What are all possible causes of a lean condition?

[Jethro]

I've been thinking about trying the carbs from the 81, but they need to be rebuilt. I have poached all the best parts to make sure the 83 carbs are perfect (air screws, float jet needles and seats, etc.). Also, they were jetted for a stock airbox, which I am temped to throw in the 83 as well. Of course, the 81 never really had all it's problems worked out either, so that may not help me.

I'd love to use that colortune, Pano, that's awesome that you got one. Hopefully I'll be able to cancel my time on the Dyno manchine for the week after the ride!

[scotty]

I've been thinking about trying the carbs from the 81, but they need to be rebuilt. I have poached all the best parts to make sure the 83 carbs are perfect (air screws, float jet needles and seats, etc.). Also, they were jetted for a stock airbox, which I am temped to throw in the 83 as well. Of course, the 81 never really had all it's problems worked out either, so that may not help me.

I'd love to use that colortune, Pano, that's awesome that you got one. Hopefully I'll be able to cancel my time on the Dyno manchine for the week after the ride!

i have a perfect set from my 83 that you can try if you will pay the postage both ways. you will have to use a smaller main jets though --i have 150s in there now. And they definitely dont need ballancing either.

If you would like, you can also try my no air filter box K&N setup also

[Jethro]

Scotty, that's a great offer. I'll see how I make out with Pano's colortune next weekend and if I still can't get things right, I'll be in touch! Thanks!

[Jethro]

Well I have good and bad news to report on this issue.

The good news is that I have mostly resolved my issue.

The bad news is that I'm an idiot.

Basically, I was pretty backwards as to how my bike was running. It wasn't running lean, it was running way rich! In my mind the plugs would have been sooty and black if it was running rich. Well, live and learn, because I rasied the needle way up and all my top end surging went away. My plugs must have been clean and white from too much fuel washing them or something. I don't really understand it, but I have vowed to no longer check my plugs. I'm just gonna get it so it feels right, then see how the plugs are looking.

So now the top end feels perfect, but my pilot circuit is acting up. It seems right at the transition from the pilot to needle circuits, I get a little flat spot. I may have raised the needle a little too much. Also somewhat rough at take off, but that might be a carb synch issue. Or I might be expecting too much from my 22 year old machine!

Also, my mixture screws are impossible to set. They have absolutely no affect on idle speed unless I bottom them out. Then the engine coughs. But the do affect how the bike runs on the road. So how do I set them right? It sucks to have to road test between every quarter turn of those screws, but I promise you, turning them 3 turns in either direction has not one affect on idle speed. Aren't you supposed to set for highest idle on each carb and then reset the idle adjuster between each adjustment? What a pain, but at least I am making real progress. I am close, real close to a perfectly running bike!

[pano]

Sounds good I am glad there is progress. What position are the needles at now?

The idle screws adjustment is mainly why I picked up the colortune. When I adjusted my idle screws last I found the same issue, not much if any change in idle when they are adjusted.

I think I had turned down the main idle to almost a stumble and then was better able to hear a change.

I sinced my carbs last night but need to adjust the idle screws with the colortune and check the sinc again before a test ride, hopefully tonight.

The wife is getting a little irritated though. For weeks it seems I am either at work, in the cellar, garage, or on the computer.

[Jethro]

What position are the needles at now?

They are at the second from the top notch!!! I don't how the plugs are reading, becasue I don't care anymore. I am so sick of reading plugs. It pulls nice and hard to redline though, so that's a good thing. I'll really be excited to see what kind of results you get with that colortune.

For weeks it seems I am either at work, in the cellar, garage, or on the computer.

I hear ya! I probably say more things to my bike than my wife during the week! I better start trying to earn brownie points with her though, becasue wait until she sees me leaving every weekend at 7:30 am to go riding all day long!

[KEITH KRAUSE]

I've followed your problem for some time now. Somethings wrong and if it was my bike I would start at square one. I would verify these carbs are the correct carbs, then I'd verify all the jetting components, etc. I think someone's made changes to your carbs and it's completely screwed up logical re-jetting practice.
And as for your frustration and plug reading comments, what you say doesn't make sense. The plugs will absolutely tell you how the bike is running. Yes, there can be smaller issues the color won't show you, but the plugs WILL burn darker or even black/sooty if the mixture's too rich, and the plugs will burn whitish if the mixture's too lean. That's just the way it is. No exceptions. A perfectly clean plug is a lean plug, or fuel starved.

[Jethro]

I would verify these carbs are the correct carbs

They are definitely the right carbs. This bike isn't that far from showroom condition, and I can 100% confirm that the only changes from stock are the MAC 4-2-1 header and baffle, pod filters, a DJIII kit and a 530 chain conversion. Oh, and now my braided brake lines and saddle cover.

And as for your frustration and plug reading comments, what you say doesn't make sense. The plugs will absolutely tell you how the bike is running.

I know it seems impossible, but raising the needles 4 notches has made the plugs burn darker and more brown than the off-white glaze the tip had before! The proof is right there on the plugs!

A perfectly clean plug is a lean plug, or fuel starved.

I am no automotive engineer, but my theroy is that the plugs were staying cool by too much fuel, it's the only answer I can think of!

[KEITH KRAUSE]

You said you raised the needles 4 notches. Raising the needle richens the mixture. Unless you mean you raised the e-clip position, which would lower the needle and lean out the mixture.
If too much fuel enters the cylinder, the plug will stop firing. The spark will not jump the gap. It will take the path of least resistance and track down the wet insulator and go to ground. A wet plug means no combustion or very poor combustion.
Also, too much unburned fuel in the cylinder will also come out the pipe in the form of wet, black exhaust. Your mileage would be terrible if the bike ran at all.
I wish I knew what's up with your bike, but if you're happy with it now, that's good.

[Jethro]

I actually mean I raised the e-clip and lowered the needles- I'm a little dyslexic. Anyway, yes, it is running awesome right now. I still have an appointment with a Dyno machine where he will use an exhaust analyiser, then I'll know for sure if it's running right. I'm also interested in my max horsepower. Should be interesting.

Thanks for all your help everyone, I wouldn't have kept plugging away if you guys didn't help me out!