CA vs. 49'er advancer - Any difference for Mod?

[Pkaaso]

Probably a question for Bob B. but any comments welcome.

Q: Is there any difference between moding the CA advancer vs. the 49 stater?

Just wondering.

Thanks,
Paul

[pantablo]

Bob posted the following in the thread called "sent out advancers, non in return" (or something like that), on second page of threads...

"There are 2 styles of rotors for the GS500.
The CA rotor is set to 5 degrees btdc and the tab is wider for 35 degrees dwell.
The other model is set at 12 degrees with a tab width for 28 degrees dwell.
The V&H is set at 17 degrees with a 28 degree dwell.
I fill the stock crank pin groove on the bottom of the rotor and drill a 3mm hole to relocate the pin and advance the timing. The weld needs to be milled flush to fit cleanly o the crank. The new pin hole is located halfway into the stock groove, so you have to weld it up. The pin location is critical. A small misalignment equals several degrees.
On the CA rotor I mill the tab down to the width of the V&H rotor.
I mill on the side where the tdc mark is. So the tdc mark is advanced too. I take a hacksaw and make a cut where the new tdc should be.
The timing advance is controlled by the black igniter box to a total of 40 degees btdc. The rotor timing only effects the lowend from idle to 3000 rpms.
I don't see any benefit from an adjustable advancer."

[Pkaaso]

Thanks Pablo.  I really should read more.

OK to that question.  How can I tell the difference between a stock CA and a stock 49'er?

Paul

[pantablo]

The CA rotor is stamped 5-35 and non CA rotor stamped 12-28 (in reference to the btdc and dwell settings of each.

[Pkaaso]

Cool thanks.  I got a 12 degree yesterday and checked it against the 5 degree.  It is just as you said.

Thanks,
Paul

[Lars]

I don't understand one thing: how is it possible that only the lower rev range till 3000 rpm is affected?

As mentioned the black box controls ignition advance. But it sends ignition pulses based on the position of the crank. if you change the position at wich the rotor gives a pulse to the black box, how can it be that only the lower rev range is affected? at 10K rpm the rotor still sends a pulse 5 degrees to early.