Author Topic: Rejetting a 38mm A/S need help (Read 4345 times)

steelreign · « **on:** May 19, 2014, 12:52:15 PM »

I have read a lot of posts on here explaining what needs to be done so I think I have a pretty good idea. The problem is that it seems really rich and will not stay at an idle and is real boggy from 0 to 1/4 throttle. My set up is.
265cc with MX port
Rad valve with spacer
ESR MX pipe and silencer W/ eliminator
32/1 mix ratio Castor 927
93/110 octane 50/50
38mm A/S with 165 main and 58 pilot
Clip is on 2nd notch from the top
Air screw 1 1/2 turns
Slide screw 2 1/2 turns

So I guess my question would be does the jetting seem way off? I believe i need to go to a leaner pilot jet but should I mess with the main jet? Any help would be appreciated.

Bowtie316 · « **Reply #1 on:** May 19, 2014, 12:56:50 PM »

Pilot seems rich to me, have you adjusted the air screw to find where it likes to be? What needle? I wouldn't lean out the main jet just yet.

steelreign · « **Reply #2 on:** May 19, 2014, 01:04:02 PM »

Yeah the pilot seemed rich to me as well. I am not sure what needle I have but can check tonight. I forgot to mention the elevation is less than 1000ft. I have tried adjusting the air screw and in one spot it will idle but it is a very weak idle at very low RPMs and it still wants to die.

PORTED R · « **Reply #3 on:** May 19, 2014, 05:44:28 PM »

Pilots too big
Needs to be around 48 to 52 range
Depending on climate,elevation...etc
Problem is your loading up with that huge pilot
Needle and main seem good
Won't know 100% in tell u get that pilot and idle right

udontknowme · « **Reply #4 on:** May 19, 2014, 09:23:39 PM »

58 seems way out in left field

08IRS · « **Reply #5 on:** May 19, 2014, 11:06:12 PM »

I just received mine and it came with a 48 pilot and 185 main

TRXforever · « **Reply #6 on:** May 20, 2014, 08:01:18 AM »

My 38 A/S came with 48 pilot, a 160 main, and a DEK needle. I threw in a 52 pilot, a 178 main, and a DGH needle middle clip . I am still trying to get mine to idle too. Going to drop to a 50 pilot and try it again. I am running Paul Turner Hyperdyne jug with a 69 piston & 19 cm dome , rad valve (no spacer) CF reeds, LRD adjustable pipe and silencer, K&N in the box with outterwear and outerwear lid, B8es plug, and 112 race gas.

JesseA420 · « **Reply #7 on:** May 20, 2014, 08:32:40 AM »

pilot jet like everyone else says.

mx250r91 · « **Reply #8 on:** May 23, 2014, 02:04:08 PM »

I have a similar setup, 85 jug 68.5mm (265cc) slightly ported, high compression. With the 38mm PWK A/S right now I run a 45 pilot and 175 main. What needle are you running? The needle straight diameter as well as pilot jet have the most effect on your 0-1/4 throttle jetting.