Topic: Poor mans jetting kit

[Flying J]

From Cycle X
anybody try this? Thought i might give it a shot on my 550


"This extra gas circuit procedure has been done for years.
Carburetor jetting is an on going topic of discussion.
So, here is what we do from time to time.
Tap into the float bowl and insert pilot jets into the throat of the carburetor.
This procedure will give your bike a boost from  approx 1/4 to full throttle.
Also, it will allow you to check your float level at a glance and purge unwanted sediment from your bowl."

After thinking about it, i dont think its a good idea. Ill stick to the adjustments on the carbs that i know what range they work for.

[cb650]

 "purge unwanted sediment from your bowl"     right into the engine.     

[eideteker]

Call me crazy (or rookie, either works) but 'til you've done all that wouldn't it have been more efficient time- and money-wise to just get a set of bigger jets?  I'm all for bodgery if it's functional, but this seems like a waste.

[Flying J]

Yeah, its like adding another fuel circuit for the sake of adding it. Like tunning carbs isnt complicated enough with the few adjustments we already have.

[buffalogt750]

Nothing new. Lectron has been making power jet carbs for years. Used mostly on two strokes.

[Simpson]

I'd have to say, if the engine had the extra capacity from the start, I think Honda would have incorporated it into the existing carb. I'd have to assume they did some extensive testing with jetting back then.

[Terry in Australia]

Nothing new. Lectron has been making power jet carbs for years. Used mostly on two strokes.

Dead right mate, and nothing wrong with it either. There was a lot of stuff that Honda could have done to make our bikes better (oil coolers, twin discs with decent calipers, steering dampers, fork braces, better suspension, better ignitions, etc etc) but that would have made the bikes too expensive in the showroom, so they compromised a lot of things to keep costs down, hence the huge "aftermarket" industry that grew around the CB750 in the 1970's.

The "Power Jet" on lectron carbs works well, and the benefit that I can see straight away is that the little squirt of gas on accelleration will help reduce "throttle lag" when you open the taps. As far as tuning goes, just block off the hose if it's causing you problems, not that i think it will.

"Purge unwanted sediment from the float bowl right into your engine"? Can't see a problem here, it's already passed through your petcock filter and any additional filters that you've installed in line, passed through the fuel valve filters, so providing it'll get through your "power jet", (previously known as the pilot jet) it is so tiny it's measured in microns, so won't hurt your engine, or performance. Cheers, Terry.    

[wannabridin]

so terry,

would you do something like this to your bike?   

my concern would be for float bowl height?  would this affect the height you've set them to and allow the bowls to drain too far leading to a lean condition?  wait, wouldn't the lean condition be counter-acted by the fuel going back into the motor?  hmmm, seems like a bit of an infinite loop resulting in a stock carb condition.  at least to those that aren't carburetor saavy like some of the old timers??

 

[Cormac]

Looks like they are attempting to set this up like the fuel bars on a predator carb. Only problem I see is that the jet isn't "in" a venturi. The predators put theirs just after the venturi plates, basically the same place as the jet on bike carbs anyway. Would there be enough of a pressure drop there to actually draw fuel?

[edbikerii]

The only problem with the carbs on the 77 CB550K (yes, even with the stock airbox) is that when you whack the throttle open quickly, the engine gets too much air, not enough fuel, and stumbles slightly until the fuel flow catches up.  This problem was corrected later when CV carbs became the rule on motorcycles, and the slides would only rise to pass the air that the engine actually could consume.

The CB550s would have enjoyed great benefit from an accelerator pump like that on some of the later 750 carbs.

Ported vacuum is highest when the throttle is initially whacked open, thus pulling more fuel through these jets when needed.  Then the ported vacuum tapers off to equal manifold vacuum.

Seems to me these would actually work pretty well.

[Terry in Australia]

so terry,

would you do something like this to your bike?  

my concern would be for float bowl height?  would this affect the height you've set them to and allow the bowls to drain too far leading to a lean condition?  wait, wouldn't the lean condition be counter-acted by the fuel going back into the motor?  hmmm, seems like a bit of an infinite loop resulting in a stock carb condition.  at least to those that aren't carburetor saavy like some of the old timers??

 

Yeah mate, I've got a few sets of carbs here holding up my workbench, so I'd give it a shot, but I've got "Pumper" carbs on my F2, 29mm CR's on my K1, and I'm not gonna modify my K0's "unobtainium" cable carbs, and that's probably why I haven't done it already. I need to point out that this is common practise on some older dirt bikes (TS Suzuki's for instance) so is not "Snake Oil", it's just (obviously) something that a lot of folks here probably haven't seen before.

The amount of fuel passing through the pilot jets would be minimal (try finding a wire fine enough that will unclog one) and if the OEM fuel petcock will easily keep the fuel up to any carb ever fitted to a CB750, it'll have no problem keeping your float bowls filled. Cheers, Terry.

Looks like they are attempting to set this up like the fuel bars on a predator carb. Only problem I see is that the jet isn't "in" a venturi. The predators put theirs just after the venturi plates, basically the same place as the jet on bike carbs anyway. Would there be enough of a pressure drop there to actually draw fuel?

Put your hand over the back of your carb with the engine running mate, if it was small enough it'd be sucked in one end and spat out the other.  

[scunny]

keep those  rough hands of yours out of the discussion Terry

[Zaipai]

Ok I think if I can get my hands on a set of carbs I will give i a try.. I have seen this setup on other bikes but never asked how it worked. Seems it should work ok..

If I do it and it works I will update this post.. probably wont get to it till later in the spring tho.

.: Scott :.

[Flying J]

I like the idea that it would deliver fuel when i cracked the throttle open fast but i see two problems with that idea.

1) For that jet to deliver fuel it would have to suck it all the way from the float level, through the tube, up to the jet before it spat out any fuel.

2) the actual jets would be at a higher pressure differential and closer to the fuel so they would deliver fuel before that jet ever did.

Just my observation. I think it would work good to richen the mixture over a broad spectrum. For example, instead of raising the needle and changing the main jet you could just add this and accomplish both those task at once.

[edbikerii]

Yeah, fair enough.  I suppose that it is true that the fuel level will settle down in the tubes to the same as the float level, as there won't be constant vacuum at the jets (at idle, for instance).  The thing is, at WOT the vacuum will be pretty low, too.  Enough?  Maybe.  Ported vacuum gauge would tell the whole store.  Personally, I don't care enough to try it.  The slight hesitation is so minor that I think it is irrelevant.

Also, it really isn't that hard to tune the jets the normal way.  So, if it doesn't work like an accelerator pump, then it is a waste of time, in my opinion.

I like the idea that it would deliver fuel when i cracked the throttle open fast but i see two problems with that idea.

1) For that jet to deliver fuel it would have to suck it all the way from the float level, through the tube, up to the jet before it spat out any fuel.

2) the actual jets would be at a higher pressure differential and closer to the fuel so they would deliver fuel before that jet ever did.

Just my observation. I think it would work good to richen the mixture over a broad spectrum. For example, instead of raising the needle and changing the main jet you could just add this and accomplish both those task at once.

[Flying J]

I concur

[TwoTired]

A couple of arm chair comments, no actual experience with doing this.  I'm, just thinking about the physics of the mod.

The force drawing fuel through the added jet is the carb throat vacuum ahead of the main venturi.  It won't be variable with the air speed through the throat, unless the filter media ahead of it generates increased pressure loss with increased air volume passing through it.
It WILL be highly effected by the amount of restriction or pressure drop caused by the air filter media ahead of the jet.

From a physics viewpoint, I don't see the advantage of adding another jet in that location.  Strategically, you could make some fuel metering adjustments without removing the slides or main jet.  But, an added jet in that position is NOT better than having the carb's (slide needle, main air jet, emulsion tube holes, and Main jet size) internal fuel metering corrected/compensated for changes from stock,.  Anyway, that added jet won't see much of a pressure drop across its orifice until the slide is opened a bit.  Then, as it is only about a quarter of an inch away from atmospheric pressure near the carb throat, not much differential is going to be present.  Add an inlet runner and inlet restriction, and this is going to greatly effect how much that added jet flows.  I notice it is ahead of the choke.  So, it won't contribute during choke operation.
Seems like a compensation for carb re-jetting, without actually changing the internal jetting.  Getting the flow to balance right seems just as hard as going inside the carbs, but adding complexity.

It most certainly won't compensate for sudden open throttle wheeze/lean stumble.  Suddenly opening the throttle, presents near atmospheric pressure to all the jet orifices feeding the carb throat, wherever they may be.  Since all the jets flow at a rate related to the pressure differential between jet entry and jet exit, loss of differential causes fuel flow cessation.  This is why an accelerator pump, providing a mechanical push on the fuel rather than relying on air pressure differentials, alleviates sudden throttle opening stumble.

If you're interested...

[Buber]

So, I presume that if my carbs are the CV ones WITH accelerator pump, I have those worries solved..

I'd love to put some magic jet in my carbs to boost performance and reduce the fuel consumption, alas.... physics forbid that.... 

[Markcb750]

I wonder (as a few here have noted) how any significant negative pressure is applied to the jet orifice to allow atmospheric pressure on the gas in the bowl to be pumped through that set up. 

The other jets are within the venturi, an area of lower pressure due to the  acceleration/higher velocity of the air molecules. Additionally the existing venturis are on/near the surface of the venturi, where the highest negative pressure is. This jet appears to be at an area of the carburetors that I would expect little or no pressure drop, just air moving past the orifice.


As TT states the physics don't tell me this is a better method then re-jetting.


I do not see any problem with debris as the stand pipe for the drain tubes are in the top of the bowls, generaly above the fuel level.  This makes me wonder if the floats will need to be set higher to keep the tubes wet, or are the tubes shortened?  Lots of issues here including fuel running out the body of the carburetor because the drains are not functional. 

[wannabridin]

Mark,

you make a good point about the lack of a drain, because there's no simple way of getting it to drain without unplugging the hose to the inlet body.

TT,

with an increase in runner length, I would think that the pressure drops relative to atmospheric would be greater at the jets location in the inlet body.  what about if velocity stacks were added?  These increase the air speed due to their design, which would slightly aid in the ability of the jets to draw in more fuel, albeit is probably negligible.

My only concern with the set up is the fact that a high enough vacuum cannot be drawn that close to the inlet that will atomize the fuel well enough to cause a beneficial burn to the a/f mix.  it seems to me that even with a small idle jet that you would be nearly dripping small droplets or streams of fuel into the carbs, which would just burn slowly, even possibly retarding the flame because of wetting on the piston.  i don't know enough about carb operation and tuning to have any merit to my statements, just my ignorant thinking of the subject.

[Zaipai]

Well from what I get from this thread is that it probably wont work. That said, why would Cyclex claim it does, or do they.. Seems like they do. Are they looking for more sales of the parts needed to do this? Also seems like bigger jets would do the same thing, and wouldn't the motor just run richer with out really any gain to power?

I am confused at this point..

.: Scott :.

[edbikerii]

Again, we would do well to place a vacuum gauge at that location to know with any certainty what that jet is doing.

[edbikerii]

Perhaps cycle-x can show us (or actual potential buyers) the vacuum readings at that point in the intake at various throttle openings and rpm.

I'm not from Missouri, but I'd need them to "show me" before I laid out any cash for that mod.

Well from what I get from this thread is that it probably wont work. That said, why would Cyclex claim it does, or do they.. Seems like they do. Are they looking for more sales of the parts needed to do this? Also seems like bigger jets would do the same thing, and wouldn't the motor just run richer with out really any gain to power?

I am confused at this point..

.: Scott :.

[Markcb750]

Perhaps cycle-x can show us (or actual potential buyers) the vacuum readings at that point in the intake at various throttle openings and rpm.

I'm not from Missouri, but I'd need them to "show me" before I laid out any cash for that mod.

Well from what I get from this thread is that it probably wont work. That said, why would Cyclex claim it does, or do they.. Seems like they do. Are they looking for more sales of the parts needed to do this? Also seems like bigger jets would do the same thing, and wouldn't the motor just run richer with out really any gain to power?

I am confused at this point..

.: Scott :.

Attach a gauge to the drain connection point, and one to the set up port...Cycle x should be able to do that in just a few minutes.

Is that motor painted gold or is it anodized?  Just curious.

[Simpson]

As TT states the physics don't tell me this is a better method then re-jetting.

Not to beat a dead horse
+1 changing the main jet seems to accomplish the same outcome
I have confidence Honda sized it correctly.

[Zaipai]

Interesting I could not find a video of this bike in action.. That would surly put things to rest.. no?

oh yea the motor looks painted to me.. but then I could be wrong on that.

.: Scott :.

[bucky katt]

i was looking through the cyclex site this morning and i have to wonder, what would happen if the jet were screwed into the hole where the carb synchronizer tubes would mount? just my curiousity getting the better of me.

[le_sterls]

Interesting enough of a thread... Would never do such a thing to my bike, IMHO. Are those cylinders in the picture really lime green/ yellow?

[scroggins5000]

Anyone with a spare set of carbs lying around that also has some money/ time to burn should try this out and let us all know the outcome. 

[eurban]

This type of product has been around a long while.  I'm surprised no one has mentioned "Dial-a-jet"  Its is similar to what cyclex is showing except it offers an adjustable auxiliary jet rather than a fixed size pilot.  Check out this link:   http://www.thunderproducts.com/dial_a_jet.htm
I have no experience with this product but I would imagine that an adjustable unit would make it more useful.  They also seem to have an updated product that allows adjustment from the handle bars. . . . . .

OK, here's their tech article on the product.  Hope they don't mind me pasting it here.  Thoughts??



 Dial-A-Jet Tech Article
Automatic Fuel Induction System

Dial-A-Jet is a completely external jetting system that delivers maximum horsepower from any engine at any temperature or altitude. "DJ" improves throttle response and fuel mileage. It works well with stock or modified engines, standard or high performance air boxes and exhaust systems. Easy to install kits are available for snowmobiles, ATV's, dirt bikes, motorcycles and automobiles.

The Dial-A-Jet system was invented by Dennis Dean, Ph.D. (Doctorate in acoustics). Mr. Dean held over 120 world motorcycle drag racing records and several Bonneville records. The Dial-A-Jet concept was used on all of these machines. He knew that he needed a different fuel curve for the launch area, middle of the track and the end of the track. He also had to deal with different altitudes, temperatures, and air densities. Dial-A-Jet proved to take care of these problems as well as providing that fine tuning edge that meant the difference between winning and losing at this highly competitive level.

Modern motorcycle engines come from the factory jetted on the lean side, leaving little room for error. Motorcyclists often discard their standard air filter and install a high flow air filter. This will upset the air to fuel ratio making the engine run even leaner and hotter. Custom exhaust systems are usually lower restriction which also causes the engine to run leaner and hotter. The combination of the high flow air filter and the low restriction exhaust system substantially alters fuel flow requirements, leaning the engine and raising the operating temperature. The additional heat that is generated can have a detrimental effect on engine longevity as well as delivering poor performance. Gear selection may become more difficult due to increase in oil operating temperature. The cure for these lean conditions is to restore proper air/fuel ratios. This can be done by rejetting which requires removal and disassembly of your carburetors. This may be a very expensive proposition, paying for 3 or 4 hours of shop time as well as purchasing a jet kit. Dial-A-Jet kits can usually be installed at home in approximately 1 to 1 1/2 hours without having to remove and disassemble your carburetors. Dial-A-Jet now allows you to richen or lean your engine in seconds simply by turning a dial. The ability to adjust your carburetors externally may save you another trip to the local dealer to adjust your carburetors if they didn't get it right on the first try.

Lonn Peterson became interested in using Dial-A-Jets on snowmobiles in the winter of 1989/90. Lonn recognized a great need for this product in the snowmobile industry. Large altitude and temperature changes had to be dealt with, not to mention engine modifications requiring attention to the fuel system. They worked so well and the feed back was so positive that he decided to buy the company. Lonn and his wife, Ann, now own Dial-A-Jet which is part of Thunder Products, Inc.

The basic concept of the Dial-A-Jet has never changed since day one; however, it is a highly evolved product that has seen many improvements. Performance has always been the number one consideration. Most other improvements have to do with making the Dial-A-Jet more user friendly, such as fitting into tight places or mounting in easy to access areas, filtering the air to the Dial-A-Jet, reading the settings, etc.

Dial-A-Jet is a very reliable fail proof product that works every time! Dial-A-Jet makes more horsepower on less fuel. You can expect gains in the 3% to 5% range. It's much more than a quick and easy way to change main jets. There are no moving parts or electronics to fail. Dial-A-Jet is a small product measuring only 7/8" long, 5/8" wide and 5/8" high. Air enters the Dial-A-Jet body through one of the five pre-selected air correction circuits in the rotary dial. Each of the five air correction circuits is a different size allowing either more or less air to enter the mixing chamber. More air would be leaner (larger hole) and less air would be richer (smaller hole). Fuel from the float bowl is instantly drawn into the mixing chamber and swirled with air at a high rate of speed emulsifying the fuel. The fuel mixture is like millions of tiny thick skinned balloons with air inside. This is called an emulsified fuel charge. The emulsified fuel charge is inducted into the carburetor through the secondary main jets located in the fuel delivery tube. At this point the Dial-A-Jet is way ahead of the rest of your carburetor. All of the other circuits in your carburetor introduce raw liquid fuel into the air stream, just beginning the atomization process. The lightweight fuel mixture from the Dial-A-Jet only weighs 10% of what liquid fuel weighs. Slight changes in engine load can be quickly and accurately compensated for with this lightweight fuel mixture. Instead of losing as much as 15% of your horsepower due to improper jetting, your machine can now perform at optimum level at any temperature or altitude. A snowmobile will always run like it does at 20 degrees below zero.

Three things trigger Dial-A-Jet's fuel signal: 1) engine pressure drop (vacuum or fuel signal); 2) acoustic sound signal which either amplifies or de-amplifies the reversionary pulse waves of the intake tract (we will explain more about the acoustics later); and 3) air flow and velocity. Dial-A-Jet works from just above an idle all the way to full throttle. Dial-A-Jet automatically gives you a perfectly calibrated carburetor that feeds fuel linear to engine load. Feeding fuel linear to engine load means being jetted properly whether you are pulling a heavy engine load like a hard hole shot with good traction or just cruising easily on hard pack at 40mph. Various speeds and engine loads require changes in your fuel curve. Dial-A-Jet automatically monitors your engine's needs then alters your fuel curve to match. A load must be placed on the engine for Dial-A-Jet to function. You can't rev your engine up on the jackstand and watch fuel go up the lines. Without loading the engine, there is no need for extra fuel; therefore, Dial-A-Jet does not deliver fuel. This is normal.

Dial-A-Jet is an add fuel only device. You cannot add fuel to an engine that is running rich or has an adequate fuel supply and hope to gain horsepower. You must create a lean condition so that Dial-A-Jet has a window of opportunity to function. Dial-A-Jet will automatically fill in the lean areas of the fuel curve giving you optimum performance. The fine emulsified fuel charge can't displace the heavier poorly atomized fuel from the other circuits so it takes the path of least resistance and fills in the lean mix areas eliminating fuel spiking and giving you a consistent fuel flow pattern producing stable temperatures and horsepower. The only way Dial-A-Jet can fail to perform is if you do not get the carburetor within range of the Dial-A-Jet. This usually means that the main jet is too large. You must create a slightly lean condition so the Dial-A-Jet has a working range. This is typically about three or four jet sizes below a properly jetted machine. A single Dial-A-Jet will deliver 10% to 15% of your overall fuel curve in an emulsified state. There are five automatic fuel ranges you can select from on each Dial-A-Jet. Simply rotate the dial to raise or lower your fuel curve. With Dial-A-Jet each carburetor can be adjusted independently. This is a huge advantage for maximizing the full potential of each cylinder while giving you great protection against burn down.

Dial-A-Jet is an acoustical device that is triggered by acoustic sound signals. The acoustic signal is generated when gasoline is ignited in the cylinder just inches away from the Dial-A-Jet. This signal amplifies the pumping action created by the reversionary pulse waves that occur naturally in any engine's intake tract. The acoustic signal along with normal engine vacuum or fuel signal causes fuel to be delivered to the engine. We have all heard the sound of a fat, over-jetted engine such as you hear at high altitude or very warm weather riding. It's the whaaa whaaa sound. This is a slow, fuel rich reversionary pulse wave in the intake tract. This would give Dial-A-Jet a de-amplified fuel signal resulting in little or no fuel being inducted. The reverse of this is also true. A crisp lean sounding engine generates a fast sharp reversionary pulse wave, triggering Dial-A-Jet to automatically induct fuel. Detonation is an extreme lean condition that generates a sharp reversionary pulse wave. This excites the Dial-A-Jet causing a rapid response with additional fuel delivery to stave off engine damage. Remember that we are moving a very light weight emulsified fuel charge. This is the reason it is so responsive to the engine's fuel needs over such a broad range.

Dial-A-Jet works great on stock or modified machines giving a realistic 10% to 20% increase in fuel economy or more. Throttle response is extremely fast and smooth. Throttle lag is virtually eliminated. Throttle lag is where the airflow in your carburetor out accelerates your fuel, which finally catches up. Being that the Dial-A-Jet delivers such a lightweight fuel charge, the air can no longer out accelerate the fuel as it once did. The result is major league throttle response! Dial-A-Jet automatically purges your float bowl of alcohol, water, benzenes, or other unwanted sediments that could cause engine damage. Modified or piped machines will have fuel needs that require a higher fuel curve when the pipes and modifications kick in. In other words you need one fuel curve when running below peak and another fuel curve at peak horsepower. This is why a piped machine is so fussy to jet. More horsepower requires more fuel. Dial-A-Jet will automatically raise or lower the fuel curve optimizing performance. Dial-A-Jet feeds fuel based on engine demand. Spark plugs will last longer. The plug color will be lighter and piston wash will be minimal or disappear due to the improved fuel delivery and combustion efficiency.

Now that we have talked about Dial-A-Jet having so much automatic circuitry, you need to know how the manually adjusted dial fits into the picture. Each of the five positions represents a higher or lower fuel curve (richer or leaner). It's not a case of starting and stopping from one position to the next. There is a great deal of overlap with each setting. For the most part you will seldom need to adjust the dial. A big change in altitude or temperature will be about the only time a change will be necessary. Dial-A-Jet comes with a very easy to understand installation and tuning manual that explains in detail how and when you may need to change settings.

The Dually Kit consists of two Dial-A-Jets per carburetor. It delivers 20% to 30% of your overall fuel needs. This kit was designed to service engines that have high cubic feet per minute of airflow. Highly modified engines or large displacement engines usually fall into this category. Another circumstance where a Dually Kit is used is for extreme temperature and/or altitude changes. You can ride in the Midwest at sea level or you can ride in the western mountain ranges. The Dually provides a very broad tuning range virtually eliminating the need to change jetting. You seldom, if ever, need to adjust the dials due to the high percentage of fuel automatically being metered through the Dually system.

The Snorkel kit is a fitted rubber cap that goes over the Dial-A-Jet body. A vent line is inserted into the rubber cap and routed up the handle bar shaft, exiting just outside of the hood. A foam filter is attached to this end of the vent line. Cold clean air is fed to the Dial-A-Jet. This also eliminates belt dust, snow, ice or other debris from plugging the air correction circuit in the Dial-A-Jet making it run rich. Problems with under hood pressure are eliminated. The snorkel is a must for ATV's and dirt bikes equipped with Dial-A-Jets.

Dial-A-Jet has even been successfully installed on fuel injection machines. One Arctic Cat dealer wanted to run performance pipes on a 580 EFI. The existing fuel map worked fine on the bottom end and midrange; however, the top end was extremely lean. Dial-A-Jets were installed on the throttle bodies. Fuel was pulled from a remote float bowl (available from Thunder Products) attached to the return line of the fuel injection. Dial-A-Jet cured the top end lean condition. The set-up worked great, yielding a crisp broad power band! The Dial-A-Jets could be adjusted for temperature, altitude, engine load, or fuel quality. The installation was simple and effective. More than 3,500 trouble free miles have been logged on this machine.

Does your engine require aviation gas or other high test fuels? Maybe not. Dial-A-Jet can be installed on your carburetors and used to induct many types of fuels or fuel additives such as octane boosters, alcohol (methanol), alcohol blended with nitro, propylene oxide, etc. One of the lowest cost, user-friendly fuel boosters is alcohol (methanol). This is a very easy and inexpensive way to raise your octane while lowering engine-operating temperatures by approximately 150 to 200 degrees Fahrenheit. Dyno tests have shown a 5% to 6% increase in horsepower. Installation is very easy. Install a set of Dial-A-Jets in the conventional manner. Now you will need a small tank mounted under your hood for the alcohol. The tank should have a fuel shut off. A remote float bowl with a needle and seat will also be needed to handle the fuel from the tank to the Dial-A-Jet. Simply hook the Dial-A-Jets to the remote float bowl and you are ready to run. This is very simple and effective, it can be used on any ordinary trail machine to safely boost performance and raise horsepower while lowering temperatures.

Dial-A-Jet is a very cost effective product. Each kit comes with a complete installation and tuning manual. Thunder Products provides full time expert technical support for all of their products.

[bucky katt]

it LOOKS like keihin pilot jets, like the ones that are in the 1969-1976 750 carbs. i have several sets of carbs here i can experiment on, and since i seem to be running a touch lean still, this may be the thing for me to try.


edit : these ARE pilot jets, guess what i'm doing tomorrow! i'll take pictures and document the whole process.

edit 2 : i am still wondering is putting the jets into the threaded holes where a carb synchometer connects would work.  oh boy i LOVE tweaking and tuning!

[bradweingartner]

it LOOKS like keihin pilot jets, like the ones that are in the 1969-1976 750 carbs. i have several sets of carbs here i can experiment on, and since i seem to be running a touch lean still, this may be the thing for me to try.


edit : these ARE pilot jets, guess what i'm doing tomorrow! i'll take pictures and document the whole process.

edit 2 : i am still wondering is putting the jets into the threaded holes where a carb synchometer connects would work.  oh boy i LOVE tweaking and tuning!

IF you put them in the carb sync holes it would suck the fuel out of your bowl like a vacuum.

[bucky katt]

it LOOKS like keihin pilot jets, like the ones that are in the 1969-1976 750 carbs. i have several sets of carbs here i can experiment on, and since i seem to be running a touch lean still, this may be the thing for me to try.


edit : these ARE pilot jets, guess what i'm doing tomorrow! i'll take pictures and document the whole process.

edit 2 : i am still wondering is putting the jets into the threaded holes where a carb synchometer connects would work.  oh boy i LOVE tweaking and tuning!

IF you put them in the carb sync holes it would suck the fuel out of your bowl like a vacuum.

ok, that makes sense to me. i actually have the carb bodies in the office with me and i'm about to drill/tap the first hole. i have several different sizes of pilot jets from back when i tried to get stock carbs to work on an 890 motor. so possibly when i wake up late this afternoon or early evening i'll be able to give a ride report.

[eurban]

it LOOKS like keihin pilot jets, like the ones that are in the 1969-1976 750 carbs. i have several sets of carbs here i can experiment on, and since i seem to be running a touch lean still, this may be the thing for me to try.


edit : these ARE pilot jets, guess what i'm doing tomorrow! i'll take pictures and document the whole process.

edit 2 : i am still wondering is putting the jets into the threaded holes where a carb synchometer connects would work.  oh boy i LOVE tweaking and tuning!

IF you put them in the carb sync holes it would suck the fuel out of your bowl like a vacuum.

ok, that makes sense to me. i actually have the carb bodies in the office with me and i'm about to drill/tap the first hole. i have several different sizes of pilot jets from back when i tried to get stock carbs to work on an 890 motor. so possibly when i wake up late this afternoon or early evening i'll be able to give a ride report.

Did you perform the procedure and test it out?  One interesting thing to check would be to see if fuel is drawn up when the bike is revved up in neutral.  The Dial a Jet tech article suggests that their system has an "automaticness" to it that will draw in fuel according to load (among other things) on the engine.  Revving in neutral doesn't draw the fuel up the tube while under load fuel is supplied. Please post your progress . . .