A
Anonymous
Guest
My 170 wants a TON of initial timing to run right. I have an Offy with three 1909s, and a custom made cam. I don't have the card in front of me, but it is somewhere in the neighborhood of 250 duration, with about a .425 lift on a 108 degree lobe center. It runs with the tining set at 8 degrees, but it idles really rough, and continues running rough up until about 2500 RPM. The more timing I put in it, the better it runs, meaning by adding another 8 degrees, it starts running right by 1500 RPM. By adding a few degrees more, it merely idles rough, but when accelerated, it smooths right out.( I understand bigger cams will make it idle rough, but this acts more like a miss than a lopey idle) I don't even know what the timing is now, its so far off the pointer I can't read it. Is this normal? should I just accept it and be happy it runs well( other than idle)? what are your experiences with initial timing and aftermarket cams???