1980LG Carbs

[redbird1]

Hi All, I have been followint this forum for a while, Some Questions on carb issues that I have if someone can help?
Here is my set-up and plan.....
I "aquired" the bike last fall from someone that I work with, when he purchased it the year before it had a stock exhaust the air box had been removed and 4 K&N's were on it. The bike had a leaky NO.1 carb. He chopped the exhaust partially off to install a pair of 1993 sportster mufflers, and told me that he had the carbs apart to stop the leak but it didn't. He ran the bike all last summer with the leak. no jetting was done by him.
Ok now I have the bike, I purchased a 4pack of carb kits from e-bay, I have pulled the carbs apart and installed the kits for the most part,
Here are the issuse and Q's On the bike were 115 main jets on all 4 carbs, I didn't change them as I got in the kits 110's and I don't know what stock jets for that model were ( does anyone know that one?)
The pilot jets were 42.5's on the bike and in the kits as well, I put the new ones in, I replaced the little filter backed things behind the floats on all 4 carbs and the needle thingy's on all floats as well. This should stop the leaking on 1 and prevent the rest from starting soon.
Lastly, on the outside of the carb there is a removable needle assembly-I have all 4 but replaced just one as I do not know what the bench setting is on those-or what they are really for? Carb no. 2 was 3 full turns out so I replaced the no. 1 and gave it 3 turns out for good luck I'd have to ask on that one right?
I will be installing a Jardine 4into1 that I already have shortly enough so jetting...... I just don't know and I did find the pointer already posted on jetting recomendations, it is great but I don't know what has already been done if anything.
These aren't the same carbs as are on my FZR600 that is for sure, I didn't change the float height at all so thast you know, any help out there?
Thanks, Dave

[mro]

I've got 110 mains on my LG carbs.
Some may have 115's in the center pair.

float height, 23mm
(not a bad idea to bench test carbs for float valve/needle leaking)

On the engine side of carbs, top center are the pilot screws
(can see em if factory plug has been removed)

Generally set to 1 1/4 turns out from "lightly seated" for inital adjustment.
I like to vac synk the carbs, then tune the pilots and then check the synk again.


mro

[redbird1]

And it runs but...

Thank you mro for that advise, I will be working on a sync set-up this week and I'll be having it on the road shortly as well.
I put it together a few minutes ago and did a plug check before I keyed it up, They were white on the electrodes and tips as well as had carbon residue on the thread area-kinda scarrrrry that this guy ran it all last season that way. It didn't sound bad with the Sporty pipes on there but I'm apt to install the 4into1 on it this week to try and quiet the thing.
So This leads me on 2 things, first There is a backfire sometimes when gassing it sitting there in neutral, This means the sync is out?
Second I have the 4 individule air filters and will have a 4 in 1
My understanding is that will be an increase from my 115's to 125's and from 42.5 to 45.0
That would be Upstate NY math, (4 sizes the mains and 1 on the pilots) as per that cool jetting guideline section?
By the way A bunch of us (15 bikes) rode up to lake Placid today, Weather was perfect and the 1100 now starts.....

[TopCatGr58]

Hey Redbird,

These bikes/engines run fairly well LEAN, they were set up that way in the later years by Yamaha for Emissions.

The stock value you would want to start with is the 110's. I have Indy filters, 4-1 pipes and run 117.5's, and the stock Pilot jets, just have the screws out an extra turn, good plug color, easy starts and response. The guide mentions subtracting 1 size when you have a combo of mods, like 4-1 and Indy filters.

The black carbon around the base of the plug with white insulator is decent plug condition, these newer cleaner unleaded fuels don't necessarily give as good of coloring to the insulators like the old gas of the 70's. The backfire when revving it may be because it's too lean.
T.C.