[Diy_efi] Estimation of spark advance

[William Shurvinton]

Hi Carsten,

Don't worry about your English, as mein Deutsch is nicht gut, but my Bruce
is getting much better and i can usually translate him into European :-)

Can't vouch for Perry, but Bruce has built and tuned an awful lot of engines
so has something guys like me lack: experience. Someone somewhere once wrote
that optimum spark tuning is up to the edge of knock and back off 2°. So
that then becomes accepted wisdom, without dyno data to really back it up.
And whilst it is probably a very good rule of thumb for racing engines that
get rebuilt every few 100km it may not be the best compromise for street
use.

Your bike is not a fireblade/hyabusa and therefore you are probably more
after reliability than the last HP. You want good manners when you ride it
etc. So the optimum spark curve for power may not be what you are after.
Also if you are flying close to the wind it helps to have a guaranteed fuel
that is always the same (I read that so it may be wrong, but makes sense).

Was that about right Bruce?

Bill
----- Original Message -----
From: Carsten Beth <Carsten.Beth at Informatik.Uni-Oldenburg.DE>
> > Motorcycle
> > (touring) is going to be conservative, tune wise, an increase in timing,
> > might just get you some galled rings in stop and go traffic.
> >
>
> What do you mean with _conservative_? Do you mean it's better to give
> less
> advance? Perry Harrington writes in the same thread something about 2°
> less
> than the point where the engine begins to ping. Would you give less than
> 2°?
> And (sorry, my english isn't really good, how you surely noticed) what
> do you
> mean with galled rings?
>
> Carsten
>
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