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How much advance on your 250?
Posted: Tue Mar 27, 2012 4:34 pm
by Bevel bob
My 250 is in Mach1/ Mark111 tune, I know that other owners use between 32 and 40 degrees, i'm using 38, I suspect those using 32 are trying to give the big end an easy life, I think 40 would give more top end but my big end has done a big mileage so i'm being carefull till the next rebuild . What do you do?.
Re: How much advance on your 250?
Posted: Tue Mar 27, 2012 11:51 pm
by JimF
Hi Bob,
I have the Mach 1 at 8 degrees but it certainly must have the AAU unit behind the points.
My non-descript 250 with no AAU whatsoever is at 39 degrees.
Jim
Re: How much advance on your 250?
Posted: Wed Mar 28, 2012 12:12 am
by DewCatTea-Bob
" I have the Mach 1 at 18 degrees but it certainly must have the AAU unit behind the points. "
____ A real Mach-I should gave it's static-advance set between only 8 to 12 degrees before TDC, NOT "18 degrees" !
Cuz in combo with it's stock 28-degree AAU, the 18-degrees static would make the total ign.advance TOO great (at 46-degrees BTDC) !
__ However if a 18-degree AAU is employed instead, then the resulting total ign.advance is okay,, but then that should mean that the Duke's ignition-system ought be as that of a Mark-III, and since that's the MAIN difference between a Mach-I & a Mark-III, THEN the Duke ought be referred to as a 'Mark-III' (rather than a "Mach 1") !
Dukaddy-DUKEs,
-Bob
Re: How much advance on your 250?
Posted: Wed Mar 28, 2012 1:03 am
by JimF
Oops! my bad fingers - I have fixed my post.