Who can help me out with 79 GS1000E carb sleuthing? VM26SS with Dynojet questions

[oldGSfan]

That is my recollection from the mists of time, but in the case of these carbs, what I now understand is that it was used in conjunction with the screw DJ provided to yank the cap off the 'emissions mixture screw'. Yeah that sounds legal! I'm glad to hear this is the case (as I understand it) and the needle jet aperture is not drilled out.

The one and only time I used a dynojet about 10 yrs ago, the drill bit was used drill the bottom of the slide (I think that's the term). I'm not sure why it needed drilling.

[KEITH KRAUSE]

zed, I understand the operation of an air jet. I understand what you're saying about your air corrector. Unfortunately, your corrector is nothing more than a restrictor.
In my previous post, I focused on your corrector possibly increasing air flow because I said you couldn't actually mean decreasing air flow. Decreasing air flow, in this case, is going backwards.
I don't need to get into the entire jetting system. If you have a problem at any point, the system doesn't work well. With your air corrector, you have a problem at point 1,2,3.....Point 1, not enough volume of air flowing through the corrector. The rest of the system, as designed, won't have enough air to do it's job, which is to provide a correct air/fuel ratio properly atomized as it enters the main bore. Point 2, the corrector's reduced air flow enters the needle jet's aeration passages. Reduced air flow equals less atomization as it mixed with the fuel. Point 3, with the mixture entering the main bore not properly atomized, good combustion will be compromised in the combustion chamber. The entire system has a problem right at the beginning.
You try to say the air corrector makes a VM carb operate similar to a VM smoothbore carb as far as operation between approx' 1/5 to 3/4 throttle positions which is when the needle jet/jet needle regulates mixture flow. A smoothbore carb is designed to draw fuel a little easier through the needle jet. Drawing fuel easier does help richen the mixture some but it's not enough to fully compensate for the increased air flowing through the main bore. The mixture entering the combustion chamber will be lean.
Quality pods and a pipe equal increased flow. To safely benefit from this increased flow and not over heat the engine, you have to increase the fuel in the mixture. At approx' 1/5 to 3/4 throttle positions, with regular VM's or smoothbores, you raise the jet needle to pass more fuel. You don't try to counter the increased flow through the main bore by installing a restrictive component in the system. You wouldn't take a free flow performance header and slap a restrictive muffler on it to avoid a jetting change. You don't add air just to take it away. To compromise the VM's ability to atomize the mixture in the needle jet and use that as a substitute for increasing fuel flow to achieve a correct air/fuel ratio is backwards jetting and creates bigger problems than the "flat spots" you mention that don't even exist if the bike is tuned, jetted and maintained correctly. Conditions in the UK are generally very different than in Southern California. With more humidity and cooler temp's, running a lean mixture in the UK is easier to get away with than in Southern California. You have to consider the climate the bike will be running in when deciding how to change the jetting.
If someone wants to spend extra and drill holes in their carbs instead of adjusting the e-clip on the jet needles, go ahead. If someone believes that making your carbs shoot an improperly atomized stream of "richer" mixture into the main bore somehow results in a correct air/fuel ratio, then I've got some prime swamp acreage that's perfect for building on that I'd like to sell.

[KEITH KRAUSE]

By the way, Tom, check the fuel "T" and fuel connector tubes for leakage. Generally, you check before mounting by adding enough fuel. Since you already mounted them just be sure there are no leaks.
The stock, rubber coated tubes can leak if they're disturbed or "dry out" if not in contact with fuel for a time. If there is any leaking, the tubes often swell back up and seal again but not always.
Also, do you have a factory manual to show you all the assembly steps? Just wondering. One step involves the vacuum synch. Many of us, depending on which bike, just set the vacuum levels so the difference between the lowest level and highest level is no more than 2 cmhg. Closer is generally better. For your 1000, the factory recommends you set cylinders 2 and 3 a little lower (about 2 cmhg) than cylinders 1 and 4. A tad less vacuum results in a richer mixture than the cylinders set at higher levels and this compensates for the inner cylinders running a little hotter than the outer cylinders. The factory recommends the slightly richer flow to cool the hotter cylinders. If it's difficult to set them this way and still remain in the 2 cmhg overall difference range, then just set them within 2 cmhg overall. You don't want to try to be perfect and over heat the bike by running it too long.

[zed1015]

zed, I understand the operation of an air jet. I understand what you're saying about your air corrector. Unfortunately, your corrector is nothing more than a restrictor..

Correct but it is a restrictor of a specific size for this application.. And Yes! you don't need to go into an in depth explanation of the carburettors independent but overlapping fuelling stages as that has been a big part of my business for many years. And specifically modifying and boring out stock 26 and 28mm VM's to exceed the performance of the factory 29mm smoothbores.
Your exhaust analogy bears no relation to the air correctors function and i'm sorry that you can't or won't fully comprehend how they work and how their size alters the A/F ratio without adversely affecting atomisation through the needle jet and how a reduction in their size can also allow the use of a smaller main jet ( Compared to the needle lift to try and address the same issue) for better throttle response whilst not altering the overall fuelling or creating a lean condition .
If you think they are backwards jetting then why did Mikuni ( who just possibly might know a little about carburation ) fit an adjustable air jet in the same needle jet tube air bleed for the same exact reason and only on their carbs that are designed to run open or with stacks for maximum air flow. .
What exactly do you think the function of the Mikuni BS30/97 jet is and why and for what reason it is adjustable ( keep the answer to yourself because i already know ).
Thousands have been successfully fitted to machines worldwide in the past 40 years and achieved the result expected , USA included and not just the UK and they do the job they are designed to do regardless of global location, temperature, altitude or atmospheric conditions.

[oldGSfan]

Playing Henry Kissinger here - I will try it 'as is' and see how it runs.

I have a crappy issue to deal with, a broken exhaust stud. So the head looks like it will have to come off. I am financially challenged right now and once back together I will see if I can get it to run on the stuff I have, no correctors. If it won't run right I will try them. My other alternative is returning to stock but that's another can of worms, sourcing a stock airbox etc. You guys are way beyond me on carb theory, I appreciate your inputs.

I'm sort of conflict averse and don't want my question to turn into an issue between fellow GS fans.

[gs11ezrydr]

That is my recollection from the mists of time, but in the case of these carbs, what I now understand is that it was used in conjunction with the screw DJ provided to yank the cap off the 'emissions mixture screw'. Yeah that sounds legal! I'm glad to hear this is the case (as I understand it) and the needle jet aperture is not drilled out.

Most kits have a drill bit and a sheet metal screw to remove to mixture screw plug,Carefully drill a hole in the brass plug and screw the screw into the hole and pull it out..Some kits have another different sized drill bit to drill the slide lift hole.By drilling the slide lift hole it causes the slide to lift faster increasing throttle response..

[KEITH KRAUSE]

zed, I certainly wasn't trying to school you on any part of carburetion. I make a comment with the understanding that other members may be reading/interested.
I'm convinced your way is not the right way. Adjusting the jet needle is, plus it doesn't cost a thing or create a possibility of damaging your carbs with drilling. My thinking is you joined this site to make money. That's not a crime or me trying to put you down. But when you join a site and make claims, be aware that others may not agree with you. I want to see members here, many that I've ridden with and spent time with, make what I feel is the best decision. I'm not saying your air correctors don't work, I'm saying they don't work well enough. Restricting air flow in a component to something less than the factory intended, is the wrong way to counter a significant increase in air flow through the main bore. I don't care about what's going on inside smoothbores. Tom's carbs are not smoothbores. Installing air correctors isn't going to turn his carbs into smoothbores. I'm not impressed with how many people you say are happy with their air correctors. There are much more people that are happy with raising the needles and better operation.

[KEITH KRAUSE]

I'm sort of conflict averse and don't want my question to turn into an issue between fellow GS fans.

No issue from my side, Tom. I think zed feels the same.
Difference of opinions and sharing knowledge/experience is why forums exist.
Is there enough of the stud to grab with a tool?

[Sandy]

By the way, Tom, check the fuel "T" and fuel connector tubes for leakage. Generally, you check before mounting by adding enough fuel. Since you already mounted them just be sure there are no leaks.
The stock, rubber coated tubes can leak if they're disturbed or "dry out" if not in contact with fuel for a time. If there is any leaking, the tubes often swell back up and seal again but not always.
Also, do you have a factory manual to show you all the assembly steps? Just wondering. One step involves the vacuum synch. Many of us, depending on which bike, just set the vacuum levels so the difference between the lowest level and highest level is no more than 2 cmhg. Closer is generally better. For your 1000, the factory recommends you set cylinders 2 and 3 a little lower (about 2 cmhg) than cylinders 1 and 4. A tad less vacuum results in a richer mixture than the cylinders set at higher levels and this compensates for the inner cylinders running a little hotter than the outer cylinders. The factory recommends the slightly richer flow to cool the hotter cylinders. If it's difficult to set them this way and still remain in the 2 cmhg overall difference range, then just set them within 2 cmhg overall. You don't want to try to be perfect and over heat the bike by running it too long.

As for the fuel Ts I just rebuilt an old set of VM28s and the Ts were dried and loose enough they would actually fall out of the holes. I stuck them in a jar and covered them gas and a few days later they fit nice a snug and tight. As for longevity my VM26s had the same issue after being parked for several years after I bought it and I applied the same fix and they have been fine ever since. That was 2003. I'd say 18 years is a pretty permanent fix. Good to see you on here occasionally Keith.

[oldGSfan]

I bench checked the float levels and T's, all good on that. I do have the factory instruction thanks to Bikecliff which details the synch with center 2 a bit lower. I have a good fan that I use to both cool the bike when synching and to blast the fumes away from me.

On the stud, there isn't much there to grab on, or weld to. I'm kicking myself for not checking when I got the bike, sometimes the excitement of seeing something so cool clouds my instincts.

As an avionics engineer and systems design 'authority' (or so they call me) I am always subject to peer review in all the requirements and con-ops I author. It's healthy to have the back and forth I just see things go sideways a lot, if emotions get involved, and I'm not seeing that in either response so that's cool.

As for the fuel Ts I just rebuilt an old set of VM28s and the Ts were dried and loose enough they would actually fall out of the holes. I stuck them in a jar and covered them gas and a few days later they fit nice a snug and tight. As for longevity my VM26s had the same issue after being parked for several years after I bought it and I applied the same fix and they have been fine ever since. That was 2003. I'd say 18 years is a pretty permanent fix. Good to see you on here occasionally Keith.

[zed1015]

zed, I'm convinced your way is not the right way. Adjusting the jet needle is, plus it doesn't cost a thing or create a possibility of damaging your carbs with drilling. My thinking is you joined this site to make money.

Lets get one thing straight Keith.
I didn't join this site to make money and i really don't care what you or anyone thinks.
There is no "drilling " involved so please get your facts correct before making inaccurate statements...
I was INVITED here by other GSR members solely because of my unique choke plunger refurb service and the air jets that successfully solved their running issues after everything else failed to give satisfactory results, including lifting the needles.
If the choke plunger repair and air jets didn't work i wouldn't have been asked to join.
I don't give a flying fu*k about making money and i don't need any more than i already have.
The price i charge for the service i was asked to offer here barely covers costs but that's not why i do it.
I gave genuine advice on this thread ( like i have on many others including you own float bowl gasket sealer query ) and gave the OP an explanation on what he had and an alternative to what he thought was an incomplete Dynojet kit and that's it.
You thought i was an easy target and used the OPs thread as a platform to force your unsolicited opinion on the air jets which now appears to have had an ulterior motive but i'm not so go try it on with someone else.
If you have an issue with that please keep it to yourself in the future. nobody else seems to have the the same problem as you.

[1978GS750E]

Quote "I don't give a flying fu*k about making money and i don't need any more than already have."

Then why the links to your products in your posts?

[zed1015]

Quote "I don't give a flying fu*k about making money and i don't need any more than already have."

Then why the links to your products in your posts?

Only to make them easy to find for anyone who needs them.
It was suggested by a couple of satisfied members.
I'll remove them or get admin to remove them if it's a problem.
The only losers are those who don't know there's a fix for their obsolete choke plungers or alternative solution for their fuelling issues .

[Sandy]

Only to make them easy to find for anyone who needs them.
It was suggested by a couple of satisfied members.
I'll remove them or get admin to remove them if it's a problem.
The only losers are those who don't know there's a fix for their obsolete choke plungers or alternative solution for their fuelling issues .

I don't see a problem. We have other members, long term members, who advertise their products here that have been very helpful to many of us.

[oldGSfan]

Well alrighty then! That went well.