I ordered up some main jets in 170, 160, and 150 sizes to give me a rough idea of what I was looking at. In the 170 package, I received a 180 along with the 170. I have since received the correct size but I haven't tried it yet.
I immediately noted a change in the engine note and feel with the 160. Redline came easier in 3rd and 4th gears with a more eager note. When I tried the 150's, I noticed the upper rpm response was dull and and rpm increased when I backed off from WOT as the mixture richened. Definitely too lean.
I'm going to order some 165's to see if anything changes. My riding season temperature in Michigan ranges from the low 40's to the 90's so the 165's might like the cool, oxygen dense, late fall air.
Does anyone have any other jetting combinations they'd like to share??
89 BMW R100RS
97 Suzuki DR350
And away we go!