My new Monster

Just added a M900 to my family so thought i would just say hello.
After my 916 which was a great bike, this is a dream, no more sore backs.
The only prob i have is shes running too rich, she coffs and splutters at low revs but goes like stick when pushed.
but you cant always be on the gas.
I have a open air filter and a modified zorst system with d&d end cans.
Not sure whether or not to take her back to standard or she just needs setting up properly.

Better rich than lean!!

Take back to standard? Oh dear me no.

I had done the mods you had and yes, just needs setting up a bit. You could try dynojet stage 2, or just get an expert to fiddle with the mixtures.