Just had a Dyna run the other day with a air/gas analyzer. 2001 HK 2 3/4 straight pipe w/baffles, ported intake manifold, BAK w/167.5 main jet, clip on 4th pos., PMS @ 2.66 turns.

Baseline on test = 13 (over 13 is lean)
Results: (test done in 3rd gear)

20 to 40mph = 18 (extremely lean)
42 to 60mph = 14 climbs to 15 (lean)
60 to 85mph = 15 climbs to 16 (leaner)

I am not getting any backfire, none! Nada!
After reading the article about "dialing in your PMS" I'm starting to wonder, how accurate the test was?? 5 points from 13 to 18 seems a lot to me, maybe it is not, and I just need to turn out the PMS a little more, and I know some gas bleeding will go to the other carb circuits, hoping not to tear into the carb again if I don't have to.

Now what?? Do I go to a 37.5 pilot jet or 40??
What about the PMS?
170 main jet w/needle clip on 4th pos??

Any help would be much appreciated,<br><br>Post edited by: Erbman02, at: 2005/04/17 07:39

If they whacked it open (WOT) for the Dyno, the carb circuit operating is the main jet at higher RPMS and initially the needle circuit, until the CV slide opens.

Your readings call for a richer main jet and maybe #3 on the needle.

If they held part throttle (around 1/8th) and gave the motor time to burn off the pump squirt (generally reflecting cruise operation), then your PMS and pilot may need to go a little richer.

If you got a reading at idle, you could dial in the PMS.

AFR at 14.0 seems to be the mark for V-Twins. That's a little richer than other tuning practices, but it was recommended to me by Tim at Barons and seems to work on bikes I've tuned with an EGA.

Sorry, but I wouldn't leave the carb alone with those lean readings.

Jim

I've been trying to richen that lower circut for a long time and going to try a Maxmix screw but its said a 40 pilot will to do the same. Tried the #40 pilot and not satisfied.

One of our top writters/mechanic says &quot;its very hard to lean this engine enough to damage it&quot; it just won't run if its that lean but I stand to be corrected.