Author Topic: 81 cm400c rough idle, backfire  (Read 327 times)

Offline Nmills

  • Posts: 1
81 cm400c rough idle, backfire
« on: May 20, 2017, 00:04:44 »
Hello, I am building a cafe racer out of a honda cm400, I replaced the airbox with two come filters on the carbs and got some less restrictive exhausts. The bike sat for 7 years in a barn, I rebuilt the carbs and it ran great but after putting the cones and exhausts on, it's only firing on one cylinder at idle. If you give it gas it runs rough until it revs up to around 3k rpm which is when the second cylinder kicks in. I have a new coil in the mail and it will be replaced just to rule that out. Any suggestions would be very much appreciated!