What are all possible causes of a lean condition?

[earlfor]

I just finished a test run of about 100 miles on my 1100 after rejetting.
Stock intake/airbox/filter and exhaust. 1197 kit. I'm buring medium brown on NGKD9EA plugs using #130 mains and the needles raised 3mm. Gas milage is about 40 mpg and oil temp guage on an 80 deg day reads 170F.

Before I rejetted and raised the needles, when I would get home and shut down the bike, It would heat/expansion crackle. It doesnt do that now.
Does yours have the expansion/.heat crackling sound after you shut it off?

On the float bowl vent T's between the 1,2 and the 3,4 carbs, I have shortened those hoses to 1" and they vent straight up to atomsphere.

The only thing I can think of at this point Jethro is that your boots may have cracks you cant see or find. I would remove the carbs and take some electrical tape and wrap each boot with a couple of layers of tape. If the boots are old enough to be porous, the electrical tape will temporarily seal the surface and you will at least know what the problem is.

With #160's in that sucker, you have to be getting too much air.

Do the throttle plates fully close in your carbs when the throttle is fully closed?

Earl

 

[Jethro]

once you're at, say a third throttle, does pulling the choke still affect anything or will the open throttle plates just ignore it?

I tried that. No change in pull or feel when I'm on the throttle.

Does yours have the expansion/.heat crackling sound after you shut it off?

Nope. No crackle or pinging or anything. And the block is only slightly too hot to touch, although I haven't seen anything warmer than 50F here. Oil temp gauge reads 160 most all the time.

The only thing I can think of at this point Jethro is that your boots may have cracks you cant see or find.

Boots and clamps are brandy new OEM units. Pretty sure there isn't a single intake leak as I doused the boots with the most flammable fluid I had in the garage- crab cleaner.

With #160's in that sucker, you have to be getting too much air.

The 160's make the bike run like crap, but the plugs don't get any darker...

Could it be possible that my bike is so efficient that I get a perfect burn? I've ridden 300 miles on the bike and the plugs look like they just came out of the box, except for an off-white glaze on the very tip of the plug.

 

[snowbeard]

sorry Jethro, mine was a theoretical question of should pulling the choke at a third throttle make any difference? earl? still there? :wink:

 

[AOD]

Could it be possible that my bike is so efficient that I get a perfect burn? I've ridden 300 miles on the bike and the plugs look like they just came out of the box, except for an off-white glaze on the very tip of the plug.

Obviously not if you have a flat spot at 6000 RPM. At 6K you're running off the needle and main (main if WOT).

Have you done a plug check at 6000 RPM where it flattens out, to see wha the plugs read vs. say 9000 RPM where you say it pulls fine?

Earl, why are you running a '9' plug? I believe that's the hotter heat range plug...

~Adam

 

[Jethro]

sorry Jethro, mine was a theoretical question of should pulling the choke at a third throttle make any difference? earl? still there?

Ahh, yes. If you find that applying a little choke under hard throttle makes the bike pull harder then you may have an intake leak. What happens is that the choke cuts off some air and enrichens the fuel mix. It brings the mix back to where you should be if you didn't have an intake leak. Theoretically.

 

[snowbeard]

well at least your post helps someone, eh? good to know that if I still had an intake leak I could tell by pulling the choke.

now what does it mean that with throttle it does nothing from a choke, but at idle it revs up and then dies off unless I let go...?? I'm thinking there maybe something blocked up in my idle. I see in the carb cleaning guide that there is a choke circuit, but what holes/jets are responsible for the idle?

thanks for letting me horn in some on your thread J!! :wink:

 

[Anonymous]

...I doused the boots with the most flammable fluid I had in the garage- crab cleaner.

Gee, where I come from we usually just call crab cleaner "beer."

I'm not normally one to make a joke at people's typos, but I got a kick out of that.

Well man, I'll be interested to hear what the dyno testing tells you. As far as holing a piston, I think plug readings alone shouldn't inspire that fear in you. Your engine is running nice and cool, and so far you haven't mentioned pinging. I'd say happy riding man.

 

[earlfor]

In NGK, a 9 is a colder plug than an 8. In Champion or AC, I beleive it is the opposite. Dont know for sure though, I dont use those two "off brands" LOL

Stock plug for an 1150 is a D9EA, so why not the same plug for an 1197?

Earl

Earl, why are you running a '9' plug? I believe that's the hotter heat range plug...

~Adam

 

[Clone]

My yamaha runs a little lean and the bike warms up really fast. I've never checked the plug. I take it to a shop and have them sniff the exhuast twice a year. The report tells me the proper range. The mechanic tells me it's ok so I leave it. It passes the epa inspection this way without any problems.
I think you should have the exhaust analyzed.
like the other guys said, I don't think your bike runs lean.

 

[pano]

Jethro,

If the weather and all else works out for the 9th I will arrive early and as I said in another post we can take a look with my newly aquired colortune We could also do a quick carb swap if that is something you want to try. I wonder there is something whacked with you needle set-up.

Have you tried the carbs from your 81? I forgot you had that.

 

[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!