Another thing to add is that the 1 3/4" exhaust is too big for your engine and you could actually loose power, 1 1/2" all the way through is plenty big enough - which is what I have on my 1098.callyspoy wrote: ↑Sun Dec 23, 2018 12:04 am Panky, i didn't want to suggest it as i hadn't done it myself before, but that is what i would do also.
Slight thread hijack...
My own Minor is a 998cc, 940 head, 1098 cam, HIF38 with K&N cone filter, AAA needle, Ital twin outlet exhaust manifold going into a 1.25" exhaust system.
Could the exhaust be restricting the engine enough to mean the AAA is too rich? I know it is too small diameter for optimal power, and i have a 1.75" RC40 twin box exhaust system to modify and fit, but i thought it would be ok for now, but the plugs definitely do suffer a bit. The tip is a decent enough brown colour, but it is quite black everywhere else.
I don't want to buy a leaner needle, only to find that the larger exhaust will allow it to breathe so much better that the AAA will be more suitable. (Partly because i accidentally sold a spare HS4 without removing the AAU needle that i had, idiot).
So many things have been changed from standard that it will be difficult to get an ideal needle/spring set up off the shelf, best you can hope for is somewhere near but ideally a rolling road session is needed to set it up properly. It could be that a custom needle will be needed to get the profile required throughout it's full length.