Hey All,
The snow just left my area and I'm able to try out all the stuff I put on over the winter -- I have a jetting recommendation request:

I have an 04 Roadie
Speedstar 2 into 1 pipe
Speedstar Air Filter Kit
Baron's Jet Kit
Don't remember the turns on the PMS

It seems to run just a little rougher than stock. Minimal backfire. Slight hesitation at about 1/4 throttle.

Any suggestions?

Hi Tamaule, what jet size did you use and the setting on the needle? Did you plug up your AIS?

Big Al,
I'm not sure what is in it now. It was installed while I had the stock, drilled pipes on it and no air kit. The 167.5 main is missing from the kit -- I'm guessing that's what was used.

Yes I did take off the AIS and plug it up. This was done at Star Days the same time they did the jet kit.

I was going to start with 172.5 Main, PMS at 3.5 turns and the Clip on #5 and see where that took me.

It's hard to tell where it should be with the temp being so low. 40 degrees is a good day here. That kind weather can make your bike run a little lean anyway.


Tom Maule

Tom, thats a good setting to start at with that size jet. I did a friends 04 Roadie and I set the PMS at 3 turns out. He is running the stock headers with Cobra mufflers and Kury TV. Also, turn your accel pump screw all the way in to the nut. Good luck..

Al,
I decided that before I started dinking around with it I should do the standard WOT test. In 4th gear at about 80mph backing off on the throttle just a bit didn't change anything - didn't feel any increase in speed. Using the 167.5 Baron's Jet. I set the PMS at 2.5 turns out and don't get any backfire when free rapping the engine - If I open it up in 3rd gear and let off the throttle completely I get a sports car sound (not really a backfire).

I do have a little hesitation when I try to maintain speed (just above 1/8 throttle) and sometimes when I first take off it will die. Do you think this could be the needle setting is bit lean or is this the accel pump setting?

Tom, it could be the accel pump setting. Remember to change one thing at a time. I cleared up the carb cough by turnng in the screw to the nut. What elevation are you at? If you are less than 4000ft. use the 172.5 main from Barons. Your Speedstar air kit is a good flowing air filter as I have the one from K&N and it is the same. My bike is a 2000 model which I bought new and has run great from the first day and after every upgrade I've done to it. Your hesitation could be from the sudden blast of fuel from the accel pump when you first twist the throttle. After you solve your 0-1/8 throttle hiccup, deal with your needle setting. Mine is set on 5th clip, spacer-donut-spacer and I'm getting great mileage and great throttle response. My PMS is @2 3/4 turns out, of course I had to fiddle with the carb settings plenty until I felt a good combination was in order. Good luck..

Thanks Al,
I'm at 1300 ft. That's a mountain in MI. I will try the larger Main Jet - like you said "once I get the cough cleared up". Dealing with software all day I know the dangers of introducing too many variables at one time. I am a little worried about the MPG. I am getting 46.2mpg right now. I would be a shame to loose that.

Thanks for the good advice. I’ll be working on it later this week – we are getting a little snow here (blah!)

trying to fine tune your roady's carb can be a voodoo type of experience, once you're close it's all about your specific roady and your elevation and your riding style... like performance, go rich, like economy, go lean... I think everyone will have an opinion about your settings and of course, here's mine.

I think a lot of people keep their roady to rich, the engine will run richer than any other motorcycle engine I ever known... but even though it will run great, eventully you will have problems with carbon build up and the infamous "sticky exhaust valve"... if your not having any problems running wide open (it'll stutter and feel like you need to switch to your reserve, if your WOT test doesn't accelerate when you back off of a slight bit I don't think you need to change your main jet... you main only has an effect at fuller throttle positions... do I think a 172 is to rich, not enough to give you the sticky valve (especially if you ride it like you stole it), but your pushing it, and you'll get less gas milage (I got in the 43 range)

about the accelerator pump: if you watch what it does, it will inject a squirt of fuel when you open the throttle, and only when you increase how much the throttle is opening. Because there is a hesitation between the throttle open and the vaccume lift of the needle out of the main jet, there is a moment when your engine is getting to much air, and not enough fuel (the venturi effect takes a moment to catch up to the sucking air). I do believe that the pump does dump a little to much fuel into the carb, but I don't believe it should be eliminated. I also believe that the timing of the pump injection can be delayed especially if your getting a fuel spray back into the air cleaner (all of the articles say you shouldn't need to do this)... I think if you need to eliminate the accelerator pump you are running to rich on your PMS... because during this "lean moment" your mix is actully good, and the injection of fuel by the pump makes it way to rich (drowns the engine)

If I read your post correctly, you said your bike hesitates at constant speed about 1/8 throttle (not when you increase from 1/8 but when holding RIGHT?) If thats the case IMHO your hesitation at 1/8 throttle is probably due to a PMS circut thats not tuned. how I'd figgure out the way to adjust it would be to LEAN out the mix by going in on the PMS and then taking it for a ride and see if it makes the problem worse, it sounds like it may be to lean (most of the time people set it to rich because they tune the PMS with the air cleaner off, then when you put the air cleaner back on it limits the air intake, and hence a little richer pms). Here is another test, can you start your bike with the choke / enricher off or at 1/2 setting, if so, to rich on the PMS. (do this test at your normal riding temp)

Well I apologize about the length of this post, and I hope in some way I helped you, but truly you need to first know all of the intricate details of your carb, then all of the intricate details of your bike, then know all of the intricate details of your riding style and adjust from there.... if you know some person who knows this, please let me know... I sure as Hell don't! the person I think knows the most would be ODO... and even then I disagree with him in theory occasionally (not that I'd post against him - respect issue) but like I said, we all have opinions... most people eliminate the accel pump, my thought is that the mikuni people thought it should be there for some reason, and they probably know more than me ~Guido

Even if you turned in the duration screw all the way, you would not be eliminating the accel pump function. You would still get a squirt of fuel but less in duration/time, hence the name duration screw. The Mikuni 40BSR CV carb functions with all circuits bleeding fuel all time you just get the amount of fuel needed as you twist the throttle 0-WOT(from pilot through main circuit).<br><br>Post edited by: Big Al, at: 2006/04/04 18:01