Sachse ignition

zrx1100

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Is anyone using Sachse iginition? Seems like a very suitable option for modified motors as it allows for a variety of advance curves. My higher compression 700cc project (https://www.xs650.com/threads/700cc-kit-with-a-shell-1-cam-in-a-78xs650e.65405/) with a Shell cam likes stock advance at idle, but less advance than stock at higher rpm. I am running pamco with the stock mechanical advance.
 
I have heard of it ,But don't know anyone use it To expensive I do believe
if you search on Google there are some hits .can be in German that needs translation That Webb program have

sachse zundung probleme

?? Restrict the stock advance movement ?? If it goes all in at higher rpm some shims makes the advance lower
 
In the meantime, I retarded the ignition a few degrees. As many in this forum, I have set the idle to the right edge of the idle range, somewhere between 10-15 degrees. The full advance is between 35 and 40 degrees. The bike likes it. Any less advance and I need to adjust idle, which is not really an issue, but I will wait to check on the dyno to see if I need to reduce the full advance further. To help with the measurements I made a cutout of a sized degree wheel and aligned 40 degrees to the left edge of the cutout on the engine case and zero at the TDC mark

At idle

1707805360329.png


ad full advance:

1707805446175.png
 
Sent Sachse an email with a few questions about which curve is suited for what motor configuration and which one is recommended for a stock motor.
None of the curves seem to be exactly the stock advance (10-15 degrees at idle and 40 degrees at 3K rpm). Lets see what they reply
 
Here is the prompt response from the company:

wrote:

Would you be so kind to help with a few questions: Do you have any
dynamometer data to show how the various curves programmed in the
XS650 module affect the performance?

Sorry, we don't have dyno run data for the XS650. We have ran
several models on the Dyno, but not the XS650 as I'm aware.

What engine tune/configuration would you say each of the curves is
best suited to?

That's hard to tell. People change carbs, exhaust systems, modify
the heat, lighten the crankshaft weight, etc. All this changes the
behaviour of the engine and it requires different advance. A tuned
racer might require different advance than a road tourer.

We try to offer suitable curves for different use-cases. But I don't
have information which combination which curve is meant to cover.
Not all curves make sense for a given model. Curve 1-3, for
instance, are not suited for the XS650 if you ask me because it's
just not enough advance for that engine.

The choice of curve depends on the complete system, engine,
carburettor, exhaust, tuning, mono or double plugged heads, tuning,
etc. Furthermore, it depends on your personal preferences. Different
curves might be applicable on the same bike for different driving
characteristics, e.g. racing or touring.

Dual plugged heads require less advance. Apart from that it's not
that easy to find the optimal curve. Different curves change the
characteristics, so it's not easy to pinpoint a curve being “better”
than another one, rather than “different”. A dynamometer surely
helps determining a good curve for the bike and use case. Just
trying different curves on the road works as well. Notice that some
curves only have subtle differences and you might not actually
notice a change.

We ship the units with a suitable curve for the purchased model as
default. If you don't want to fiddle with the system, just leave it
there. It is a conservative curve with not too aggressive advance so
it does a good job as default curve for a variety of bike
configurations.

None of the curves seem to be exactly the stock advance (10-15 degrees
at idle and 40 degrees at 3K rpm).

Correct. Our curves rarely match the stock curves. We find that
stock curves were usually based on mechanical ignition restrictions
as well as fuel quality from 50 years ago. Usually we can now get
away with less advance at high rpm and also less advance during
engine start. Practice has shown that it works better that way.

Which one do you recommend for a stock motor?

Curve #6-#9. I'd start with #7.

Regards,
Marco Patzer

--
Elektronik Sachse MHP GmbH & Co. KG USt.-IdNr./VAT: DE815480713
Busestraße 26a HRA 28131 HB
28213 Bremen Gerichtsstand: Bremen
Germany Phone: +49 (0) 5409 9069826
Web: www.elektronik-sachse.de
 
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