Advice on 40 pilot jet and 170 main jet

[rinaldi]

I am installing a full AC system today along with an open box style lid and the dealer sent me a 40 pilot jet and a few main jets; 155, 158, 170. They screwed up and were suppose to send me a 165 and 168 not the smaller 150's. Anyway I planned on installing and trying the 170.

I read the posts on jetting, but still somewhat confused since I have never jetted a carb before. I will tear it apart, but what would be a good starting point for jetting and adjustment for my setup. It's an 06 with a Uni filter w/outwears, open box style lid, full exhaust and live in IA (midwest with riding temps 60-90 and mild humidity).

[rob_990]

id start with the biggest one then keep going smaller till it runs the best at almost full throttle

[BEAVER.989]

158 sounds about right to me, actually.

[bigd's ex]

I agree with Beav on a 158, that should be real close. I run pretty much the same set up as you except for a 2Bro's pipe. They sent me a 170 with it, but after alot of trial & error I am now running a 158 main ( keihin ) , 42 pilot, & 2 3/4 turns out on the a/f. clip is 3 down on the needle. Like Rob said also, start with your largest & work your way down.

Here's a link that might help ya.

http://www.duncanracing.com/techfaq/Tech_keihin-carburetion-jetting.phtml

[rinaldi]

I installed the 158 and pilot. What size is the stock pilot? All the jets they sent me are the Keihin. Also, I have not adjusted the a/f or clip. What effect does the clip/needle and where on the carb is it located?

Initial test the bike fired right up. Not sure how she runs since it is raining and my daughter is napping.

[BEAVER.989]

To access the needle you'll have to open up the top of the carb, but I don't think the needle will need to be messed with until you get into more significant mods.

I just installed a slip on and filter and removed my choke. I adjusted the needle, rode it a day and then returned it to it's stock position and it seems better now.

With a 40 pilot, I'll bet you'll want to have the fuel screw somewhere between 2 1/2 and 3 1/2 turns out.

[rinaldi]

Where is the a/f screw located on the 400? Is it near the bottom of the carb and can it be accessed without taking everything off? And it would be turned out correct?

[BEAVER.989]

The fuel screw is at the bottom of the carb towards the front. On 99-04 models it's a slotted screw, while 05-up models have a D shaped screw. I'm afraid if it's a newer one, you'll have to remove the carb to access it... and make, or buy a special tool for it. You'll want to start by lightly bottoming it out and then count turns outward.

[BEAVER.989]

Here are a few good reads...

http://www.thumperfaq.com/fuel_screw.htm

http://hmfracing.com/forums/showthread.php?t=497

http://hmfracing.com/forums/showthread.php?t=680

http://www.exriders.com/vbb/showthread.php?s=&threadid=399592