Stevo,

I've been building and racing cars and motorcycles for 45 years...I have multiple national trophy winners. Customs, classics, you name it. Worked professionally as a mechanic and then went into engineering. Worked in the pits as a mechanic for a national race team. You wrenching in your garage is great but I wouldn't let you touch anything of mine because you have proven here you know nothing. Your all talk. You have shown nothing to substantiate your claim that your method is how it "should" be done, but you continue to spew it out on the web. I have shown the manufacturer's method which is how I explained it originally. For those that know the proper way to tune a carburetor, you have shown how little you know and made a fool of yourself. Good luck with your wrenching.

You have also done nothing to help the original poster...just mucked up his thread with your crap.

Quote from: dennisgb on December 19, 2014, 10:22:19 PM
You have also done nothing to help the original poster...just mucked up his thread with your crap.

Backup the truck Buckwheat..I thought I was on your Ignore List?

And your wrong..I posted mostly sentences while you where dropping paragraphs in every post, so actually you mucked it up more. Oh yeah I forgot, your right and I'm wrong so in your mind I mucked it up more 

Let me also quote myself from the first page the most honest statement I could make on the subject (minus the part you can't let go)

Quote from: Suzuki Stevo on December 19, 2014, 09:45:19 AM
You are trying to create a solution for a problem that doesn't exist.

One of those short tips for a muti tip screwdriver is all you need if you want to adjust the Idle Mixture with the carbs on the bike

Quote from: dennisgb on December 19, 2014, 10:16:47 PM
Stevo,

I've been building and racing cars and motorcycles for 45 years...I have multiple national trophy winners. Customs, classics, you name it. Worked professionally as a mechanic and then went into engineering. Worked in the pits as a mechanic for a national race team. You wrenching in your garage is great but I wouldn't let you touch anything of mine because you have proven here you know nothing. Your all talk. You have shown nothing to substantiate your claim that your method is how it "should" be done, but you continue to spew it out on the web. I have shown the manufacturer's method which is how I explained it originally. For those that know the proper way to tune a carburetor, you have shown how little you know and made a fool of yourself. Good luck with your wrenching.

Congratulations, you made it farther than I ever did wrenching...now if you will just pull your head out of your arse and stop trying to prove yourself right 

EDIT: Ok I quit, as long as somebody else quits 
But I also know you have to get the last word in, so make it good, my work is done here/

And never forget: the GS is not rocket science, it's more like tractor science.

Does seem to me though that the carbs are assembled with the idle screws set at a certain number of turns and then plugged before they are installed on the engines at the factory?  Doubt they adjust them like Mikuni says hot and running after assembly. 

Is it possible that in many cases BOTH sides end up correct?

That is, at roughly 1 ATM pressure (so, reasonable altitude near sea level, not the Andes), with non-EtOH fuel of average developed-world quality, a decent air filter of OEM quality, and no leaks, that both Mikuni book followers and 3-turns followers will end up close?

Quote from: dennisgb on December 19, 2014, 06:42:54 PM

Him -The Mikuni manual is clear. That is the "right" way to adjust the pilot circuit-

You -Stick an O2 sensor up your pipe and measure the mixture ratio at idle and report back.

I can easily imagine a situation where Mikuni might quote an imperfect procedure- even if only for simplicity's sake.And also because their procedure get's it 'near enough to perfect'.
So dont be surprised if we laugh at both of you (but mostly him)

Quote from: Rallyfan on December 19, 2014, 11:49:46 PM
Is it possible that in many cases BOTH sides end up correct?

That is, at roughly 1 ATM pressure (so, reasonable altitude near sea level, not the Andes), with non-EtOH fuel of average developed-world quality, a decent air filter of OEM quality, and no leaks, that both Mikuni book followers and 3-turns followers will end up close?

Every ride I go on over an hour takes me from Sea level over one of Washington's many Mountain Passes, so I never got hung up on trying to make it perfect, all my bikes are EFI now anyway. It's kinda like an oil thread...do what gives you the most piece of mind.   

Fair enough. I do envy EFI but that's another story.

Quote from: Rallyfan on December 19, 2014, 11:49:46 PM
Is it possible that in many cases BOTH sides end up correct?

That is, at roughly 1 ATM pressure (so, reasonable altitude near sea level, not the Andes), with non-EtOH fuel of average developed-world quality, a decent air filter of OEM quality, and no leaks, that both Mikuni book followers and 3-turns followers will end up close?

3 turns out is close to the end of travel. Most tuner's understand that about 2 is optimum. This is measured by how the engine runs after tuning or rejet. Most bikes in the USA are set lean from the factory to meet EPA emissions. One size up on jet size usually improves running without any other mods. If your at 3 turns and are using the RPM method for tuning you could consider changing jet size but it's probably ok.

If you are at 3 turns and just set them like this because you read it on the web, ask yourself the following questions:

1). Do I know if I'm running rich or lean?
2). What are the consequences of running rich or lean? Can it damage the bike?
3). Do I have optimum throttle response? Do I know the difference?

Altitude and weather, temp and many other conditions in your particular area also effect how your engine runs. How can one setting fit all situations? Fuel type and additives also have an effect.

The reason that the book takes you through running "your" engine is to insure that the fuel mixture is set properly for your bike, where you are, with the fuel you are running.

Yes you guys are right...it's not rocket science, but it also isn't plug and play.

Krav,
Regardless of what method you use to set your mixture screws...you do understand it's something you only need to do ONCE in a motorcycles life, if at all? 

You are over thinking the whole process of turning a screw, it's not hard to access and adjust the mixture screws once the plugs are gone, take a screwdriver tip as I have mentioned before, add a bit of fuel line to it for a handle, leave it in the watch pocket of your pants...that way you will have it around and you can wank with your mixture screws every ride if you want?

The one in this photo is over 40 years old, it's really all you need even if you feel the need to tweak the mixture screws daily.

Can I stick my oar in 

When carbs are made in the factory they are set up and adjusted on rigs, the manufacturers use an inert gas, vacuum pumps, flow meters and analyser's to check the delivery rates and mixture strengths. It takes seconds then the plugs go in. The bike manufacturers state these figures and they are a compromise between economy. performance fuel strengths and emission legislation. The idea is they work straight out of the box and can go straight on the bike while its on the line without wasting any time making major adjustments..

If its some highly tuned race engine or if you are obsessed with getting another 0.001hp out of it there may be a case to answer in fiddling with the carb settings n conjunction with other work but otherwise leave well alone, you are not going to see any measurable improvement.

Dennis?.....what you say holds some substance but to apply it on a GS5 with an average rider.....nah........total overkill. If adjusting the pilots was a necessity......they wouldn't be blanked off and to be brutally honest, missing pilot plugs are a major turn off to any potential (and clued up)  buyer.

Quote from: sledge on December 20, 2014, 08:51:36 AM
Dennis?.....what you say holds some substance but to apply it on a GS5 with an average rider.....nah........total overkill. If adjusting the pilots was a necessity......they wouldn't be blanked off and to be brutally honest, missing pilot plugs are a major turn off to any potential (and clued up)  buyer.

I'm beginning to understand that. Tuning is a difficult subject to discuss...understanding that the pilot screw position tells you if your pilot jet size is right is a little beyond the average user. The question I have is how can you clean your dirty carbs if you don't take the pilot screw and jet out? So you have to break the cap the first time you clean your carbs...and then you have to set them after you put them together.

Will a static setting work? Probably. Is it optimum? Highly unlikely. So if you hear that funny popping sound, or a slight backfire when backing down...you should be aware that you can fix that. Or when you hit the overlap at 1/8 throttle and there is a little hesitation, maybe if you adjusted those screws you could get rid of that.

Only a very few buyers are savy enough to look at the bottom of the carbs to see if the factory screw caps are on there.

I just viewed a video a buddy sent me of his bike on his dyno, showing the fuel mapping software going through it's paces...it's sort of funny talking about something as simple as a pilot screw and getting nothing but flack.

Good luck to all you guys. I've decided to leave this forum. Not worth the effort.

Quote from: dennisgb on December 20, 2014, 09:16:00 AMGood luck to all you guys. I've decided to leave this forum. Not worth the effort.

Dennis,
Let me be the first to say..don't just take your ball and go home, you obviously have decades of experience, your only flaw is your incessant tunnel vision in thinking there is only one way to skin a cat, please stay and share your knowledge   

I'd hate to see you go, too, Dennis.  I don't know enough about this topic to chime in....but I've learned a lot from the spirited debate.

Roaring via Tapatalk.

Only a very few buyers are savy enough to look at the bottom of the carbs to see if the factory screw caps are on there.

That's correct.....but they are around, as I have just demonstrated   

Regarding cleaning, I have had satisfactory results without touching the pilot screw, after all it only governs air flow and doesn't', or shouldn't!!  see any fuel.

A missing plug wouldn't put me off buying a GS5, but I would be aware that it may put someone else off and it does indicate that someone has been at the carbs and you then have to ask what was that person doing and more importantly did they KNOW what they are doing.

Cant see why you feel you have to leave.....Its not a contest and you are under no obligation to say anything, people will either take your advice on board and believe what you say or they wont, no sense in getting upset if they don't. The mistake a lot of people in here make is paying more attention to who is doing the talking rather than what's being said......frustrating sometimes but just let it ride, its not your loss.

I'm going to give this one more shot.

This is not an argument...I have been trying to present the methods used by every motorcycle tuner that I know...along with manufacturer recommendations, and most of the rest of the web.

There are two different types of pilot fuel/air delivery systems. There are pilot screws that adjust the amount of fuel being delivered and pilot screws that adjust the amount of air being delivered to the pilot jet outlet.

In either case the fuel and air must be mixed and delivered to the throat of the carburetor. The pilot jet pulls fuel from the float bowl which is mixed with the air coming from the air screw chamber at the tip of the air screw. The air and fuel are connected together. This means that fuel can get into the air delivery chambers and thus can plug the air screw and or the chambers or both. It is common practice to remove the pilot air or fuel screw, spring, washer and o-ring during cleaning and rebuilding. The o-rings degrade over time and should be inspected and replaced. Damaged o-rings will allow air or fuel to escape past them and thus make it difficult to adjust the mixture.

When cleaning and rebuilding carburetors parts should not be left installed during cleaning. The small air and fuel passages can plug with dirt from the cleaning process if there is no place for dirt and debri to go (the mixture screws left in act as plugs if not removed). The openings in the pilot jets and air openings are very small .025"-.040" and get plugged very easily particularly when the engine is only run occasionally. Carb cleaners and compressed air generally do not work to clean these small orifices. Small wire probes are generally used to clear these small orifices. Care must be taken to not damage these openings.

It is very rare not to find some dirt, sludge, varnish or other debri in a carburetor that has miles on it and has not been opened for a while. Sometimes just sitting for a month with fuel in the carb will plug it up. Fuel sitting in the float bowl can find it's way into the air junction at the pilot jet. Many fuels today contain ethanol which will produce organic growth in a little as a month of sitting in a carburetor. Poor idling, popping and backfiring are symptoms of a dirty pilot circuit. These also can be symptoms of an improperly adjusted pilot circuit.

Hesitation during the crossover from the pilot circuit to intermediate or main circuit at approximately 1/8 throttle is also a symptom of a dirty or improperly adjusted pilot circuit.

Information on proper adjustment of carburetor pilot circuits is available all over the web. There is a misunderstanding between manual recommended static settings for "Start-Up" after rebuilding or cleaning carburetors. People all over the web have construed this information as the "Recommended" settings. It is not. This is a simple statement of fact. The recommended setting is in order to get the engine running. Once warm the RPM method is recommended by every motorcycle manufacturer as well as the carburetor manufacturer's for setting the pilot circuit.

Manufacturer's were forced to cap the pilot screws in order to meet the requirements of the EPA. The factory setting is different depending on where the bike will be sold. I know this because I bought a CBR California bike and it would not run in Minnesota. The main problem with capped pilot screws is the bike will eventually need to be tuned or need the carbs cleaned or rebuilt. So those that keep citing the fact that the pilot screws are capped from the factory so it makes no difference need to consider this was a compromise and in fact every motorcycle sold is set too lean from the factory and thus is not running at optimum.

Now, those that have said they never had to worry about taking the pilot screw out must be living in the cleanest place in the world with perfect fuel, because I have never taken a carb apart that didn't need to be cleaned.

I wonder if this carb needs to be cleaned? Do you think the pilot circuit "could" be dirty?



Sure this is an extreme case, but I have seen that black goop in a lot of carburetors.

Usually they look something like this:



This isn't about forcing some pro tuning method. It's really is the method that is in most every shop manual.

This is an excerpt direct from my CBR manual:



And Honda Shadow 750



Norton



These are manuals I have for my bikes, but you could go into any manual and find a similar description on how to do this.

It is the method that is used by everyone...except GS500 owners on the GSTwin Forum.

Far out. .. I missed this thread till now! ... I like gsJack quote the best. .. 'don't mess with your carbs and they won't mess with you' , or something like that. ...

The rest is just a slide rule pissing  match.... sure the things can be tweaked to the n'th degree. .. for frag all power gains... but in the mind of the tweakers is the satisfaction of rightness....

The rest of we Muppets just leave shaZam! alone and ride along happily mostly...

I might have to check my bike though. .. it's had e10 sitting in its tank for a few months at a time quite often this year. .. it starts and runs fine every time too. ... MUST be something wrong with it eh! ...

Now excuse me while I finish chuckling after re reading some of the posts. ... I do love a experts pissing match!

Quote from: dennisgb on December 20, 2014, 08:14:19 PMThe factory setting is different depending on where the bike will be sold. I know this because I bought a CBR California bike and it would not run in Minnesota.

I am getting this image in my mind............Dennis speeding towards the state line on his CBR then wondering why it suddenly spluttered to a halt the instant he crossed it because the pilot screws needed another 1/2 turn

Maybe they should be putting up signs.....


----------------------------------------------
                 XX WARNING XX
       You are now entering Minnesota
      Adjust your pilot jets accordingly
                 Have a nice day

----------------------------------------------