Curtis Sparks Jetting

[Mercedes]

2006 400ex with Curtis Sparks. Backfires when let go of gas.Got stock 38 pilot and 142 main. Was told to go to 45 pilot and 155 main by guys at sparks. Once i do that how do i find out if its OK. I wanna keep my lid on,never know whats arround the next corner here in Quebec.

[Franky G]

Yea bump up the pilot a couple sizes same with the main jet

[tar]

I have a full Sparks with a K&N w/ open airbox and I run a 158mj so you should be good with a 155 main so bump up the pilot to probably 142 or so.Hope I helped.