416 backfiring

[la400ex]

I just installed my 416 ross piston and hotcam stage 2. My other mods are in my sig. I have been doing the heat cycles trying to break it in. I can tell it has more power. I havent really broken it in yet. I have a 170 main and a 42 pilot. I didnt change the needle. It is backfiring really bad. I didnt think the 170 main would be lean. Should I try a 175? Thanks, Ant.

[la400ex]

Oh yea, forgot to mention that it wont idle and kills as when i let off the gas. Im going to check the plug tomorrow and see how it looks. I cant wait to get this thing dialed in. I want to see if it is any faster. Thanks, Ant.

[Ex'r Marlin]

Just my 2 cents... Do the recommended break-in, and after you have her broke in, let us know how your 416 is running.

Note: I too am surprised to hear that it is backfiring on you with the jets that you have.:confused: Do you have a 175 main? If so, I personally would try that and see how it runs.

Good luck... And keep us informed!:)

[la400ex]

I dont have a 175, i didnt get any bigger than a 170. I thought that would be a little rich. Im going to go out there now and check for any leaks that could be making it lean. Thanks, Ant.