Hey guys. I have spent a lot of time reading through the jetting posts and I think I am maybe more confused than when I started. To give a back story, I purchased my roadie from the widow of the original owner. The bike sat for over 3 years with no miles ('04 Silverado with 3500 miles all stock). I purchased V&H big shots pipes with baffles second hand and brought it to the local dealer. They put a Dynojet kit in it and after getting 22 mpg and smelling like raw gas, I brought it back. They said that if I wanted good fuel economy I shouldn't have purchased a Road Star. Heated discussions ensued and long story short, they did some tweaking and got it better but not great...but that's the last they will see of this bike. I am still only pulling mid 30's with mainly 55-65mph riding so I figured it was time to do the intake and jet this thing myself. I purchased an RC-1980, AIS removal kit, Barons Mixture screw, and emgo breather yesterday on Amazon(also got a grizzly valve for the future pumpless project) and it should all be here this weekend.

I have never re-jetted anything but do feel competent to try. So after reading posts that range from "throw away the DJ kit and go with Barons/mikuni" to "it works perfectly from the DJ directions" I am at a loss.
I really don't want to buy a whole new jet kit from Barons if I don't have to. I am pretty sure that the DJ pilot is in the carb. I think the DJ 170 main is in there right now. My home base is at 1150 feet above sea level if that matters. The instructions call for a DJ200 but I only see posts of guys saying that is way too rich. After a lot of reading, it looks like even the DJ190 will be too much. So is the 172.5 Mikuni main is the ticket for my situation? Should I just go back to the stock jet? Can a main jet be purchased separately without getting the whole kit? I don't mind going back to the Yamaha dealer for parts. Thanks in advance.
Adam

Yes you can and should use a Mikuni 172.5 main jet even with the Dynojat needle. Also purchase a Mikuni 37.5 pilot jet to install. Set the needle on either the 4th groove with the spacer and 1 washer under the clip or 3rd groove with the spacer and 2 washers under the clip. (either will work) You can use the washer from on top the clip as the 2nd washer. It's not important for the spring on top the clip to set on it, it will be fine without the washer on top. Then set the PMS screw to 2 turns out from being seated and you will be good to go. That should get you into the 40's mpg on a steady hwy cruise. and high 30's to low 40's if you are easy on the throttle in town riding.

Thanks for the quick reply. Can the main jet and pilot be purchased separately? Is there a part number I should be looking for?

I just went thru the same scenario, and the carb was a mess from sitting!!!! I have the same jetting as DaveJ stated and My RS runs like a Raped Ape. The fuel mileage is not that good when the carb is tuned for performance. Once I had the carb set where I wanted it (best performance) I was getting 30 to 35 MPG. I picked up the most MPG's bye a little leaner on the PMS and tweaking the acc. pump. (come on just a little later with a little less, and my mileage came up, BUT My performance off the line went down. It didn't hurt the top end just getting there. So I live with 35ish Mpg's, Very Good performance, and a big Smile every time I Crack the throttle...
Ps: I Haven't found the top end yet

Well... it sounds like I have a good starting point, however, my favorite local dealership can't seem to find the 172.5 main unless I buy the whole Barons kit. I think they managed to dig as far as the Yamaha microfiche because they explained in the voicemail that the stock jet is different. Ugh. The good news is that they found the 37.5 pilot. An interesting question came up however...the guy at the dealership said that the stock main is 182.5 (or something like that) and he questioned if i really wanted to go down to that small of a jet. I am not questioning the results that others have found, but I am struggling to understand the physics. I thought that by adding pipes and intake you introduced a lot more air...which would lean out the mix and require a BIGGER jet to shove more fuel in. Perhaps there is a simple explanation?
Either way....I am stuck now trying to find a 172.5 main. Can someone help me find that jet, or more importantly...(i really only have this weekend to work on this) if i have to stick with either the stock jet or go with the 190 DJ jet, do the needle and pilot values change significantly?

You use the smaller main jet because you got rid of the big fat stock needle and are now using a skinnier needle with more taper. The Mikuni part number is N100.604.172 for the 172.5 main jet.

If you have to live with one you have for a few days, use the DJ190 and drop the needle to the 3rd groove. Not perfect, but it'll do.

PJ Motorsports.com for Mikuni parts. Good prices and fast shipping. This is where I got my 172.5.

Thanks again everyone! The plan is to get this all done this weekend. I will report on my progress!

davej wrote:
Yes you can and should use a Mikuni 172.5 main jet even with the Dynojat needle. Also purchase a Mikuni 37.5 pilot jet to install. Set the needle on either the 4th groove with the spacer and 1 washer under the clip or 3rd groove with the spacer and 2 washers under the clip. (either will work) You can use the washer from on top the clip as the 2nd washer. It's not important for the spring on top the clip to set on it, it will be fine without the washer on top. Then set the PMS screw to 2 turns out from being seated and you will be good to go. That should get you into the 40's mpg on a steady hwy cruise. and high 30's to low 40's if you are easy on the throttle in town riding.

whew glad I don`t have to have that washer on top of the clip.
After much consideration I bought a Baron`s Kit so know I have no DynoJet
parts in there at all...just got tired of trying to tune it with that
needle and Mikuni or DynoJet jets....so
Baron`s needle 4th groove,washer,spacer.
172.5 main, 35 pilot, PMS screw 2 1/2 turns.
Thunder Mfg. Air Cleaner

Hopefully this weekend will get to do my 180 mile loop I like to do
and see where my milage is at. I`ve read differant opinions as far as
using the 35 or the 37.5 pilots.

Good luck with you jetting CNWMAN, all seem to vary a little.

vegasdave wrote:
davej wrote:
Yes you can and should use a Mikuni 172.5 main jet even with the Dynojat needle. Also purchase a Mikuni 37.5 pilot jet to install. Set the needle on either the 4th groove with the spacer and 1 washer under the clip or 3rd groove with the spacer and 2 washers under the clip. (either will work) You can use the washer from on top the clip as the 2nd washer. It's not important for the spring on top the clip to set on it, it will be fine without the washer on top. Then set the PMS screw to 2 turns out from being seated and you will be good to go. That should get you into the 40's mpg on a steady hwy cruise. and high 30's to low 40's if you are easy on the throttle in town riding.

whew glad I don`t have to have that washer on top of the clip.
After much consideration I bought a Baron`s Kit so know I have no DynoJet
parts in there at all...just got tired of trying to tune it with that
needle and Mikuni or DynoJet jets....so
Baron`s needle 4th groove,washer,spacer.
172.5 main, 35 pilot, PMS screw 2 1/2 turns.
Thunder Mfg. Air Cleaner

Hopefully this weekend will get to do my 180 mile loop I like to do
and see where my milage is at. I`ve read differant opinions as far as
using the 35 or the 37.5 pilots.

Good luck with you jetting CNWMAN, all seem to vary a little.

The 37.5 will help with cold starts, off idle hesitation and alot crisper throttle response on the low and mid ranges. It won't effect mpg enough to even notice. Unless your driving habits change due to your new found response.