for clockwise and the other for anti clockwise timing. Does yours have this? If so, which hole are you using?

 

[1200 JOTA]

maybe not helpfull .. but I've found that Boyer set-up instructions can be wrong (simply) and it's best to eye-ball the position of the rotor vs pickup @ TDC

just confirm engine 'close to TDC' and then fiddle stator and rotor to be approximately 'set to fire' around 10 degrees before TDC

the postion of the stator might be out as well as the rotor ... change either to get a 'will fire' at TDC and then refine the position of the stator via the slots with a strobe

one (stator or plate) or both could be out of place but use very simple logic to sort them .. all you're looking for is a spark on compression ~ 10 before TDC

 

[1200 JOTA]

take 2 ...

#1 any cylinder at or close to TDC
#2 any stator / rotor combination that will trigger 10 degrees earlier

(you can reverse the stator if needed or change position of rotor (unless it keyed .. normally just press fit))

 

[piranha-bro2]

You absolutely sure you have compression on each cylinder correct for the firing sequence? Easiest check is to simply take off the tappet covers and ensure there is clearance on both valves and no rocker movement when you rock back and fwd around TDC. It sounds so much like what happens with the std points when you have the points firing the wrong coil (ie on exhaust stroke) ... you could simply swap plug leads to the opposite cylinder and try that.

 

[piranha-bro2]

Oh, and don't be concerned about the 180 config of the pickups - the ignition gear rotates at half crank speed (one rotation of the rotor = 2x crank rotatations - one complete four-stroke. Just duplicates the double points system.

 

[Laverda SF]

My question is why ! The stock Points Ignition could eaisly do 8000 rpm and you can fix it on the side of the road ?

 

[piranha-bro2]

Once you start having trouble like Lyndonell is, I must agree with you, Ron - and Paul!! If my experience with elec ignition was so stressful I would never have done it. Mr Todd has no doubt done a million km on Boyer systems, ne c'est pas, Phil?