New jets, question.

[davit]

I recently pulled my carbs and replaced severely clogged slow jets with 38's, and while I was at it the mains with 105's. 

Performance improved 100℅ but milage dropped  10℅ from 30 mpg to 27 mpg.

Initially I had the mixture screws at 1 3/4 turns out, changed to 1 1/2 turns but still smells a little rich.

I have read that 105's may be too large and effect milage, so at some point in time I may change them back to 100's, but I am leaving on a 4500 mile trip in three days so will leave as is for the time being.

So my question is, based solely on decreased milage and smell, is there anything I should be concerned about and look at before heading out?  I plan to ride it like I stole it the whole trip.   

[hukmut]

I like riding fast. Real fast, whenever it is "safe". Like wide open road with slight chance of meeting a "LEO". 
Having said that, I really don't like stopping to buy gasoline. So, if your current jets are using more gas, you are gonna buy more at "ride it like you stole it" speeds.  Now, don't call me a "wet blanket" or "buzz kill", because I DO like to ride fast. I also know that an overly rich mix will carbon up the engine oil. Carbon causes friction. Friction causes wear.
With all this taken into consideration, ride safe.

[Oldnick]

I recently pulled my carbs and replaced severely clogged slow jets with 38's, and while I was at it the mains with 105's. 

Performance improved 100℅ but milage dropped  10℅ from 30 mpg to 27 mpg.

Initially I had the mixture screws at 1 3/4 turns out, changed to 1 1/2 turns but still smells a little rich.

I have read that 105's may be too large and effect milage, so at some point in time I may change them back to 100's, but I am leaving on a 4500 mile trip in three days so will leave as is for the time being.

So my question is, based solely on decreased milage and smell, is there anything I should be concerned about and look at before heading out?  I plan to ride it like I stole it the whole trip.   

I am a bit rusty here, so I am risking a shellacking.......

Ypu are replacing _clogged_ jets and asking questions?

If your perform is 100% better with the new jets at 10% more fuel then WTH?

And I am rusty here, but aren't screws only for idle?

If you "plan to ride like you own the trip" then your fuel use and skin scrape are up to you. Your silly questions make me scared.

Nick

[Patrick]

These monsters run rich, so, with 38s and 105s it'll run richer even with pilots set at 1.5.
Even when new with 35s factory set [ 1.75] if you stick one of these critters in the garage with door closed while running, it won't take long for you to open that door and grab a breath or two.

[GOOSE]

I'VE BEEN RUNNING 38-SLOWS/105 MAINS  ALL SET AT 1 1/2 TURNS OUT FOR YEARS NOW WITH NO PROBLEM. QUIT WORRYING, AND RIDE IT.

[davit]

Thanks guys, I needed some reassurance.

Before replacing the jets I'll bet I spent 200.00 on carb cleaners:  Seafoam, STP, Royal Purple, Berrymans...  what a waste of time and money and extremely frustrating.     45 bucks for some new jets, some time and she's a whole new machine.   





 

[signart]

The 38 slows won't cost any mileage. Don't know about the 105's, but would be suspect.

[John Schmidt]

OK.....everybody that bought their Valkyrie for the gas mileage, please raise your hand.

Hmmmmm....thought so! Neither did I. 

[98valk]

OK.....everybody that bought their Valkyrie for the gas mileage, please raise your hand.

Hmmmmm....thought so! Neither did I. 

that's why a lot of people have sold their valkyries and why sales dropped, the word was out about the bad mpg.
thank's to honda for a terrible ignition system and a bad exhaust system.
they did it right on the goldwing 1500, weighed 900+lbs and still got the same mpg and sometimes better than a valkyrie. the 6 vs 2 carbs have nothing to do with.

[Challenger]

"they did it right on the goldwing 1500, weighed 900+lbs and still got the same mpg and sometimes better than a valkyrie. the 6 vs 2 carbs have nothing to do with."

But I'll bet the extra H.P. would have something to do with it!

[98valk]

"they did it right on the goldwing 1500, weighed 900+lbs and still got the same mpg and sometimes better than a valkyrie. the 6 vs 2 carbs have nothing to do with."

But I'll bet the extra H.P. would have something to do with it!

not sure what point your trying to make. the valkyrie has an inefficient ignition system and an exhaust that is not the best for power and mpg.
 HP and mpg do not always go hand in hand. usually weight and aerodynamics are the main factors. An individual runner multi-carburetor system is always more efficient and makes more power than a single carburetor manifold system.

motorcycle consumer news 4/99 test

I/S         94.9 hp 92.8 lbft   wet weight 833lbs  mpg high 32, avg 30.7
GW SE    79.7 hp 91.2 lbft   wet weight 912 lbs  mpg high 33.4, avg 32.2

[Challenger]

My point was, you don't gain 15.2 hp and 1.6 lb ft from virtually the same engine without sacrificing some mileage.  Wasn't meant to upset anyone.

[98valk]

My point was, you don't gain 15.2 hp and 1.6 lb ft from virtually the same engine without sacrificing some mileage.  Wasn't meant to upset anyone.

not true.
I fixed the exhaust system by installing a system with a collector,
partially fixed the ignition system using a dyna and modifying the TW.
net result, more HP/TQ and avg 38-40 mpg, hwy btwn gas stops I've see 50 mpg.
an efficient engine will make more power and MPG. stock my bike avg 32-33 mpg hwy I was lucky to see 40mpg.
the GW has a collector exhaust and a vacuum advance style ignition system, reason it gets the mpg it does while carrying over 100lbs more weight and a good chance not as aerodynamic overall.

[Robert]

I have 110s in the mains its not the mains or the slow jets its the needles that will make the difference in mileage. If you lean the mid range (needles) then your cruise will pick up mileage. But at idle and full on you will increase power lessen mileage and get a smoother idle. But since most of the time you are cruising you will actually increase your average gas mileage. If you smell rich you probably are and I would not leave it there. This is of course saying that the carb is functioning properly and not clogged. A few companies make different needles in the event you cannot correctly adjust the mid range. These bikes do like fuel but at the correct ratios. When I started to play with the jets I actually increased mileage and had more power. On mine I really should go to 115 on the mains but just don't want to take the time since I'm pretty happy with where shes at now. CA is also correct with the advance on the timing if you to a 6 degree trigger wheel it will help mileage also.

[Blackduck]

Slows will affect your mileage along with the adjustment on the mixture screws.
These spend most of their time using them.
Have tried 38's and too rich on the dyno.
Mixtures were at 1 3/4 and still smelt rich at idle, closed them 1/4 turn and tried it. Still ricj=h smelling and no change to idle, dropped another 1/4 turn. Smells better, had to lift the idle a touch and gained a couple of MPG on my usual runs. Nothing else changed.
On needles tried after market but too rich, back to stock 97 needles as they are a tad richer than the later ones.
NOTE, my airbox is well played with and running 127.5/130 mains (not sure without looking at my records)
35-38 MPG riding as I like, very little variation with speed, unlike stock set ups that love sucking fuel above 3000 RPM

[Chrisj CMA]

Rich is better than lean,  If you have a stock air filter, going to a K&N will lean it out some

[98valk]

I have 110s in the mains its not the mains or the slow jets its the needles that will make the difference in mileage. If you lean the mid range (needles) then your cruise will pick up mileage. But at idle and full on you will increase power lessen mileage and get a smoother idle. But since most of the time you are cruising you will actually increase your average gas mileage. If you smell rich you probably are and I would not leave it there. This is of course saying that the carb is functioning properly and not clogged. A few companies make different needles in the event you cannot correctly adjust the mid range. These bikes do like fuel but at the correct ratios. When I started to play with the jets I actually increased mileage and had more power. On mine I really should go to 115 on the mains but just don't want to take the time since I'm pretty happy with where shes at now. CA is also correct with the advance on the timing if you to a 6 degree trigger wheel it will help mileage also.

cruise speed will be strictly the PJs if they are sized and tuned correctly. cruise should never be on the needles. cruise should only be 1/8 to max 1/4 throttle, anymore than that and we're into the needle circuit which means lower mpg.

[Robert]

I have 110s in the mains its not the mains or the slow jets its the needles that will make the difference in mileage. If you lean the mid range (needles) then your cruise will pick up mileage. But at idle and full on you will increase power lessen mileage and get a smoother idle. But since most of the time you are cruising you will actually increase your average gas mileage. If you smell rich you probably are and I would not leave it there. This is of course saying that the carb is functioning properly and not clogged. A few companies make different needles in the event you cannot correctly adjust the mid range. These bikes do like fuel but at the correct ratios. When I started to play with the jets I actually increased mileage and had more power. On mine I really should go to 115 on the mains but just don't want to take the time since I'm pretty happy with where shes at now. CA is also correct with the advance on the timing if you to a 6 degree trigger wheel it will help mileage also.

cruise speed will be strictly the PJs if they are sized and tuned correctly. cruise should never be on the needles. cruise should only be 1/8 to max 1/4 throttle, anymore than that and we're into the needle circuit which means lower mpg.

I don't know if we are talking about the same thing, I am referring to the needles in the slide. They are the ones that control off idle to 3/4 throttle. You do have emulsion tubes in the carb but these are the main jets you use. Throttle opening is really not a point here since these slide needles handle almost everything above idle. Idle is the idle jets, mains are the one that come into play when the needles are almost all the way out of the hole they fit into. If you doubt just move the clip in the needle one richer and go for a cruise and watch your plugs.

[98valk]

needles control 1/4-3/4 throttle
at idle to 1/4 throttle there isn't enough velocity thru the carb to draw fuel up thru the needle/mj well.
going down the hwy 1/8 throttle if PJ is set right needle circuit does not come into play.
needles too rich then yes black plugs from when the needles come into play during acceleration aka the midrange, not during idle and/or 1/8 throttle.
tape along side the throttle and mark throttle positions, then go for a ride, it will be seen how little throttle is actually used during hwy cruise.

0-1/8-1/4 throttle are the pilot jets. this is why I've written many times that stock PJ are all that are needed if no air inlet and exhaust mods are done. the mixture screw just needs to be opened up up to 4 - 4 1/2 turns open before the next larger PJ is needed. I have major air box mods with Viking exhaust and 38 PJs are what are needed, next size 40s were too large.
every one who has a stock bike and puts in 38s and then has to turn the idle mixture screws to  1 1/2 turns open tell me the PJ are too large. using the stock PJ and opening up the mixture screws to 3- 3 1/2 would provide much better performance, throttle response and MPG.


PJ overlaps all fuel circuits and even affects small throttle movements at 3/4-WOT when the MJ is be used.  needles are not in use.
PJ, needles and MJ all overlap for smooth transition.

[Paladin528]

while not specific to the Valkyrie carb this is how the system is layed out in a standard CV Carb.

http://s54.photobucket.com/user/sgozdzi/media/tuningparts.jpg.html

[Robert]

That chart does really describe the correct way the carbs work.

   If you use the idle jets to control part throttle you will not get the right mixture or balance through the whole range. A real problem when you idle and foul plugs or have a rich mix smell at idle.  Actually the idle circuit needs a high vacuum to work. So when the air is drawn into the front through the slide as the slide raises it keeps the vacuum consistent at the base of the slide needle through the range and gas is drawn up through the slide needle seat. That is why its a variable venturi carburetor. Vacuum to the idle jets is less and less off throttle closed position. There is no way to keep a consistent fuel mixture if the vacuum is less and less. They use the idle circuit as a enriching circuit for a smooth transition to the slide needle taking over at anything above idle. But it only needs to be rich enough to keep that transition smooth and good idle and why at anything at cruising speed you can lean the carbs out to get max fuel mileage or max performance. In this mid range as long as you have the top and bottom end of the engine ranges covered you will more than likely never feel it. Its this that will give you the top fuel mileage you can get since at 2000 to 3500 its the slide needles that get the most play and where the engine will see most of its life. This is well beyond 1/8th throttle as measured at the carbs not at the grip.

This below is a direct post from the article that explains a bit better what I am saying

http://www.vulcangadgets.com/files/keihin_carb.html


                 PILOT SYSTEM - Steering You to Better Lows


The primary purpose of the pilot system is to supply the mixture at idle. It continues to supply fuel throughout the entire throttle range, but after about 1/8 throttle is reached the MAIN SYSTEM starts to put out an increasing percentage of the total mixture up to full throttle.

[98valk]

www.factorypro.com
top of page click "support"
then click "Tunning Tech"
then left hand column "CV carb tunning"
then "low rpm engines"

CV Carb Tuning

for Lower rpm engines

[Robert]

www.factorypro.com
top of page click "support"
then click "Tunning Tech"
then left hand column "CV carb tunning"
then "low rpm engines"

CV Carb Tuning

for Lower rpm engines

http://www.factorypro.com/tech/tech_tuning_procedures/carbtun.html

Ok found it and  if you look it says start from the mains, then the mid then the idle. Idle is not used to correct these ranges, these ranges need to be pretty good then you tune the idle. Idle adjustment is last and more of a fine tune than a major adjustment.
  
Also if you notice it does say slow engines and while ours does not turn at 12k it does not turn at 2000 at cruise either, the top of the range effected by the idle jets.
  
I run Dyno Jets stage 2 kit for the Valkyrie and in that kit they give you 38 idle jets and custom needles and 100 to 115 mains. They must feel that 38 on the idle jet is adequate and adjust the slide needle to compensate for mid range. Otherwise they could have just gone up on the main and the idle jet and left the OEM slide needles.

  I also have an exhaust gas analyzer to tell the mixture. What I found is the idle mixture screws to be properly set need to be at 1 to 1 1/4 turn. This makes the HC CO perfect at idle, and through the rpm range mine is just about perfect with a slight leaning at the 3 to 4 k range. If I opened them to say 2 turns then my bike was way rich at idle and still rich up to about 2 to 3 k  then everything evened out and the mix was good. If I had tried to extend the Idle jets influence even to an even higher rpm I would have been gassed out at idle and up to 2 to 3k and maybe evened out around 4 to 5k when the mains kicked in. Eventually making the bike unusable at anything below highway speeds. So with this 38 is max on the idle jets and compensate on the slide needles and mains to get the best running out of the bike. Anything that goes outside this is pretty much indicating that there is a problem in one or more circuit.

  I will say this that the Cobra jet kit that only offers a slide needle and no other jets like so many kits is a poor way to get more power and get the best mileage. From what I have seen through my own experience is it makes mid range rich, idle rich and it leans out at full throttle. Further testament to the effected ranges of the slide needles.

[98valk]

www.factorypro.com
top of page click "support"
then click "Tunning Tech"
then left hand column "CV carb tunning"
then "low rpm engines"

CV Carb Tuning

for Lower rpm engines

Ok found it and  if you look it says start from the mains, then the mid then the idle. Idle is not used to correct these ranges, these ranges need to be pretty good then you tune the idle. Idle adjustment is last and more of a fine tune than a major adjustment.
   
Also if you notice it does say slow engines and while ours does not turn at 12k it does not turn at 2000 at cruise either.
 
I run their stage 2 kit for the Valkyrie and in that kit they give you 38 idle jets and custom needles and 100 to 115 mains. They must feel that 38 on the idle jet is adaquate and adjust the slide needle to compenste for midrange. Otherwise they could have just gone up on the main and the idle jet and left the OEM slide needles.

  I also have an exhaust gas analyzer to tell the mixture. The needles do taper differently by a bit. What I found is the idle mixture screws to be properly set need to be at 1 to 1 1/4 turn. This makes the HC CO perfect at idle, and through the rpm range mine is just about perfect with a slight leaning at the 3 to 4 k range.

I have his kit and have talked to Marc a few times. just remember most jetting kits are gear towards more HP, that is what sells. also the kit is based on the dyno work they did on a bike at their location ambient conditions. read his link in that write up for pilot jet adjustment. All I can add if one wants max power and doesn't care about MPG like I do, then follow exactly the kit. My experience some from jetting my Bandit 1200 and Dale walkers kit is geared towards a smaller PJ and opening up the mixture screw to compensate. I used the factorypro kit and Dale's kit for the Bandit, Dales reco's worked much better for mpg, power and ride ability on the street. FP works better for the race track.

[Robert]

Slows will affect your mileage along with the adjustment on the mixture screws.
These spend most of their time using them.
Have tried 38's and too rich on the dyno.
Mixtures were at 1 3/4 and still smelt rich at idle, closed them 1/4 turn and tried it. Still ricj=h smelling and no change to idle, dropped another 1/4 turn. Smells better, had to lift the idle a touch and gained a couple of MPG on my usual runs. Nothing else changed.
On needles tried after market but too rich, back to stock 97 needles as they are a tad richer than the later ones.
NOTE, my airbox is well played with and running 127.5/130 mains (not sure without looking at my records)
35-38 MPG riding as I like, very little variation with speed, unlike stock set ups that love sucking fuel above 3000 RPM

Pretty much my experience also even to the mileage,  I did not go as big on the mains but I was not about to take the the carbs apart again and go bigger. I put in the 115's and it runs good enough and I did take out the baffle on the air filter box. I think you were the one that I looked at the results of and used that as a loose model to change mine around. I did use the Dyno Jet needles and they are good, since I also found the same thing in the aftermarket needles.  So thanks 

[davit]

Six days and 2500 miles into the trip and the bike's running flawlessly averaging 29 miles per gallon at 70+ mph.  Interestingly those numbers don't go down running hard in the mountains. 

[Pappy!]

Davit - That second photo is amazing! Makes this Florida boy want to be there!