SF1 Ignition Timing

[ColinJ]

I have a question about setting the ignition timing on my SF1. I have followed the method in the green book and the points now open when the PM mark aligns with the mark on the crankcase. My question is, statically the engine is set up to spark at TDC, but I assume as soon as it starts the mechanical advance unit will advance the engine accordingly and achieve a maximum advance of 29degrees BTDC at 3000rpm. Is this correct?

The reason I ask is that I am more used to old British bikes where for example on my old T120 the static value is at 14degrees before TDC and it seems strange to set the SF1 at TDC.

Also is dynamic timing with a strobe recommended for the SF1?

 

[Exmoor beast]

Correct, they fire at TDC- then advance. Strobe it to check advance, you can alter advance mechanically as well.

 

[Ernesto]

Max. advance is 40°, reached at approx. 2800 - 3100rpm.
Most flywheels have a mark(A).
So, if your ignition doesn't reach 40°, you should inspect and clean
the advance unit

Ernesto

 

[Paul Marx]

Check that the PM mark is indeed TDC.

Paul

 

[Exmoor beast]

The reason I ask is that I am more used to old British bikes where for example on my old T120 the static value is at 14degrees before TDC and it seems strange to set the SF1 at TDC.

Remember Laverda 750 was first electric start only bike, firing at TDC gives the starter an easy life and works remarkably well..unlike electric start Norton Commando.

 

[Paul Marx]

Remember Laverda 750 was first electric start only bike, firing at TDC gives the starter an easy life and works remarkably well..unlike electric start Norton Commando.

Retrospectively, a silly idea aka a sales gimmick.

Paul

 

[ColinJ]

Remember Laverda 750 was first electric start only bike, firing at TDC gives the starter an easy life and works remarkably well..unlike electric start Norton Commando.

That is interesting, I didn't realise the retarded ignition would make it easier to start but it makes sense. I have never had a commando with Dr Lucas's electric foot but they do not have a great reputation.

 

[ColinJ]

Thanks for all your replies, they make me more confident I have done the timing properly. I will strobe it today to check the advance.

 

[CLEMTOG]

You dont say if you have a double points setup, or if it has been changed to an aftermarket electronic. The Boyer system supplied to Dave Mintons (Slater) test bike and the one I bought from them (both long before Phill Todd was in an arrangement with Boyer) used a box from a Norton Commando kit, hence insufficient full advance and why my Egli went back to points.
CLEM

 

[piranha-bro2]

Just a std SF1 I think Clem.

 

[ColinJ]

Check that the PM mark is indeed TDC.

Paul

I did check it and it and it is TDC

You dont say if you have a double points setup, or if it has been changed to an aftermarket electronic. The Boyer system supplied to Dave Mintons (Slater) test bike and the one I bought from them (both long before Phill Todd was in an arrangement with Boyer) used a box from a Norton Commando kit, hence insufficient full advance and why my Egli went back to points.
CLEM

yes it is double points.

 

[1200ts]

I did check it and it and it is TDC

yes it is double points.

Make sure you lubricate the auto advance shaft with grease. Most people don't as part of normal maintenance and wonder why it is now clapped out and the bike runs like shit.