My '98 919 has a K & N and a Yoshi Slip on. #40
pilot jets and #125
main Jets and mixture 2 1/2 turns out. Factory needle and single washer.
Now, with this set up, it runs a little rich at about 3750rpm causing some fluffiness at cruise. I used different mixture turns and it made little difference. I put 2 x extra washers under the needle, now it bogs down at take of and has fluffiness at 2500rpm and 4000rpm.
So my questions are:
a) Should I get rid of the K & N filter and put a stock filter back in?
b) If I remove ALL washers, from under the needle, and put #128
mains in it, should this solve the issue? If not, could you explain what part does what function, at what revs.
Thanks in advance