I have an '06 Roadie 1700.
Vance & Hines long Shots w/ baffles loaded
K&N air filter
Ported & surfaced manifold
Stock Mikuni Carb
#40 Mikuni pilot jet
#175 Main jet
Stock needle (would love to find a suitable adjustable one)
I ride in South Florida (Sea Level? or close to it?)

I'd like to improve my A.F.R. for better mileage.

Did a little "treasure hunting" thru a
H.D. Mechanic's jet organizer and found
a #32.5 Pilot jet and a #165 Main

Just wondering if these could work
or if they are too small.

You fellas here are a wealth of good advice,
so I wondered what the Great Gurus thought.

Thanks Guys &
Happy New Year,

Spydr

If you are using a stock needle you are already running lean on the main jet. I would recommend buying a jet kit and follow the procedure to jet it properly. I have never heard of anyone using a pilot jet smaller than a #35 in a stock carb. What MPG are you getting now? and what type of riding? Hwy or in town?

The 32.5 would be a tad lean, then again, there is a way too. Just depends on how much time and or money if you want to pay the price for AFR runs.

There was an article I read that went into some depth on the pilot ckt, basically, and I'll try to keep it short and easy. LOL
the pilot jet has 4 holes, 1 is metered by the pilot screw the other 3 are not. This is what sets up the idle (the metered hole), then just off idle, the other 3 kick in plus the metered one. What the article said was that if you changed the pilot a full size (not half sizes), then in order to get the same AFR at idle, you would turn the pilot screw by approx 1.5 turns. So if ya went leaner on pilot jet, then the pilot screw would need to be 1.5 turns richer. Your cruise mpg, as per Mikuni is tested at 65mph on a straight as calm a day as possible. Cruise is determined by the amount of fuel from the pilot ckt and the needle and the needle jet. The portion of the needle that is considered the cruise range is the diameter of the needle just before the taper. It is small of an area that is considered the cruise portion of the needle while it rides up and down in the needle jet. A lot of people don't realize that getting heavy handed on the throttle eats a lot of fuel since then you are getting quite a bit from the main jet, and the needle is rising way past the point of the cruise section. Yrs ago, myself and one other decided to experiment with mains and how little they effect mpg at cruise. I went to a 190 mikuni since that was the largest I had, he put in a 205, we both used a 167.5 normally. If we stayed slow at take off, and not getting heavy handed at all, neither one of us saw more than a 2 mpg difference at cruise.

Any way, I have read quite a bit of info on carbs over the past 6yrs, read about various issues that others have had and what the outcome of fixes were, but I do not know one person that went smaller than stock pilot (35) and only a handful that went larger due to certain circumstances, which mainly were air kit and not using the Barons or DJ needle. These two needles are almost identical in taper, but the DJ is shorter by the thickness of 1 washer.

any way, use what ya can, toss the rest

davej wrote:
What MPG are you getting now? and what type of riding? Hwy or in town?

40-42 MPG Hwy @ 70 ish.

So if ya went leaner on pilot jet, then the pilot screw would need to be 1.5 turns richer.

So Erbman, are you saying that if I go 1/2 a size below stock,
that 3/4 turn or so out on the PMS should get the mix close to
where I want to be?

According to what Erbman said you would have to go 2 1/4 turns richer than where you are at now with the #40. You need an adjustable needle set on about the 4th groove and your current jetting will work. But IMO your main is still a little small for maximum performance.

davej wrote:
According to what Erbman said you would have to go 2 1/4 turns richer than where you are at now with the #40. You need an adjustable needle set on about the 4th groove and your current jetting will work. But IMO your main is still a little small for maximum performance.

Not looking to race a 700lb motorcycle dave.
I'll trade some of the 125 mph for the best use of my 3.00 plus a gallon.
I'd also 'rather not' buy an entire jet kit just to get a needle.
If that's what I must do then o.k.

It's just that there are folks here who have attained 50 MPG (hwy)
and that's what I'd like to approach. 40 around town would be good too.

The Oil Kings don't any more of my 'Chump Change' than I absolutely Have to give them.

Sorry about the tirade man, but gas prices are getting more ridiculous every day.

You can obtain both performance and MPG if you are properly jetted I get mid to upper 40's MPG at 65-70 MPH and I'm pushing just over 75HP and 100 Tq. and that is because it is properly jetted. My jetting isn't much different than yours( check my profile). But you do need the adjustable needle. I agree that I wouldn't want to buy a jet kit just for the needle and maybe a couple $2 jets but without the needle you will not get it done. Maybe someone here has a extra needle in their spare parts box. BTW max performance dosn't mean racing a 700 bike It is just the results of doing the job correctly. And Part of the results is a good MPG.

Thanks Dave, I appreciate your help and advice.

Again, sorry for the tirade.
More so now that I see that I misunderstood
your meaning

Happy New Year,
Spydr

Word of warning to you if you go smaller on the pilot you will have to go out more on the PMS. At 4 turns out you stand a VERY GOOD CHANCE of the PMS vibrating out while riding. I know because mine did a few years back when I still had my OEM CV carbs. I was running a 35 pilot, 172.5 main, Barons needle with the clip on 4 at the time. I finally ended up with a 37.5 pilot, 172.5 main, Barons needle with the clip on 3 with two silver washers and I would get 48 - 52 highway, 36 - 38 city. I had a ported stock manifold Bub Stubbies with torque chambers and a BAK then changed to a K&N RA-077V filter. The bikes put out 75 hp 98 ft lbs tq and I do have a very heavy hand a lot of times. Get it right and you will get good mileage and good performance booth.

davej is right..the whole jet kit works together as a unit.. if you do it right..and i did mine over many times..you will pull around 48mpg give or take..i get that on both our roadstars..do yourself a favor spydr..just go with the whole jet kit ... it will pay for itself in no time..and my bike wont even run on the 35 pilot..the 37.5 works perfect for me.. so now when i get my maxair kit i hope to leave the carb setup as it is..