pilot jet Q

[snofrog]

say you are at 4 turns out on the enrichment screws and go to the next size up pilot jet . where would the initial screw settings be for the new jet ? Mark

[tannerismyhero]

stock on a 12 I believe are 2.75

[Red01]

^^^ That'd be a good place to start. ^^^

[snofrog]

I guess I`m trying to get a handle on how much difference one jet size makes ie if I`m maxed on my pilot jet now would I be in the middle,top,bottom of the next size up . dialing it in wont be an issue ,I just want to make sure I go up enough , ya know ?

[rider123]

Stock for me was around 2.25 just to let you know. I'm at 2.5 with snorkle in and a slip on. I've seen some guys here as low as 2 turns out pm a stock bike. So 2.75 should be pretty close. I think I saw a chart once (or maybe post?) that when you go one size up it's the equivilant to 1 1/2 turns out on the size down.

E.G.
4 turns out on a 15 size pilot would be 2.5 turns out on a 17.5.

I'll try and find it at the factory pro site.

[Bazza]

I have increased the Pilot jets on my 2002 B-12 to 17's (next size up from the 15's)

Now here is the thing.

Increasing Pilot jet size will only help you get a better idle.

From all I have learned that if you can obtain a smooth idle at 4 turns out or under, you will not gain anything by increasing your pilot jet size, other than you may get by with 3 1/2 turns out.

What most say, and I would agree from my own experiance is that after 4 turns out on the screws with stock pilots, the metering of fuel becomes less exact. So you add the larger pilots to allow more fuel in at the same setting.

Really, I did not notice a heck of a lot of difference with the larger pilots as far as turns out. Yes, there is a difference, but it is not one in a half turns. I found maybe a 1/4 turn out.

I have an Ivan's jet kit in my bike, with his airbox mod, 112 (I think Mains) which came supplied. needles on the 3rd clip, and I added the 17 pilots to the equation.

Now I spoke with Ivan when I was tinkering with the bike after I installed the kit & his advice on setting the a/f screws was to turn them out enough until you get the smoothest idle on the bike. I took his advice and mine idles best with the screwn out 4 5/8 turns. (I will likely increase the pilot jet size further sometime down the road).

Keep in mind, a pipe & airbox mod changes things drasticly.

From my experiance, I would recomend maybe a 1/4 less than what you had stock.

Now keep in mind, I have done a rather huge airbox mod and the reduced resistance in the airbox from stock does have an effect on idle. (I am not sure if you have done any airbox mods) A/f screw adjustment will probably be more touchy on a stock airbox.

But from my experiance, unless you are past 4 turns out (and the bike idles well) Increasing the pilot jets size is not going to give you anything.