Carb tuning sequence, AGAIN

[slamonte]

Thanks Keith for sticking with me here. Most of what I've learned about these carbs are posts you (and others) have made to members. I've tried to read most of them and capture the pertainent points. I need to get a roadmap or good understanding and then I can tackle most anything. BUT at my age the confusion factore is much greater than it used to be! LOL So now I need alttle more explaining and checking...

I was thinking at least 125 mains from prior post I have read. I just don't have 125 or greater mains right now and can't (WIFE) spend the money right now to order the DJ3 kit. Is there a way we can dial in with 122.5 main and 17.5 with stock needle at position 5?

I think my son has posted before and you gave him some suggestions prior to us getting this other carb set with larger jets.

I'm chem dipping the UNKNOWN carb set small parts now and have them ready when you get back to me. I think we can get closer to operating right with 122.5 and 17.5 than leaving it 117.5 and 15. I'll then save for DJ3 kit and rebuild the other set of carbs with them.

Thank everyone and especially you Keith for all your carb help. It is amazing how many of these questions the GSR gets daily. Time to do a consolidated paper (similar the CV rebuild) and add in a lot of these extra tips. There has been a ton of them throughout the various post from you and others (not contained in CV rebuild or Suzuki tuning supplement. (i.e no RTV on any surface where gas touches -- so no RTV on intake boot). I'm sure a lot of people have tried this method and failed..

[renobruce]

I know cost is always an issue for all of us, but if you can talk your wife into letting you get the DJ kit, it might end up saving your marriage or you pulling all your hair out. :-D

Others have tried dialing in their carbs (especially the VM carbs) using stock components, and it usually turns out to be quite a bit of work and frustration. After reading some of the posts to that effect, I bought the DJ kit for my 78 1000 (with pods and 4-1 pipe). Keith recommended a starting point, and it was spot-on. A few minor tweaks and my bike runs perfect.

[KEITH KRAUSE]

I was thinking at least 125 mains from prior post I have read. I just don't have 125 or greater mains right now and can't (WIFE) spend the money right now to order the DJ3 kit. Is there a way we can dial in with 122.5 main and 17.5 with stock needle at position 5?

I think my son has posted before and you gave him some suggestions prior to us getting this other carb set with larger jets.

I'm chem dipping the UNKNOWN carb set small parts now and have them ready when you get back to me. I think we can get closer to operating right with 122.5 and 17.5 than leaving it 117.5 and 15. I'll then save for DJ3 kit and rebuild the other set of carbs with them.

You had me confused from your first post saying you already had "stage 3 jetting". At least now I understand you have the stock jet needle.
It sounds like you bought another set of carbs so you could get bigger jets?? Kind of an odd way of getting jets. Maybe I misread? Was there another reason to get another set?
To reply to your quote above, many times the stock needles give poor results and it's best to get the kit. Saves time and frustration. However, with the cheaper pods, you sometimes can get things right with the stock needles and larger pilot and main jets. Depends on flow and engine condition and other basic tuning. Just so you know. Jetting is best done once and forget it. The kit is recommended.
Whichever carb set you use, be sure all the air and pilot screws move freely, slides are good, float valves, floats are set right at .94", all inner o-rings in good condition, etc. Be sure all parts are there and all hardware is good. You'd be amazed at what can happen to a set of carbs over the years, from both the elements and at the hands of butchers. Inspect them completely. Don't allow cleaner to contact the rubber parts.
As for the jetting, keep in mind that the stage 3 DJ kit uses a 138 main (most often used). A DJ 138 is approx' the same size as a 130 Mikuni main. The two makers just have a different way of sizing their jets. DJ, by actual hole size (1.38mm), Mikuni, by the amount of CC's that will flow per minute. This main is designed to run with the better flowing K&N pods AND a QUALITY pipe. Since you have cheaper pods, I'd decrease the size 2.5 to 5. I can only assume the pipe is quality. No way for me to be sure if a 125 or 127.5 is the right one but the general rule of thumb is to go richer and work your way back (leaner). In my opinion and from past experience, the 122.5 you have will starve the bike at 3/4 to full throttle. It may/may not be real noticable but I wouldn't start off with those smaller mains. If the bike isn't flowing as well and if you're at a higher elevation, then the 122.5 may work fine.
I would try the jet needles at their richest position, 5, e-clip in the bottom groove. Be sure the two factory plastic jet needles spacers are re-installed per factory order, thicker spacer (ring) directly on top the e-clip and thinner spacer under the clip. Test the needles at 1/3 to 1/2 thottle.
I generally try to make the stock pilot jet (15) work if I can. That means adjusting the pilot fuel screws underneath richer to assist the pilot jet. If no joy by the time the screws are 3 turns out, I go to the 17.5 pilots. Test the pilot circuit at minimal throttle, steady cruise about 35/40 mph in 4th/5th gear. Again, it depends on flow if you really need the larger pilots.
One other thing is I don't know is what elevation you're at. If you're fairly high up that effects the jetting enough to make a change in suggestions.
Be careful when high speed testing.

[slamonte]

OK Keith & Renobruce you convienced me to spend the money on the DJ3. I bought them tonight with rush delivery. I will also see if I can pickup K&N pods tomorrow. I want to keep everyones effort to a minimum and do it right the first time. Time does have value!:-D

The extra set of carbs came with another parts bike we picked up cheap. It just happens to have the larger jets...just coincidence. The carbs are cleaned up and ready to assemble when the DJ3's arrive. I know that Kieth has a lot of experience with these VM's and the DJ3, so we can get a good working base from Keith's knowledge.

[slamonte]

I am in the Dallas area at 350 ft above sea level.

[salty_monk]

Need a home for your spare carb set

I'm about to embark on the same process.... good luck with it

[KEITH KRAUSE]

With the stage 3 kit, K&N pods and quality pipe, I've found that the 138 main, jet needle e-clip in position 4 from the top, and stock 15 pilot jet, work well much more often than not.
Be sure to also remove the floatbowl vent lines as I mentioned before.
I'd initially set the pilot fuel screws to 1 1/2 out from LIGHTLY seated and go from there. Do what the minimal throttle position tests/plug reads tell you to do.
I set the side air screws to 1 3/4 and then fine tune using the highest rpm method when ready.
Whenever you change or disturb the jet needles on VM carbs, you must re-bench synch and vacuum synch.
After the jetting is right, play with the advance timing as I mentioned to get the most out of the bike.

[TheCafeKid]

not to but in but Keith im ordering those jets for MY bike as we speak..and i cant decide ...125 or 127.5?? or bigger still??

Thanks
TCK

[KEITH KRAUSE]

not to but in but Keith im ordering those jets for MY bike as we speak..and i cant decide ...125 or 127.5?? or bigger still??

Thanks
TCK

No way to know for sure. I'd probably go with the 127.5 unless you ride in mostly higher elevations. If you're in richer conditions, then I'd probably go with the 125.
Only testing will tell.

[TheCafeKid]

No way to know for sure. I'd probably go with the 127.5 unless you ride in mostly higher elevations. If you're in richer conditions, then I'd probably go with the 125.
Only testing will tell.

127.5's on the way...Im sure ill be hittin you up for info on our thread in a couple days...my intake rings and jets should show up by thursday or fri...

Thanks again sir!!

[spdjunkie]

Good suggestion except they don't sell them any more.

Sorry, was not aware. At least now there's no chance of sucking mercury into the intakes. :-D

I did build a guage manometer from guages at grainger with decent results, but if I had it to do over, I'd have used liquid filled guages.

[slamonte]

Keith, a couple questions before we start.

1. is there a chart or something that shows mukuni numbering of jets versus DJ? It always help me to eliminate any confusion that crops in.

2. 125 & 127.5 I assume relate to the mukuni numbering. What is the equivalent DJ?

3. do you want me to start with the mukuni equivant of 127.5?

Thanks

[KEITH KRAUSE]

Keith, a couple questions before we start.

1. is there a chart or something that shows mukuni numbering of jets versus DJ? It always help me to eliminate any confusion that crops in.

2. 125 & 127.5 I assume relate to the mukuni numbering. What is the equivalent DJ?

3. do you want me to start with the mukuni equivant of 127.5?

Thanks

Yes, there's a chart around but I'm not sure where it is.
A 127.5 is a Mikuni jet. Mikuni jets change in increments of 2.5
I'd try the 127.5

[KEITH KRAUSE]

Hey, wait a minute.
slamonte, you said you were going with the DJ kit.
Two of you asking questions in the same thread can cause confusion, especially whem I'm not awake yet but in a rush to get out the door.
For your 1000, I'd try either the 127.5 or the 130. No way to be sure which.
Rule of thumb, go with the richer jet to start, as long as it's a reasonable choice.

[slamonte]

Help!

I got my DJ3 kit in today. I'm confused to wether I need to drill out my slide. A drill bit came with the kit, but the instructions are very vaige. I want to make sure before proceeding. You'd think with the cost of these jets you'd get a better install document. The pages are poorly zeroxed and out of sequence. Dynojet does not have an online instruction that I could find.

I have a 1979 GD1000E with VM carbs.