Port Timing for a 220 ? BBDC, ABDC (low speed)

[johnkdx220]

Ok, winter is way too long and I decided to study my owners manual for the 2003 Kdx 220 and compare it against the Service Manual Supplement for a 2002 Kdx 220 (the 2003 service manual was not printed at time of purchase).

I have 3 questions regarding port timing:
1) What does BBDC, ABDC mean?
2) What is the correct ABDC (low speed) for the 2003 220? The owner's manual indicates 78,8 degrees while the service manual shows 79.7 Degrees?
3) How frequently must this be adjusted?

Any help would be appreciated. Thanks.

 

[shr]

I think this is what you are asking for your question #1

BBDC = Before Bottom Dead Center
ABDC = After Botom Dead Center

 

[Robcolo]

John, You don't really ever "adjust" port timing. It never changes unless someone takes a grinder to your ports or you slip in an extra base gasket. It's the measure of the piston passing a certain point on each of the ports