rich mixture

OP
OP
roby_59
Joined
Oct 21, 2016
Messages
43
Location
Rome (Italy)
Bike
ST 1100 ABS-TCS 1993
.

Adam's suggestion about the float heights is a good one; I was having some over-rich running and resetting the floats to exactly 7mm made for some improvement.
Have I to measure the float height with or without pressing the little spring in the float needle?
 

ST Gui

240Robert
Site Supporter
Joined
Sep 12, 2011
Messages
9,262
Location
SF-Oakland CA
Bike
ST1300, 2010
you don't mention what plugs you're running, but obviously they shouldn't be black
I was wondering about this myself. When I added K&N air filters to my 750-4 it ran much leaner than I liked and a little slower but un-silenced air sounded AWESOME!

I did a lot of playing with jets/needles/spacers to get the tip and electrode to chocolate brown and a very light shade of black on the outer ring of the plug (generally from idling).

So I wondered how "black" the plugs are in the OP's post because of the indication of running rich. Maybe he could comment on that.
 
Joined
Mar 20, 2016
Messages
1,201
Location
Auckland, New Zealand
Bike
2005 ST1300
STOC #
8901
Brant is confirming what Adam has said about checking the floats without depressing the spring.

When I did mine, I set the height at the far side of the float furthest from the needle, which would give the lowest fuel level.
 
OP
OP
roby_59
Joined
Oct 21, 2016
Messages
43
Location
Rome (Italy)
Bike
ST 1100 ABS-TCS 1993
I've completed the set-up:

pilot screws 1 turn in
float height 7 mm (was 8-9)
sinchronized the carbs

Result = Consumption increased and spark plugs like that:

View attachment 181503

:mad::mad:

.....I'm planning to re-set the float height to 9 mm !!
 
Joined
Mar 12, 2006
Messages
226
Location
Brewerton, NY
Bike
ST1100/ST1300
STOC #
949
Roby... The attachment doesn't work on my side.

One turn out is too lean. At a minimum with your ABS model, you'll need to be around 1 1/2 turns out. Setting your floats back up to 9mm will also be too lean. Leave them at 7mm.

At this point, I don't think there's anything wrong with your carburetors. Set them were they need to be and leave them alone. Something else is going on. Your trying to shut down the fuel and overcompensating by setting everything too lean. I'm thinking you have an ignition problem and the entire ignition system needs to be thoroughly checked over...
 
Joined
Jun 3, 2006
Messages
3,512
Location
British Columbia
Bike
2021 RE Meteor 350
Roby... The attachment doesn't work on my side.

One turn out is too lean. At a minimum with your ABS model, you'll need to be around 1 1/2 turns out. Setting your floats back up to 9mm will also be too lean. Leave them at 7mm.

At this point, I don't think there's anything wrong with your carburetors. Set them were they need to be and leave them alone. Something else is going on. Your trying to shut down the fuel and overcompensating by setting everything too lean. I'm thinking you have an ignition problem and the entire ignition system needs to be thoroughly checked over...
Attachment not working for me also.

Adam,

What about the fact that given the limited info we have from Roby about his measured fuel consumption and the type of riding involved, it appears he is getting a very similar km/ltr as most other 1100 owners, as I calculated in my previous post #18. From the beginning of this thread, it seems his only problem is the black plugs, which we still haven't seen an image of. We also don't know if he ever tried using a HONDA filter, rather than the K & N.
 
Joined
Mar 12, 2006
Messages
226
Location
Brewerton, NY
Bike
ST1100/ST1300
STOC #
949
Thats one of the things I dislike about forums. And you are correct. Limited and vague information... I see a guy from Italy, struggling with his bike. This is a US based site that uses English and US weights and measurements. I have no idea what he's getting for fuel economy and I'm not going to figure it out. I have to take his word on the switched air filters and that they are ok. Again, I agree with you about the K&N. It's either over oiled, or it's ok. If it's ok, then it will lean the bike out, coupled with very lean jetting from the factory. He said it's ok. I too would prefer that a new Honda filter be used. Thats what the bike is jetted for. He doesn't seem interested. So be it...

He apparently has sooty plugs and his milage is off a little. He wanted to deliberatly mess with the mixture screws and couldn't get the special tool. So, pull the carbs and set everything up properly while they're out. He still left the mixture screws at only one turn out and wants to put the floats back to 9mm because it's worse than when he started. If the carbs are set up properly(which they're not) and still getting black plugs, something else is going on. Possible weak ignition...

My '94 ABS and others that I've set up, run perfectly with a Honda air filter, idle mixture screws set at 1 7/8 turns, floats set at 7mm and .020" shims under the needles, with OEM jets. This is ideal for my area.
 
Joined
Mar 12, 2006
Messages
226
Location
Brewerton, NY
Bike
ST1100/ST1300
STOC #
949
Ok... It started to bother me about his fuel milage. I went to a conversion chart out on the net and did the math. I hope I'm correct here...
He says 14 kilometers per one litre of fuel used. Correct me if I'm wrong, but the chart works out to roughly 32mpg. Am I right? If this is the case, then this is horrible gas milage and I can believe he does have black plugs.
 
OP
OP
roby_59
Joined
Oct 21, 2016
Messages
43
Location
Rome (Italy)
Bike
ST 1100 ABS-TCS 1993
Roby... The attachment doesn't work on my side.

One turn out is too lean. At a minimum with your ABS model, you'll need to be around 1 1/2 turns out. Setting your floats back up to 9mm will also be too lean. Leave them at 7mm.

At this point, I don't think there's anything wrong with your carburetors. Set them were they need to be and leave them alone. Something else is going on. Your trying to shut down the fuel and overcompensating by setting everything too lean. I'm thinking you have an ignition problem and the entire ignition system needs to be thoroughly checked over...
the plugs in the attachment shows a light brown ceramic insulator plus a dark black matt carbon on the outher alloy ring. The dark ring is thicker and darker than before the setting. I didn't try the oem filter because is expensive and, anyway, k&n should guarantee higher air flow. Regarding the driving style, my test is performed on home to work drive: 20 km medium traffic in town (2000-3500 rpm) + 30 km highway (140 km/h) whithout any throttle excess.

P.S. I turned out the screws 1/2 not 1. The '/2' whas missed in typing
 
Last edited:
Joined
Jun 3, 2006
Messages
3,512
Location
British Columbia
Bike
2021 RE Meteor 350
Ok... It started to bother me about his fuel milage. I went to a conversion chart out on the net and did the math. I hope I'm correct here...
He says 14 kilometers per one litre of fuel used. Correct me if I'm wrong, but the chart works out to roughly 32mpg. Am I right? If this is the case, then this is horrible gas milage and I can believe he does have black plugs.
Your figuring is correct Adam, but, given the type of riding Roby now explains, it does fall into the same kind of mileage (roughly) that I get for around town, with a bit of highway riding. I can get 300 miles (500 km) out of a tank buzzing down an Interstate, but around town I'm looking to fill up around 250 miles (400 km).

Sounds like his plugs were OK to me, prior to messing with the carbs. Light brown on the insulator is what you want to see and some black on the negative side is quite normal. Now Roby is getting more carbon, with the idle screws only at 1/2 a turn out, according to his latest info.

Roby, put the carb settings back to Adam's specs, spend the extra dollars on a Honda filter and all SHOULD be good. Yes the Honda is a bit more money, but how often do you really need to change it? I usually get around 50,000 km (30,000 miles) out of one. Some people are anal about changing stuff out WAY before it needs to be done. FYI, the way to tell when an air filter is done is to shine a shop light through from the inside. When you see very little light passing through most of the filter, it is time to change it.
 
Joined
Mar 12, 2006
Messages
226
Location
Brewerton, NY
Bike
ST1100/ST1300
STOC #
949
Oh my... A 1/2 turn out and it's still too fat? You have almost shut off all the fuel on the idle and slow speed circuits. I have a sneaky suspicion that even if you were to put the Honda filter in, it would still make it worse. But that's just me. I hope I'm wrong. Just for piece of mind, it really doesn't take long to do fresh plugs, check all connections and do a complete resistance and voltage checks on the ignition system.... At least you'll know for sure it's not the ignition system.
 
Top Bottom