Author Topic: Need help adjusting air/fuel mixture pilots  (Read 34315 times)

Offline IcyChaos

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Need help adjusting air/fuel mixture pilots
« on: May 16, 2006, 12:37:01 AM »
My 2000 Bandit 1200 1G has some issue's with its pilot screws. I have a terribly arge deadzone from 4500 - 5500. after visiting a mechanic he adjusted the pilot screws and it cleared up (mostly)  but he said a good idle is 1K rpm's.  I disagree, my bike takes off like crap at 1000 RPM's and I prefer 1200 - 1300 idle. Well if I move the idle the deadzone is huge again.

I bought a nice pilot screw adjustment tool today and fiddled around with it going by the haynes manual. It says set the idle to where you want, screw in all the pilots, then back 1 out until you get a hi steady idle,  re-adjust idle, and then back all screw out to match.  As soon as I turned all the screws in the bike died. So I don't know how to get an accurate reading. I believe my screws are at least 3 full turns out.

Maybe someone can explain this better to me, so I can finally adjust this perfectly. Im sick of my idle RPM needle bouncing up/down and the popping, or dead zone im experiencing.  My screws are all messed up, so I need to fix this as if I don't know what they should be at. Bike has a stage 2 , yoshi bolt-on and and K&N pods.

Offline mike

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Need help adjusting air/fuel mixture pilots
« Reply #1 on: May 16, 2006, 01:48:46 AM »
Read up for a little research to fully understand what you're dealing with....

Carb Tuning FAQ
http://www.factorypro.com/tech/carbtune,CV,high_rpm_engines.html

Offline IcyChaos

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Need help adjusting air/fuel mixture pilots
« Reply #2 on: May 16, 2006, 02:13:39 AM »
Thanks mike, I read up on your homework assignment. Helped me understand how to see too rich/lean.

When everything says 3 turns out 4 turns out etc. is that from fully seated in?? Its hard for mr to tell if I have the screws all the way in without going too tight.

regardless, I guess I'll just play with it,  turn them all in, then out 3.5 turns and try it out. then just keep adjusting till all is well..

Offline Daytona

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Re: Need help adjusting air/fuel mixture pilots
« Reply #3 on: May 16, 2006, 02:20:28 AM »
Quote
="IcyChaos"]My 2000 Bandit 1200 1G has some issue's with its pilot screws. I have a terribly arge deadzone from 4500 - 5500. after visiting a mechanic he adjusted the pilot screws and it cleared up (mostly)  but he said a good idle is 1K rpm's.  I disagree, my bike takes off like crap at 1000 RPM's and I prefer 1200 - 1300 idle. Well if I move the idle the deadzone is huge again.

I bought a nice pilot screw adjustment tool today and fiddled around with it going by the haynes manual. It says set the idle to where you want, screw in all the pilots, then back 1 out until you get a hi steady idle,  re-adjust idle, and then back all screw out to match.  As soon as I turned all the screws in the bike died. So I don't know how to get an accurate reading. I believe my screws are at least 3 full turns out.

Maybe someone can explain this better to me, so I can finally adjust this perfectly. Im sick of my idle RPM needle bouncing up/down and the popping, or dead zone im experiencing.  My screws are all messed up, so I need to fix this as if I don't know what they should be at. Bike has a stage 2 , yoshi bolt-on and and K&N pods.
You need to turn your idle adj too about 1500 rpm and then adj the primary fuel screws. adj all 4 to say your 3 turns out and go in till rpm drops and back out till its @ the sweet spot' adj rpm back to your liking. Now with that said if your carbs aren't rite or linkage needs sync ed this adj won't be worth the time! A sync is magic IMOP. :beers:

Offline IcyChaos

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Re: Need help adjusting air/fuel mixture pilots
« Reply #4 on: May 16, 2006, 10:33:04 PM »
Quote
Daytona: You need to turn your idle adj too about 1500 rpm and then adj the primary fuel screws. adj all 4 to say your 3 turns out and go in till rpm drops and back out till its @ the sweet spot' adj rpm back to your liking. Now with that said if your carbs aren't rite or linkage needs sync ed this adj won't be worth the time! A sync is magic IMOP. :beers:


Thanks so much. This should do the trick, I had valves adjusted and carb sync kinda recently, so hopefully this will work. I'll screw with it tomorrow.

Offline IcyChaos

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Re: Need help adjusting air/fuel mixture pilots
« Reply #5 on: May 16, 2006, 11:55:33 PM »
How can you tell the sweet spot???  Is thta where the ROM gauge stops fluctiating at all?? then drop to 1200 RPM?

Offline Daytona

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Need help adjusting air/fuel mixture pilots
« Reply #6 on: May 17, 2006, 02:08:08 AM »
Go out with them until it is smooth (do the 2 inside before the eng gets hot) on ea one as you go, then adj the idle to your liking. My B12 worked just fine @ 1000 idle and didn't clunk in to gear like it will at higher. The real tale is when blipped it should come back to the setting but not below! If it takes a bit to come down the primary's are open too much or the enrichner's maybe seeping some. Make sure all the enrichner plungers are in all the way. If carb sync was done with these settings off it wasn't worth the time it took! and will need to be redone. After your done make sure all your header tubes are about the same temp. The old spit on the finger works unless you have a lazer temp gun!  :beers:

Offline smooth operator

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Need help adjusting air/fuel mixture pilots
« Reply #7 on: May 17, 2006, 07:32:30 AM »
Make sure that when you turn in the mixture screws that you don't go too tight! Soon as they bottom,stop,so you don't damage anything.What size piolots are you running?If your 3 or more turns out and still getting alot of popping you may be too lean in your low idle.And might have to go up a size.

Offline rider123

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Need help adjusting air/fuel mixture pilots
« Reply #8 on: May 19, 2006, 04:03:34 PM »
Actually to be honest the rpm range you are experiencing the "dead zone" in is more a matter of needle position than pilot adjustment. While adjusting the pilots does help some(they overlap a bit) it will make you too rich at idle/off idle and hence the poor off idle mushy response. I would help this by putting up the idle rpm to around 1200 or so. Can you tell us more about what's on your bike? Do you have a jet kit? Do you have an aftermarket pipe? How many turns out are your mixture screws? I wouldn't just willy nilly start fooling around with the mixture screws just yet. If you want to fiddle with them a bit mark where they are now so you can go back to where they were before if it all goes to hell.

If possible can you tell us:

Jet kit if any
main jet size
pilot jet size
aftermarket exhaust
turns out from lightly seated on mixture screws
airbox mods? snorkle in or out?

Sometimes if you removed your snorkle popping it back in reduces the rpm level you are talking about's dead spot. It would help alot if you could give us some more info. Do you have excessive popping on deacceleration? Some is ok, but if it sounds like gunshots you are a probably lean on the pilots.

Also it's best to wait untill you're full hot(at least 20 min riding)to start adjusting the mixture screws. If you adjust them when they are cold they will be super rich when the bike heats up. Since you have a tool this is no problem. On my 2G bike I just used a dis-combobulated 1 inch long small flathead hex bit from a screwdriver and it works find without too much burning action. The best way to adjust the pilots if you can find the "sweet spot" is to find the sweet spot then give a teeny bit more out to richen it up slightly as when you are at idle it's fine but once the bike moves forward it's going to need a little bit of extra juice(not a lot maybe 1/15th of a turn out) to "get over the hump" and on to the main jets. If you have any doubts on whether to go rich or lean try and stay on the rich side of the equation to be safe.


Big EDIT:

Opps I did see you gave us a bit of info at the end of your post. If you have a stage 2 I would start the pilots at 3 turns out and go from there. No idea on the mains or pilots though? I'm assuming that you have adjustable needles though as hopefully(we've seen some rough shit) they actually jetted the bike to match the can and K&N pods(you'd be suprised). What I would do in your situation is get the pilots to where they should be, forget about the dead spot at this point. Get the idle and off idle in the ballpark so that it's not too crazy. Then I would richen up the needles one notch and see if that gets rid of the dead spot. You can fiddle around with the pilots forever but the rpm level you are talking about is more based on needle position. If one step richer is too much you may have to go back and shim up a half step.


Good luck! Try to do things in little steps so you don't overwhelm yourself with too many changes.


Here is a bad ASCII version of an adjustable needle:


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-
-<---If you are here on your needles go
-<.....to here to richen up the mixture in the mid range rpm
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I
I
I
I
I
I
I
I
I
V
2005 Bandit 1200, Modified Holeshot Stage 1 with 17.5 pilots 2.75 turns out, and 110 mains 5 shims. Muzzy Slip on w/mid-pipe, stock filter. 1.5" hole in the airbox lid.

Offline IcyChaos

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Need help adjusting air/fuel mixture pilots
« Reply #9 on: May 20, 2006, 04:55:23 AM »
I've never messed with the jetting or carbs or needles.  how involved is this process???

honestly I bought the bike used. According to him, it has a stage 2 jet, and a full exhaust. I believe it only has a bolt-on yoshi, not a full one, but Im not 100% sure on how to tell.
It does have K&N Pods, and I just added the holeshot 5% timing advancer.

I am at 4 turns out now, and its running pretty good. no more dead zone, or not much of one, but has some popping on decel.

Offline smooth operator

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Need help adjusting air/fuel mixture pilots
« Reply #10 on: May 20, 2006, 07:17:10 AM »
4 full turns out seems like alot to me,I'd be worried about having them back out and loosing one. Maybe I'm wrong(its been known to happen befor)but if your that far out,I think your trying to make up for the wrong piolt size by over compsating with the mixture screws.(but I'm just a tilesetter)

Offline smooth operator

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Need help adjusting air/fuel mixture pilots
« Reply #11 on: May 20, 2006, 07:27:06 AM »
Befor changing jets,check and see what knotch your needles are on.Move the clips down a knotch to raise the needles and start  2 3/4 turns out. (Again this is the advise of a dumb tilesetter) But it doesn't cost anything but time.

Offline Daytona

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Need help adjusting air/fuel mixture pilots
« Reply #12 on: May 20, 2006, 08:46:19 AM »
Quote
="smooth operator"]Befor changing jets,check and see what knotch your needles are on.Move the clips down a knotch to raise the needles and start  2 3/4 turns out. (Again this is the advise of a dumb tilesetter) But it doesn't cost anything but time.
Hey set tile and stop playin mechanic!!! Smoothey whats up!!!! :bigok: Hey IcyChaos if you have it running ok! just make sure the needles don't back out AND RIDE IT LIKE YOU STOLE IT!!! After stage two ing etc etc these things loose the stock drivability to some extent. It sounds like if you don't know the diff between a stock header, or a bolt on aftermarket you may not want to mess with this stuff! U need to live closer to a chum like Smooth operator! or such to get started. Don't worry about minor popping they all do it with aftermarket exhausts. :beers:  :beers:  :beers:  :motorsmile:  :motorsmile:

Offline Daytona

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Need help adjusting air/fuel mixture pilots
« Reply #13 on: May 20, 2006, 08:56:03 AM »
Ok this cook is going to stop stirring in this pot! Getting into carbs!! while we all have to start some where' this can be a can of worms and never turns out rite unless you are swuft in this sort of thing. Take it to a shop and get some other opinions!   :beers:  :beers:  :bigok:

Offline IcyChaos

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Need help adjusting air/fuel mixture pilots
« Reply #14 on: May 21, 2006, 04:20:50 AM »
Quote from: Daytona
Quote
="smooth operator"]Befor changing jets,check and see what knotch your needles are on.Move the clips down a knotch to raise the needles and start  2 3/4 turns out. (Again this is the advise of a dumb tilesetter) But it doesn't cost anything but time.
Hey set tile and stop playin mechanic!!! Smoothey whats up!!!! :bigok: Hey IcyChaos if you have it running ok! just make sure the needles don't back out AND RIDE IT LIKE YOU STOLE IT!!! After stage two ing etc etc these things loose the stock drivability to some extent. It sounds like if you don't know the diff between a stock header, or a bolt on aftermarket you may not want to mess with this stuff! U need to live closer to a chum like Smooth operator! or such to get started. Don't worry about minor popping they all do it with aftermarket exhausts. :beers:  :beers:  :beers:  :motorsmile:  :motorsmile:


In my defense, I was told its a full system. But since all the pipes are gold, like stock tends to do, minus the muffler(yoshi) I think its stock.  so then I start looking into full yoshi system pics, some show 3 to 2 to 1, and I've seen some that look the exact same as mine, 4 to 1 yoshi full system, stainless steel.  Does the full yoshi system turn gold like the stock?

so until I actually see a Full yoshi system on a 1G bandit, I can't know for sure, because some of the pics I've seen match what I have, or look exactly like stock.

Also why would My bike have a stage 2 with a bolt on? wouldn't it be better to have stage 1 with bolt on and K&N pods?  

Im pretty sure its a stage 2 jetting because I have a dynojet coupon and a dyno test from the previous owner.


As for delving into the bike further, Im ready. I read the haynes manual all the time, just for the hell of it. Im learning one thing at a time, have a front wheel stand and rear wheel stand, but I haven't done much except for changing my oil, adjusting chain slack / taking off rear plastics to replace relay / installed timing advancer / cleaning / torque bolts etc.

Eitherway, When messing with the pilots, Its running pretty well 4 turns out. when screwing around I have turned them out 6 or more turns, flush with the hole, but even at 4 turns out, its hardly half way out of the hole.

Dale Walker said go 3.5 to 4 turns out, so maybe jet 2 goes farther out then jet 1?? I don't know..

Regardless every mechanic I've taken my bike to has done something wrong. I almost need to know what Im supposed to do, just to make sure they do it correctly.  for instance, I had valve adjustment and carb synch with plugs done.  he didn't bother touching the pilot screws, or have me clean the air filters beforehand. shouldn't a carb synch be done in conjunction with these things?

another mechanic installed a new chain that wore very quick because he didn't know what slack to use, and sold me dirt bike chain oil.

finally 3rd mechanic just did my front forks and valves, the preload screws are all the way out, sticking very far out not flush like it used to be at full pre-load, is this normal?.   Also didn't bother having me sit on it for measurements etc. to cut spacers. Im not sure if this is something that should be done when you get racetech springs and valves installed.

eitherway I've given up on bike mechanics. Im slowly learning enough to do stuff on my own, but I do need guidance, since none of my friends have any bikes similar to mine.