79 carbs on an 80 , match float height to year of bike ?

[Crazcnuk]

Where those screws end up is immaterial, unless they want to be right closed or too far out to keep the setting. You just set them where they want to be.

It also doesn't matter if they are all the same, they are only for idle.

Do the chop test, and that will tell us what your mains are doing.

My bike was doing exactly the same thing, I ended up rebuilding the top end. Mine was also burning a lot of oil, though.

[TDodge7]

i figured i'd add an update so you guys don't forget about me .

my family hit a rough spot and we all pretty much lost our jobs at once so money has been very tight , and it almost got to the point where i would have to sell the xs to keep the power on . luckily i'm pretty good at scraping up cash in an emergency , and the job situation is finally fixed . it's still going to be a week or two before i have any money again , so this post is kinda early , but i wanted to let you guys know how the bike is doing . i did all the chop tests and it was still coming out stinking rich . i tried riding it with the air filter out and the air box bottom on and it was better . then i tried with the air box completely open and it was almost perfect . i contemplated pods for a bit , but not having the money ended that idea , so i drilled out the air box . now the bike rev's and rides perfect literally all the way to red line , as soon as the needle hits red line i have a slightly rich bobble and then it pulls thru it into the red zone . since i'm almost never up there rpm wise i may just leave it as is until i'm bored and have more money , i'd rather be a little rich than a little lean . i guess she just needed to breathe , to completely fix the problem i think i'll need to go leaner on the mains , but only one or two sizes , it's so close it's almost not worth pulling the carbs again .


oh yeah , since these are the 79 carbs with the plugged pilot jet towers and the pilot jet draws fuel thru the main jet then if i were to change the main jet would i also be lowering the ammount of fuel that gets to the pilot jet ? or would it not make a difference pilot circuit wise ?

[TDodge7]

well i finally found a new job so i finally have some money , which means i can finish the xs now .

like i said in my last post , the bike now runs perfectly until it hits red line , right as it crosses into red i get the rich condition again for a second but if you stay on it it will pull thru the flat spot . now i don't intend on riding in the red but it would be nice to say it was completely tuned . i'm going to order some new main jets but since i don't jet much i was wondering , since it only hits a problem spot after red line is it safe to say that one jet size leaner ought to do it ? or should i order more than one size ?

also does changing the main affect the pilot jet since it feeds from the main jet on these 79 carbs ? (ie. will i have to change pilots if i change the mains)

[TDodge7]

anyone ?

[bikerphil]

I would try a size leaner on the mains, or if possible, open the exhaust up a bit for better flow.

[XSokieSPECIAL]

I had the same problem when I changed to 79 carbs on mine. Craz helped me a lot. I lowered my floats 2 mm and it runs almost perfectly. Still a little rich coming off idle but otherwise good.

I had that bog, or seemingly to drop a cyl at high end for a while but it seemed to work itself out after I changed the plugs and rode it for a while.

I am thinking of lowering the floats just a little more though. What do you think Craz?

[Crazcnuk]

2mm seems to work for most people. For that off idle richness, try adjusting the idle screws a little leaner (1/4-1/2 turn).

This fine tuning is where the color tune comes in handy.

The part I haven't figured out is the lack of power at the top end. Many of us have difficulty hitting redline in 4th (in a reasonable amount of time) and 5th is almost useless, other than to lower rpms.

I am running 120 mains (up from 110) on mine, and the plugs still don't show any richness at all even though my only mod is a K&N air filter. I live at 3500ft altitude as well, which should make it even richer.

I get 42-50mpg (Imp) depending on the day and how I drive.

[TDodge7]

ok , well i'm going to go ahead and order those jets . i only have a few more things to fix . most importantly the exhaust for cyl #2 . the original collar at the end of the pipe where it butts to the gasket has been replaced by a previous owner with a new horrible one , and it's welds have broken free . i'm going to have to get creative with the welder for that fix , but it should stop that pesky exhaust rattle .