07 z400 running rich

[powsmitty]

Hi I just bought a 07 z400 that has some mods done to it but I don't what they all are and is running rich. From what I can see the air box has the back cut off and it has a KN filter with Outer skin pre filter and maybe the stock exhaust has been tampered with but I don't know. I pulled the plug and it is wet and black. I seemed to run fine the short 20 minutes I rode it at the dealer but I want to fix this issue. I would assume that either an aftermarket exhaust or a new jet would make it run proper. Do you think a complete stock air box make it run proper? Also does the petcock have an off setting? Mine says on/pri/res.

[cataway]

it would help if you would tell what jets you have in it now

[powsmitty]

Not sure of the size. I've ran around 5 gallons of gas through it today and checked the new plug and it seems to burning better. Going to run 5 more my next few days off and check again. Don't know how old the plug was or how long it was run with choke on prior to me buying it that day. Thanks for your reply.

[powsmitty]

After 10 gallons of fuel it seems to be running good. Good color and the temp is okay.