78 GS1K Carb Rejet? Bad Fuel Economy - KEITH KRAUSE!

[Hoomgar]

Keith, getting those plug reads may not happen. The bike has been running good but I still know it can be better. As you saw in the fouling thread I think I may have other issues. But I would still like to get it jetted right. I want to collect parts awhile if I can before any more work.

In an effort to make it affordable can you help me with knowing what exact parts you would want in it if you were rebuilding those carbs yourself today? Up to know we have been working with what I have but I believe it is time to go the route you originally were telling me to. Get the jet kit! But rather than buy a whole kit, what parts would you like to see me get? I ask because I can most likely get all the Dyna needles, jets, etc... I need if I just know what exact ones to get. Could save me a lot of money.

[KEITH KRAUSE]

Sure Mark. But I'm not sure if DJ will sell seperate parts, especially the jet needles. I've never asked, but if they do sell the jet needles seperately, please let me know and how much.
The DJ part numbers you would need are:
Main jet, DJ138.
Jet needle, DN0304.
Jetting washers, DW0001.
E clips, DE0001.
PS: I had some trouble posting to this thread. I clicked the topic I received as e-mail and it just said "no posts exist for this topic". Then at the site here, it says page 13, but I clicked that and it says the same thing. But I got through. Just strange. :? Even when trying to submit this, I get a message saying the same thing but the message goes through.

[Hoomgar]

Sure Mark. But I'm not sure if DJ will sell seperate parts, especially the jet needles. I've never asked, but if they do sell the jet needles seperately, please let me know and how much.
The DJ part numbers you would need are:
Main jet, DJ138.
Jet needle, DN0304.
Jetting washers, DW0001.
E clips, DE0001.
PS: I had some trouble posting to this thread. I clicked the topic I received as e-mail and it just said "no posts exist for this topic". Then at the site here, it says page 13, but I clicked that and it says the same thing. But I got through. Just strange. :? Even when trying to submit this, I get a message saying the same thing but the message goes through.

Keith, I will get the parts free from a local friend most likely. I am also having the same issue with this thread. Thx for the info!

[Hoomgar]

Test post

[Hoomgar]

There, I got us to page 13 and it seems fixed now.

[KEITH KRAUSE]

There, I got us to page 13 and it seems fixed now.

Yeah. This topic is working normally now.
But I just received an e-mail about Steve's Mac 4-1 re-jet topic, and when I click the link it just says "topic doesn't exist", but it does of course. Maybe just a glitch or something.

[Hoomgar]

Keith, I am getting the entire DynaJet jet kit for this bike. Were going to have everything now to do it right. I also took my intake boots back off and reinstalled new o-rings. Not sure if I had posted that before or not? The smoke this thing gives everyone tells me is black so that is fuel. I really don't think it is oil from leaky seals.

I could use my old set of carbs and completely rebuild them with this new jet kit when it comes and switch over to them? What do you think?

[KEITH KRAUSE]

As long as the carbs are ready for re-jetting, use any you want.
Ready means, completely clean, all o-rings inspected for good or replaced, floats adjusted, all other parts inspected and good.

[Hoomgar]

As long as the carbs are ready for re-jetting, use any you want.
Ready means, completely clean, all o-rings inspected for good or replaced, floats adjusted, all other parts inspected and good.

They are a really nice set Keith. I am cleaning and dipping them now. This is the set from my tips thread though. We need to verify what they are before going any further. See the tech thread from renobruce.

[KEITH KRAUSE]

I made a reply there Mark.
As for using these carbs, I have to stick to what I think you have there. I think these carbs have blunt tipped dummy screws and plugs. Unless I can see something that would change my mind, I can tell you you'll never get these jetted right for lower throttle positions.
What's wrong with using the other set you have? With the DJ kit installed, it shouldn't be too much trial and error to get the carbs set up right, as long as all other tuning is done right. The bike should be on the road and running great quickly. I can already tell you the 138 main will work for your mod's and I believe the needle will end up at either position 4 or position 3 1/2 (jetting spacer used). If I'm off about the main and/or needle, it would be contrary to what has worked in several similar set ups I've jetted or helped jet.

[Hoomgar]

I made a reply there Mark.
As for using these carbs, I have to stick to what I think you have there. I think these carbs have blunt tipped dummy screws and plugs. Unless I can see something that would change my mind, I can tell you you'll never get these jetted right for lower throttle positions.
What's wrong with using the other set you have? With the DJ kit installed, it shouldn't be too much trial and error to get the carbs set up right, as long as all other tuning is done right. The bike should be on the road and running great quickly. I can already tell you the 138 main will work for your mod's and I believe the needle will end up at either position 4 or position 3 1/2 (jetting spacer used). If I'm off about the main and/or needle, it would be contrary to what has worked in several similar set ups I've jetted or helped jet.

Well that is what my plan here was. Since this has been so much grief I wanted to get it where I am using all the parts you know so that we can set it where you knew it would work. I feel this will get it sorted this time.

Is there a way to find out for sure what that other set of carbs are?

I can use the set we have been using for this though like you say, that is not an issue, just down time that I was trying to avoid.

[KEITH KRAUSE]

Don't use those carbs with the dummy screws, please.
Use the set that has the fresh o-rings, floats adjusted, cleaned, etc.
As for down time, it should go quick, IF YOU HAVE DONE ALL THE CARB WORK CORRECTLY AND THE MOTOR/SPARK IS SOUND. I have it narrowed down to only a couple of set ups. There is simply no reason these set ups won't work on this bike, unless there's something wrong that I can't control.
My bike with the 1085 pistons, will ALMOST handle the 142 DJ mains, but it creates a small bog during roll ons. To get the needle circuit perfect, I had to stay with the 138 mains. There's no way your bike will handle the 142's without bogging, especially with less flow from the stock pistons. So 138 is the main you want.
As for the jet needles, I'll say go with them in the #4 position from the top. Should work.
The pilot circuit always takes some time to fine tune. No larger pilot jet should be needed, just pilot fuel screw adjustments. Then of course, air screw adjustments and vacuum synch.
As for the grief of this re-jet, it only seems that way because you haven't got a lot of experience with this. If some others made a thread about their re-jet, I can tell you they would be a lot longer than this one. You really haven't had the bike apart as many times as others who swear they know what they're doing and are using a jet kit all along. If you had gone straight to the bottom position on the stock needles as suggested, you would have quickly learned if the stock needles would work, as that position was their only chance. You now know the stock needles just don't work well, not with K&N's. Re-jetting your bike would be as simple as trying the stock needles at the 5th position, giving up, and buying the DJ kit and following my set up. The needles are by far the most work because you have to tear things apart and re-synch...
The mains can be changed by removing the bowls with a short tool. The pilot circuit is just turning screws.
So go with the above and I believe you won't be taking it apart anymore.
If you still have heavy exhaust, fumes, poor mileage, then something unknown is wrong. Something that is effecting the jetting. Not the jetting itself.

[Hoomgar]

Keith, just an update. I am still waiting on the blasted back order jet kit :x
I'll be checking on that again today.

The carbs I cleaned up are better looking than the set I have on now so I will use them. They are immaculate. I?ll then jet as you said above and we?ll start new so to speak with this.

A quick question. The last time I rode the bike it was idling weird. The RPM?s would want to stay up on me and would take a long time to idle down. I checked the cable. It isn?t that. The throttle is completely returned closed while it is happening. Is this an air leak?

[Jethro]

Did it get worse when the bike warmed up? If so, classic intake leak symptom ya got there buddy. Didn't you just install new O-rings? Maybe one didn't seat well or the manifold screws backed out?

[KEITH KRAUSE]

Yup. Most common cause of a hanging idle is an intake leak (manifold/manifold o-ring/clamp), or a very lean condition (pilot fuel screw too lean/small pilot jet/clogged passages).
Less common, but possible, is a sticking slide. As part of my check list, I always take some aluminum polish and lightly rub out the slide area to a mirror finish.