Topic: Rejetting my 550F for a 4-2

[Clinto]

So, I'm replacing my stock exhaust with 4-2 headers with EMGO reverse cone 17" mufflers which I'm going to pack with fiberglass to quiet them down. I'm assuming that this set up will be more constricting than my stock 4-1, so I'm wondering how I should try to rejet my carbs. I don't have the numbers in front of me right now, but I know all my jets are currently stock size. I think the sizes are something like .38 and .92

I was hoping to get suggestions on where to start. Whether I should just run them with the stock jets to see how that works, or go ahead and buy some smaller jets to compensate for the more constricting exhaust. And do you always change the size of both the slow and main jet at the same time or should I just start with one or the other and go from there. Thanks for any info or general advice, as you can probably tell I've never done a rejet before. Thanks

[calj737]

Should be 98s if I recall correctly as stock. Probably only need to adjust the main jets after a good plug chop. 4:2 should also be less restrictive than the 4:1

[Duanob]

Should be 98s if I recall correctly as stock. Probably only need to adjust the main jets after a good plug chop. 4:2 should also be less restrictive than the 4:1

The same size main is used for the 4 x 4 set up as well. Probably don't need to rejet the main at all. You might need to reset the needles one clip position.  That's really the only diffence between the 4 X 4 and 4 X 1 set up. The 4 X 4 uses the 4th position, the 4 X 1 uses the 2nd. I would guess the 3rd position. You will need to do a vac sync after playing with the needle jets.