Is this lean or rich?

[lee1rbc]

OK, I have installed on my 600 the following.

D&D full exhaust, K&N using the larger donut hole, ignition adv., and a Dyno jet Kit.

I am using a 116 main jet and that seems to work the best. I also bumped the needle up one setting; before it would fall on its face if I hit it at 5k. Now it pulls strong from 3k all the way to red. I still notice that if I open the throttle all the way between 4k to 6k and then back off the throttle a hair it will pull a little stronger, but I am afraid that if I go richer ,when its 90deg outside it will run like a dog. Anyway.....

I am finally working on the idle mixture. When I go to start the bike in the morning it kind of sputters to a start and the choke doesn't do a thing. When I blip the throttle after idling for 20seconds it is not crisp, but then I hit it the second time and its better. When the bike is warmed up and I take off from a light, it will bog for a moment unless I work the throttle, after 2k I am fine. Also when I blip the throttle it will drop to 2k and the slowly make its way to idle. I currently have the idle screws at 2 1/2 full screws out or (5 half turns out). Am I running rich? or lean?

[BarMatt80]

well i will take a wack at this, but someone will step in and tell you exactly what is going on. First off if the throttle hangs and then drops to the right idle then it is lean. Try richening it up in 1/4 to 1/2 turn increments. I was having the problem once the bike gets hot it would fall on its face unless i got ingenious with the throttle. I gave up and took it to the guy at the dyno and he said my needles were way to rich. And they were on 3rd clip, so i assume he moved them to 2nd clip(not sure yet haven't got bike back yet). So maybe try richening up your idle and dropping your needle, but wait for someone more informative to tell you what is up.

Oh one thing, what do your plugs look like?

[lee1rbc]

ok, I pulled a plug and there is black soot around the rim. And a little black soot on the tip. This is after letting it idle for 10 minutes.

[md86]

Well , I'd bet its a little lean on bottom . Letting it idle for a while WILL make that black soot form , so you can't really go by THAT . Seen the tuning guide yet ? If not .... http://www.factorypro.com/tech/carbt...m_engines.html

[lee1rbc]

Thanks guys for the feedback. I have been studying the tuning guide page for the past two hours and has been a real helper. For kicks I thought I would take Your advice Barmatt80. I have pulled the carbs and set the idle mix from 2 1/2 turns to 3. I have also dropped the needle back down one step. Ill let you know the results tomorrow.

[lee1rbc]

OK, on my needle I went from #4 from the top to #3 from the top (leaner)
and I went from 2 1/2 turns idle to 3 turns idle (richer).

This took care of my stumble off the line issue and really improved my idle. The bike is much quieter part throttle and cruise. But I still had that "fall on your face" issue when taking off full throttle when cold,better when warm but still there.
So I went from a 116 main to 120 main. I just road with this setting for an hour and NO FLAT SPOT! I feel I am so close with this setting, so next step is the dyno. I do notice now when down shifting at higher rpms and letting the motor slow the bike down I hear very light popping in the exhaust. Thanks for the feedback.

[lee1rbc]

I went to the Dyno today and WOW am I running lean. I will try to scan my dyno sheet and post it later tonight. My idle is 17.5 to 1, from 4k to 7k its off the chart (above 18 to 1.) From 8k to redline it settles in at 15.5 to 1.
The mechanic said everythings lean, and that I should do the following.
1. Turn idle screws from 3 turns to 3 1/2.
2. Step the needle up one step richer.
3. Go from a 120 main jet to a 130 main jet.

Oh yeh, my HP was 70 and trq 37.

[BarMatt80]

well knowledge is a good thing and you know where to go with it. What kind of k&n are you running? YOu could almost simply fix yoru problems if you are using teh large donut and go to the small donut, but that is soemthing you will have to mess with and figure out with the dyno. good luck with it, i just got mine dynoed but no read out on hp or my fuel curve(dude didn't have a printer). but mine was so rich it wouldn't read.

[Anonymous]

I went to the Dyno today and WOW am I running lean. I will try to scan my dyno sheet and post it later tonight. My idle is 17.5 to 1, from 4k to 7k its off the chart (above 18 to 1.) From 8k to redline it settles in at 15.5 to 1.
The mechanic said everythings lean, and that I should do the following.
1. Turn idle screws from 3 turns to 3 1/2.
2. Step the needle up one step richer.
3. Go from a 120 main jet to a 130 main jet.

Oh yeh, my HP was 70 and trq 37.

i would go to 3.5 turn go to 4th notch on the needles and leave it be 15.5 aint that far off from theoretic perfect of 14.7 to1 but also raising the needl will add a lil bit of fuel to the top end also not a whole lot but possibly enough to make the mixture go to 15to1 and 130 mains from 120 is a huuuuuuuuuuuuuuuuuuuge jump so i would advise against it

[The CyberPoet]

Your torque numbers are really low, IMHO, and the HP numbers aren't bad but aren't all that impressive for an '05 with an aftermarket exhaust+jetkit+K&N filter. I get 43 lb-ft torque and 70.9 HP with the stock airbox & filter, Ivan's Jetkit, 5 degree advancer, and a Suzuki Kat 750 header slapped on my '01 Kat 600. No race oils, no trick anything -- and that was with a chain & sprockets that had 8500 miles on them already...

Generally, ideal "Performance" tuning you want to hit 14.6:1 air-fuel ratio (AFR) at idle, and 13.6 - 13.0:1 above about 3k.

For ideal "Fuel Economy & touring" tuning you want to hit 14.7-14.8 AFR at idle, and 14.2 to 14.5 everywhere else.

Stoichiometric air-fuel ratio (the point at which every single bit of fuel is matched perfectly to the oxygen content of the air in the cylinder, resulting in the cleanest possible burn) is nominally 14.7:1, but that is valid only for absolutely perfect test fuel (gasoline containing only n-heptane and iso-octane). Most fuels are composed of a combination of heptane, octane, other length -tanes, plus additives, and the typical stoichiometric air rate for most fuels is around 14.5:1 (as low as 14.2:1 for fuels containing MTBE or ethanol/methanol, such as winter blends for pollution-control regions -- which is why some people have a real bear of time getting their Kat started in the cold).

Thus, although you might consider 14.5 as "a hair rich" by the book, it may actually be a bit lean for your particular area and fuel. If you hit the dyno, make sure that you have fresh fuel of the brand and octane that you usually tank with, and always get a dyno reading when the specialty winter fuels have already been shelved for the summer if you do most of your riding during the summer... Also make sure you haven't added any additives to the fuel (such as Techron, Seafoam, etc) that may skew the numbers...

Running richer above idle improves throttle response, torque and power up to about 90% through the primary torque range*, as well as lets the engine run cooler, although at the price of slightly increased carbon build-up and excess pollution from partially unburnt fuel being ejected into the exhaust.
* although running that extra point rich loses something in the absolute top-end, i.e. above 9500 RPM on the 98+ Kats

I run my bike at 14.6:1 at idle and 13.6 to 12.9:1 in the 3k-10k RPM range (I wish I could figure out how to get it to go back close to stoichiometric [14.5:1] above 9k RPM, but I can't have it both ways).

Using the smaller donut will increase the vacuum levels at the carbs and draw more fuel through-out the RPM range, letting you get away with smaller jetting and giving you better fueling everywhere except the very top of the RPM range again -- because higher vacuum means the air is moving faster through the carbs, improving the effectiveness of the mixing, and improving the cylinder loading.

Cheers,
=-= The CyberPoet

[lee1rbc]

Wow, great stuff guys. I am still trying to get the dyno sheet scanned, I think that will give some good insight.

He did two runs, the first run I was 16.2 to 1 at 10k rpms, 67hp
the second run in third gear was 15.6 to 1 at 10k rpms. 70hp
OK what I am going to do is adjust the needle, and idle screw and then dyno again before anything else. Also I think I will bring my smaller donut hole and see what the difference is. Also I am going to put the stock springs back in.

[lee1rbc]

OK, for kicks I just went out and put the smaller hole in the air filter and took it for a spin. YEEEHAAA, I feel like I gain 50hp at every rpm!

[BarMatt80]

just curious...how much is each run on the dyno? and how much is hourly rate to dyno tune? I just ask because the guy that did mine was $35 for two runs, just for readings, but it was $40 an hour for dyno tuned, so you could have it fixed then just for a couple more bucks.

[lee1rbc]

The place I went to charges $35 for a base pull. And $75 for a full dignosis.

[The CyberPoet]

In my area, $20 - $30 is standard for a dyno run, and $100 is what you should expect to pay for a dyno tune if the fairings are already off when you show up (including him pulling the carbs & changing jets if necessary). Naturally, this assumes that you have the jets he needs (or he does) and that he can hit the right jetting (i.e. - that your config isn't so off-base that it's impossible to jet right with pretty much any combo).

Cheers,
=-= The CyberPoet