Carb settings

[Kev L]

Having looked at a few threads tonight where various folk are discussing various adjustments to jetting etc I thought it best to start a fresh one rather than hijack someone else's conversation.
So I have un-baffled Scorpion carbon hi-levels and a K&N filter waiting to be installed. I have just re-built my spare set of carbs with a Factory Pro 1.1 Ti jet kit. They suggest stepping up 2 jet sizes for the filter and 178, 175 for D&D or like pipes.
I have fitted 180 & 178(nearest to 177 I had) and the needles are clipped on the fourth down. Does there need to be any adjustment for the A&L motorsport stacks?
Anything else that shoul be taken into consideration, apart from me being hung like a donkey?

[VTRDark]

Where you do see the difference with the stacks is when carb syncing. Both needles rise together with a rev at the same time, where as with a long and short stack, they rise unequal. Either way at idle they should be equal. Not sure about the jetting for the 2 longs. I would have thought needle clip position is more relevant here as the two long stacks mainly effects the midrange.

The beauty of the FP kit is that they use standard Keihin jet sizes so if you want a 177 you could get one and put that in there. But there are so many things to take into consideration with these carbs and every bike is gonna be slightly different according to climate, mods, wear and tear etc. You might find that 180F/182R mains work better for you, it's trial and error without the Dyno. Be prepared to take the carbs off maybe a dozen times before it's perfect What size pilots are you going to start with?

(:-})

[lloydie]

With the dyno jet kit and k&n
A&l stacks I tried many different needle clips positions .
I found it worked best at 4th clip with a washer underneath .
It just wouldn't pull cleanly in any other position .
It's all about trial and error .
I've had my carbs off about 20 times trying to get it to run good .
And now it is
I also found 48s slow jets helped a lot when setting mine up

[Stephan]

If you will stuck with the hole in midrange when adjusting, try to plug one slide hole in front, and put back original paper filter - biggest difference of this kit to Dynojet is that needle slide speed is unchanged - doesn´t work with cotton filter (BMS in my case).
Don´t use their 50 pilot jets, it´s too much. 48 is fine.

[seb421]

I keep wanting to get my carbs done to suit my pipercross and yoshi's but I just don't have a clue with them, think I'm just gona take it Blackburn Rocket Centre as it's the approved dynojet place near me, wombles knows how much it's going to cost?

Sent from my HTC Desire HD A9191 using Tapatalk 2

[tony.mon]

I keep wanting to get my carbs done to suit my pipercross and yoshi's but I just don't have a clue with them, think I'm just gona take it Blackburn Rocket Centre as it's the approved dynojet place near me, wombles knows how much it's going to cost?

Sent from my HTC Desire HD A9191 using Tapatalk 2

Unless you have a lot of time on your hands and enjoy pulling carbs off and putting them back, what you suggest is by far the easiest solution.

If you costed your time it would also be cheaper.

[VTRDark]

Unless you have a lot of time on your hands and enjoy pulling carbs off and putting them back, what you suggest is by far the easiest solution.

Yep, I totally agree with that.

If you costed your time it would also be cheaper.

Unless your one of those people that like to tinker and change/test things (like your young self Tony ) then buy a Flow Commander and a Wideband A/F Gauge. And then one can save on so many carb strip downs and Dyno time.

Have Fun.

(:-})

[seb421]

Looked at those flow commanders and silimar things they look good think mik has one fitted?

Sent from the Millennium Falcon via Carrier Pigeon

[VTRDark]

He has got one yeh, I've been reading his posts on it. The way I see it, it has two purposes.

1: It allows one to adjust your jetting on the fly, so if your visiting the Highlands your getting into the high altitude zone or any other climate changes like summer/winter, one can adjust the carbs accordingly.

2: It allows one to work out whether they are running too rich or too lean in various areas throughout the rev range. So it makes any jetting changes more accurate and saves time stripping the carbs out all the time to work out which way to go with the jetting. The carbs still need to come off for changes but it cuts down on the amount of times. By adjusting the screw in either clockwise or anti clockwise it adjusts either richer or leaner one jet size.

I will have to find mic's post over on the hawk site later and post here as he explains it better than me. I'm still learning learning learning learning It's never ending.

If I had the money I would get one, but for now I shall have to set my carbs up the hard way on the seat of my pants with a bit of guess work/trial and error. Probably not a bad thing as it will teach me loads.

Have fun.

(:-})

[lloydie]

A New Addition Many have been asking if the Flo-Commander will work with the pilot circuit as well as it does with the main circuit, and do we have the parts to fabricate a set-up for it as well. Well, the answer now is yes to both questions. This arrangement enhances operation at idle as well as throttle response from a closed, or a slightly open position. Many times as you close the throttle upon entering a corner, then start to crack open the throttle there is a lag then a sudden hit of power, (which has been the cause of more high-sides than many racers want to remember). This is evident/noticeable on race engines where this area (from closed to 1/16th or 1/8th open throttle) ), has been given little tuning time, or just can't be tuned well using normal methods, due to many different reasons. This is common with many Flat-Slide type set-ups, as well as stock carbs which are many times very lean at idle, and at a "just cracked open position". With the stock set-ups, the problem is not usually enough of a problem to be noticeable or to be concerned with. The idle mixture screws will usually take care of a lot of that area. However , the Flo-Commander system set up with this circuit enhances throttle response from the closed throttle & "just cracked open position", and increases power thru better synchronization. Due to the fact that with most o.e.m carbs, the pilot circuit uses fairly large air restrictions, and the fact that at part throttle, precise synchronization really makes a difference. As your throttle position opens further, into the main circuit, your other Flo-Commander will take care of the mixture and synchronization from there to W.O.T. or red line. On a street Sportbike, when you are cruising at a lower part throttle position, say up to 3500 or so, the Flo-Commander set up on the pilot system will solve many tuning problems, which make the engine run rough or surge there. Again, our system on the main circuit is the best for overall improvement, but if need be, a set-up on the pilot system can be a great plus as well.
Reply
mikstr 02:02 PM 06-25-2009

[lloydie]

Here is the write-up on how the Flo-Commander works:

General Technical Information
When most any carburetor is being designed the first time, one of the most complicated areas to make work correctly is the transitional areas, where the carbs are trying to deliver a smooth power/ fuel curve area as the rpm`s go from the pilot to the mid circuit, then the mid to the main or top end circuit. This is where most of the stumbling and dead spots occur that make the power drop or be erratic. The other big issue is keeping the carbs synchronized after you leave the idle area and bring the rpm up, (ever watch your synchronization gauge after bring up the rpm`s, even after having them all even at idle?)
Also air moving around in the air box, gives different pressures to each of the four carbs , causing them to run way out of synchronization, resulting in inconsistent, uneven, erratic power.
The Flo-Commander takes all fuel air circuits, from the MAIN AIR JET LOCATION, (via our tubing adapters, and tubing), and routes them all into one location, so that each carb gets exactly the same amount of air all the time. The result is much smoother transition areas I previously talked about as well as all other areas being enhanced as well. The icing on the cake is being able to adjust the amount of air you are letting into the system, thus you can meter the air/fuel mixture, from one location, without doing anything to the carbs. And the system can even be installed without having to go into or removing the carbs at all, under normal circumstances.


The Flo-Commander ties/blends each of the carburetor's fuel to air mixtures to one, Thus eliminating the results of uneven air pressures around the carb air jets causing the multiple fuel/air mixtures of the diff. carbs to thus be much better synchronized through-out the entire RPM range (approx. 3000 to red-line or 1/16 - 1/8 throttle position to W.O.T.) instead of just at idle. You adjust the fuel/air mixture of all the carbs at once by adjusting the thumbscrew to add or limit the air going into the main circuit. The carbs in which we remove the main air-jet to install the tubing adapter have a carefully sized and shaped restriction inside the tubing adapter. We use this, and use the same restrictions already in place (on the carbs we just press the adapter down over the air-jet), to ensure that even if the flo-com. adjustment is opened way up it won't be dangerously lean. When opening it all the way, it does allow a certain amount more air through (to go slightly leaner in the mixture) because even though the restriction is the same size, the other effects such as air velocity & flow, in the tubing, allow / enable it. You then have a more broad range of adjustment.
The first sought after, and now acquired goal, is smoother circuit-to-circuit transition areas, as well as much better synchronization. The next sought after and acquired goal is being able to adjust (to a certain degree) multiple carburetors from one point.
End result; more TQ & HP, a more smooth and predictable power curve, convenience of tuning, the flo-c. will aid in determining where your jet size should be, if you make radical engine mods, while allowing the finer adjusting to be done with the unit itself. How much power you gain will vary , but, we have seen averages of 2 or 3 in a few areas, up to 10 or 12 and higher in others. An over all average gain in a particular situation, as long as the installer of the Flo-Commander at least average skills as far as a conscientious mechanic, and (DEPENDING ON WHAT WORK HAS ALREADY BEEN DONE & HOW CORRECTLY IT WAS DONE) has been somewhere between 4 & 6 hp , and so importantly a MUCH SMOOTHER application of that power.

Jet Kit info
This is covered in the instructions that come with your F.C. system as well.
If have installed a “Dyno-Jet” Jet Kit, you may have a plug or restrictor in the main air passage. This is a list we have compiled so you will have an idea if you will need to remove a plug or restrictor so the passage can be used to it’s original flow potential again. You will be able to set up the Flo-Commander w/no problem, no matter what jet kit brand or type you may have installed. The list here is handy, as it will tell you if you should purchase our handy super time saver Plug/Restrictor Removal system. You can remove them without the system, but the few bucks for the system is well worth it even if you only ever use it once. They are just a convenience we offer to you. If you have another brand/type Jet Kit, the passage is most likely not plugged or restricted. As a “rule of thumb” if you are removing a restrictor, and the jetting was “Right On”, you can go up just one size on the main jets, to bring the mixture back into a neutral position, and fine tune with the F.C. If you remove a plug, you can go up 1 or 2 sizes with the mains and fine tune with the F.C. These are basic settings/suggestions. You could make up the difference with just the F.C., but because you would be closing it substantially to get the mixture back rich enough, you wouldn’t be getting as much of a synchronization effect, as you would not be allowing the circuit to be utilized as much.
Many times though we have found that the Jet system installer, did not put the plugs or restrictors in anyway, in which case it’s an extra easy install.

Corrector/Restrictor mean the same thing below.
VTR 1000 97 – 03 stage 1 n/a

[Kev L]

Interesting reading thanks guys. I fitted the #50 pilots, so I take it I need to step down to the #48's. I am intending to take a run to a Dyno at some point in the near future.
By the way Carl nice sketch mate.

[VTRDark]

I am so tempted to buy one.....I Must Resist...I Must Resist....I Must Resist.... for a month or so anyway.

Thanks Lloydi, the more I read the more it's tempting me.

Here's a quote from mic. Reading this is what got me all started on it.

I have been running one for a few years now and in many ways felt the way you do. This is not to say I felt no effect, but suffice to say I found it to be somewhat subtle. A tuning experiment two weeks ago, however, exposed me to a new dimension of "effectiveness" I didn't think it had.

I had just finished making an airbox mod to my VTR (added a second 4.5mm "shim" under the air filter). When I rode off, with the F-C set at 2.5 turns out, the bike ran like crap, a significant lag in response and surging at steady throttle. Less than 5 minutes after leaving the house, I was about to return home and "undo" what had taken me a few hours to complete when I thought I'd give the F-C a try (besides, what did I have to lose?). Three "fine tuning" stops later, I settled on the screw set at 1/2 turn out, the bike now a revelation (and blast to ride!). Response was instant, surging was gone, and bike pulled harder than before the mod. I now have a newfound respect for the device as it saved me from at least one or two tank removal-airbox removal-carb removal,.... sessions; two turns of a screw took me from despair to elation in a few short minutes, all thanks to the jetting adjustment range (I didn't think it had). Now, it must be said that I happened to test it in its most effective adjustment range area, the screw becoming ever-more effective (and sensitive) as it closes...

Taken from http://www.superhawkforum.com/forums/mo ... ent-28454/

Have Fun.

(:-})

[VTRDark]

I fitted the #50 pilots, so I take it I need to step down to the #48's.

I think that would be better. IIRC As long as the A/F screw is more than 1 turn out and no more than 3. 48's I think are a good starting point. By putting a larger pilot in, increases the fuel so less turns on the A/F screw. Smaller pilot increases the turns. So it's a case of finding a balance. I think Benny had 50's in his at one point but ended up going back to 48's. I remember reading that somewhere.

(:-})

[Kev L]

Cheers Carl. By the way before you spend out on the ign advancer Benny was saying he was trying to get some made up.