WE KNOW IT'S NOT IGNITION .. CHECKING CARBs

[79XS11F]

Originally posted by skids
25.4mm per inch. What is MM?

Sorry number lock must have been off or I didn't hit the key hard enough. Should read "3mm is 1/12 of an inch.
Rob

[79XS11F]

Originally posted by randy
Like Skids wrote, there are 25.4 millimeters to the inch.

1 millimeter is approx. equal to .03937 inches.

**** millimeters, if you set your floats to 1 inch you should be fine!

Yes I did set all the floats at 1 inch and did so very carefully. The issue is that when the carbs are turned over and the bowls filled with fuel there is different fuel levels in each bowl. so the plan is to ignore the 1 inch rule and go with what ever is needed to get actual fuel levels all the same. Time consuming but hopefully worth it.
Rob

[79XS11F]

Originally posted by TopCatGr58
Hey Rob,

A further review and remeasurement of my carb bowls shows that the shoulder of the bowl is ~0.25" below the sealing surface. The manual says that the fuel level should be ~3mm below that surface, so when you say that the levels are close to the sealing/mating surface, how close??

Adjust the floats about 1mm at a time, use the float height, not just how far to bend the tang....that's too hard!

BTW, when you had the pilot jets out, did you notice whether they had the vent holes in their sides? Secondly.....may be a dumb question, but does your's have the screw caps for the pilot jet towers, or rubber plugs? IF they had NO caps/plugs, that would also contribute to an overly rich condition allowing the pilot circuit to suck up fuel thru the top of the pilot tower instead of thru the main tower and their shared tunnel!
T.C.

TC .. when you say "fuel level should be ~3mm below that surface" do you mean below the shoulder surface or below the gasket surface?
Rob

[79XS11F]

Well this should be somewhat convenient. Or at least as convenient as it can be. 1/12 of an inch below the gasket surface of the bowl is the thickness of a razor blade below the lip of the carb body that the bowl fits into when the bowl is on the carb. I will therefore go with that bottom edge of that lip as the fuel level mark.
Rob

[randy]

The issue is that when the carbs are turned over and the bowls filled with fuel there is different fuel levels in each bowl.

Then you, my friend have a problem with your floats. Some may be leaking, not floating fully. You can compare them all together in a bucket of water. Or, shake 'em and listen for gas sloshing inside 'em.

[79XS11F]

Originally posted by randy


Then you, my friend have a problem with your floats. Some may be leaking, not floating fully. You can compare them all together in a bucket of water. Or, shake 'em and listen for gas sloshing inside 'em.

Hey Randy .. Yes it is odd that the out come would be different fuel levels but the floats are not leaking. I did check them. Could be different weights caused by corrosion and or deposits over time. .. I guess. They are however DRY. They appear to also all be the same shape and in the same position with one another when lines up and viewed from the side. I would venture to guess that the bowls of these carbs have never been off until now.
Rob

[underdog57]

time saver

In the carb repair section , I read where a guy put a few pieces
of wood together and made it so the carbs would be leval on the work bench...A gas can above it and your set ...
no more re/re
I bet two screws per bowl would hold be good enough for the "mock up"

Check it out , has photo's etc ...
I will do float level by fuel level too ...

Hope you get it !!

I'm going through a few setbacks now .

Bob

[79XS11F]

Thanks underdog .. I have read that thread and that is why I am checking it that way now. I am however using a vise with great car to hold the carbs level side to side and front to back and front to back.
Rob

[randy]

Rob, do you by any chance have BRASS floats?

Or, is it possible that some of your floats are binding on the sides of the bowls?

[79XS11F]

Originally posted by randy
Rob, do you by any chance have BRASS floats?

Yes they are brass.
Rob

[randy]

Yes they are brass.

Take off all four floats and check them all together in a bucket of water. I'll bet they don't all float the same!

[79XS11F]

Originally posted by randy


Take off all four floats and check them all together in a bucket of water. I'll bet they don't all float the same!

There's no doubt in my mind at this point that they are not floating the same even if setup as per the manual. I will make the adjustment based on actual fuel level and try to find upgrade or different floats for the bike for next year.
Rob

[mro]

different floats.....for different folks

Think MikesXS has the plastic ones.



randy says

I'll bet they don't all float the same!

brass ones more prone to problemas, corrosion/leaks............

man oh man, seems your set of carbs been running you good. One set of 79' carbs I've been through went along with just clean and adjust with micrometer. 80's carbs were even easier



mro

[79XS11F]

Re: different floats.....for different folks

Originally posted by mro
Think MikesXS has the plastic ones.



randy says


brass ones more prone to problemas, corrosion/leaks............

man oh man, seems your set of carbs been running you good. One set of 79' carbs I've been through went along with just clean and adjust with micrometer. 80's carbs were even easier



mro

I'm just trying to get them as exact as I can so they can be eliminated from the equation if the bike will still not run.
Here's what I got for fuel levels in the bowls

#1 - 1/8" low of the mark

#2 - 1/8" low of the mark

#3 - 1/16" low of the mark

#4 - 3/16" low of the mark

Their not really very close to one another is you consider that the specs are quoted in 100s on an inch. #1 and #4 are 1/16 of an inch different. and #3 and #4 are 1/8 inch different.

Wish me luck getting them all the same.

Rob

[79XS11F]

Hey that didn't hurt too bad at all. I now have the fuel level in all bowls the same .. exactly the same. I flipped the carbs over a few times and have confirmed that the float valves closed each time. I have them "bench" synced and the air box is in place. When I finish the smoke I have in my mouth I will install the carbs.

DOES EVERY ONE HAVE THEIR FINGERS CROSSED ....

Just a note. All fuel levels were the same when all the tangs on the floats were FLAT with the pin brackets. Likely the way they were when they were stamped out to be manufactured. Perhaps the carbs have been tinkered with in the past because 2 of the tangs had slight twists to them ... who knows.

Rob