Jetting with Fatboy 4

[tywebb3]

Duncan's instructions say to use a 170 main jet with the Fatboy4 and the air box lid off. I was running a 150 main with the stock pipe before and the air box lid on. The engine is stock except for a sparks timing key.

My question is that seems like a big jump in jet size. Considering the change to the full exhaust and removing the air box lid, does that sound right? How many sizes would you drop off the 170 main if the air box lid was left on?

Thanks

[trx400Rider]

That sounds about right with the lid off. Try the 170 and go from there