Pilot Mixture Settings

[optimaldave]

Hello All,

I recently got a 97 bandit 1200 which had been sitting for a while and wouldn't run right. So I pulled the carbs and a suzuki tech I know cleaned them out for me but he forgot to count the rotations for the pilot screws... Mods consist of K&N filter, hindle silencer and mid. If anyone has this setup can you tell me where you ended up for rotations of the pilot screws? I set them at three and it is popping but more sounds like it is popping rich (almost like a gurgling) then a "backfire" of lean popping. But I am only an apprentice so my ears are by no means good at determining these things.
This bike was jetted properly before (113 mains, not sure of the pilots) so it is just the pilot screw that I need to setup. I have heard that 2.25 is stock, and some people on a stage two are out at 4+ so I am really not sure if I am likely rich or lean...

Cheers
Dave

[rider123]

I don't know if this helps but Fastlarry Bandit FAQ says from 2 to 3 for stock setup and 2.5 to 3.25 for a stage 1 with a 2" hole. Sorry I got a 2G Bandit. You could always start out a 2.25 and do a 1/4 of a turn out at a time and see if that gets you there. I assuming from the strange jet size 113, your airbox is closed up and your using the factory hole, with no extra holes drilled in there.

You'll know your rich when you lightly blip the throttle and the rpm dive a bit below the set idle then recover. If your lean when you blip the throttle it will go slightly higher than idle then set back down. Also the very tip of the plug(not the porcelin but the metal bit connected to it) will be blacker than normal and you may see some black deposits on the ground strap. Thats the ring around the bottom of the plug. At 3 turns out do you have black smoke come out when you rev the throttle?

[optimaldave]

I don't know if this helps but Fastlarry Bandit FAQ says from 2 to 3 for stock setup and 2.5 to 3.25 for a stage 1 with a 2" hole. Sorry I got a 2G Bandit. You could always start out a 2.25 and do a 1/4 of a turn out at a time and see if that gets you there. I assuming from the strange jet size 113, your airbox is closed up and your using the factory hole, with no extra holes drilled in there.

You'll know your rich when you blip the throttle and the rpm dive a bit below the set idle then recover. If your lean when you blip the throttle it will go slightly higher than idle then set back down. Also the very tip of the plug(not the porcelin but the metal bit connected to it) will be blacker than normal and you may see some black deposits on the ground strap. Thats the ring around the bottom of the plug. At 3 turns out do you have black smoke come out when you rev the throttle?

Thanks for that, I remembered reading something about how idle acted rich and lean but couldn't remember but now I can play with it.
The airbox had a hole drilled in it but was taped over. I have considered pulling the tape off but it would assumedly cause more issues as the bike is jetted with it taped over.
no black smoke, but it requires very little choke to run cold which is also why I suspect rich.
Will play with the throttle and mix as my 90 degree tool came in today, will then check the plugs.

May also just cave and buy a colortune as my old one is for a B plug, but I can see it being a pain to get it into cyls 2/3 so I will try it the old fashioned way first.

Cheers
Dave

[rider123]

Here is fast larry's little chart. I image if you take the tape off and open up the hole your going to need larger mainjets for sure.

http://www.portablepct.com/fastlarry/banditfaq.htm#fuel_system

[optimaldave]

Here is fast larry's little chart. I image if you take the tape off and open up the hole your going to need larger mainjets for sure.

http://www.portablepct.com/fastlarry/banditfaq.htm#fuel_system

Ok, being rich does make sense then as I am pretty much stock with aftermarket pipe. So I will do the throttle blip testing and start working down (lean)

Cheers
Dave

[rider123]

Well you do have a K&N on there so it will flow more than stock. If 2.25 is the stock setting I would try 2.5 or something and work up or down from there.

[optimaldave]

Well you do have a K&N on there so it will flow more than stock. If 2.25 is the stock setting I would try 2.5 or something and work up or down from there.

Yeah, I am at three so I'm going to start working down from there but the tool I got from motion pro will need some modification as the case appears to bottom out before the shank can hit the slot... Kinda miss my hitachi's with the pilots on the top of the carb :p

Cheers
Dave

[rider123]

If you want you can just use a bit from a screwdriver and a cheap dental mirror from a drug store. That's what I've been using, not as fancy as a speific tool but it works and is cheap.

What I did was turn mine to the recomended settings from Holeshot then rode it for a good 20 mins. There is no point in riding less than that. If the bike is a little jerky/not smooth at very small throttle inputs it probably needs a bit more. Usually a 1/4 turn out will be enough. Also you can ride it around for 20 mins so its nice and warmed up then rest for 5 mins or so to let the engine cool a little bit. If you start the bike back up and it is jerky/not smooth it tells you that it probably needs that 1/4 turn out as well. The reason for this is as the engine cools, if the pilot screws are a little lean it will aggrivate it just enough for you to tell that they need just a squirt more. You will also notice if you turn out the mixture screws and the idle increases slightly you did the right thing. If it drops you went too far.

[optimaldave]

If you want you can just use a bit from a screwdriver and a cheap dental mirror from a drug store. That's what I've been using, not as fancy as a speific tool but it works and is cheap.

What I did was turn mine to the recomended settings from Holeshot then rode it for a good 20 mins. There is no point in riding less than that. If the bike is a little jerky/not smooth at very small throttle inputs it probably needs a bit more. Usually a 1/4 turn out will be enough. Also you can ride it around for 20 mins so its nice and warmed up then rest for 5 mins or so to let the engine cool a little bit. If you start the bike back up and it is jerky/not smooth it tells you that it probably needs that 1/4 turn out as well. The reason for this is as the engine cools, if the pilot screws are a little lean it will aggrivate it just enough for you to tell that they need just a squirt more. You will also notice if you turn out the mixture screws and the idle increases slightly you did the right thing. If it drops you went too far.

The driver bit works really well, thanks.

My problem for the diagnosis is that the bike runs beautifully, throttle snaps are crisp, nothing hangs or sputters. The only thing to indicate that it is off is a slight bit of popping from the exhaust on decel, mostly below 4000RPM. So I turned them in a bit and it got worse, turned them out a bit and it was quite a bit better, turned them out some more and it got worse, so I have set them to the best I found and I think I may leave them as such for now and live with the popping until I feel like tinkering vs riding. May take a stab at the idle increase method though. I also think I am going to sync them as I know that can solve many of these sorts of issues.

Cheers
Dave

[rider123]

A little popping is normal. I still have a bit of popping. If you have the PAIR emissions bullshit on there(like mine, plan to remove) it will pop even if you are too rich on the pilots. Don't worry about it, you probably have it right in the middle setting.

[optimaldave]

A little popping is normal. I still have a bit of popping. If you have the PAIR emissions bullshit on there(like mine, plan to remove) it will pop even if you are too rich on the pilots. Don't worry about it, you probably have it right in the middle setting.

Cool, then I won't worry about it for now.

Thanks for your help

Dave