Carbs Rich or lean?

[tweeleft]

Ok I have a Carb question.
First a 79 SF
Mac 4 to 1 exhaust
142.5 mains
45 pilots
Drilled stock air box
Uni filter
Slide needles in stock notch
I might be answering my own question, do I read the plugs to see if she is too rich or too lean. Another thing is the two inner pilot jets holes don't match the outer two. I can't remember the configuration. She purrs at idle, carbs synced, color tuned mix screws,carbs cleaned,no octopus. Seems to hesitate a little when cranked to Wot. Any help would be cool. Getting about 30 to 37 miles to the gallon on non crap fuel.


Thx Jerry

[petejw]

yep reading ur plugs is ur best bet,
tho they will only give u a general idea
of whats going on unless u do a plug chop.

ur 2 sizes up on the main jet and depending
on the size of ur air jet(back of carb bell) the 45
could be stock or could be 1 size up from stock,
from memory the 180/185 air jet had 42.5 pilot jet stock,
i think it was an air jet of 210 that had the larger pilot jet (45)

also check ur float heights are set at stock 25.7mm.

if u are running rich id put all the jetting back to stock
and go from there.

[Yard Dogg]

I'm not sure about your 79, but on both my 80 and 82, the manual calls for a fuel level check instead of just measuring your floats. He's right on chop testing. Throw a new set of plugs in, wind the bike out full throttle in top gear, then kill while pulling your clutch. You want to stop your engine at full speed without using it to slow down. Then check the color of your plugs. This is the best way to check whats really happening with your main jets, watch for police.

[natemoen]

I'm not sure about your 79, but on both my 80 and 82, the manual calls for a fuel level check instead of just measuring your floats. He's right on chop testing. Throw a new set of plugs in, wind the bike out full throttle in top gear, then kill while pulling your clutch. You want to stop your engine at full speed without using it to slow down. Then check the color of your plugs. This is the best way to check whats really happening with your main jets, watch for police.

there Is no spec given for the early carbs for a fuel height.

[tweeleft]

THX Guys, Forgot another issue she doesn't rev up when she's cold running on the choke(half, sputters bad on full choke). Could this be the diaphams?

[petejw]

theres a little jet that can get blocked
in the float bowls, check those out.

[Yard Dogg]

Yup, time to clean your carbs and go threw them, then chop test. Make sure you look at an exploded view because I'm currently going threw a 4 pack for an XJ, I've done this before, and I'm still finding passages I didn't know about.

One thing you may check if you take your carbs off is the intake boots. Make sure they are not cracked all the way through, and you should probably take them off and rework their seal on the head. It could be sucking air threw them. I doubt it if it's still idling smooth and tuning okay, but it's worth a shot.