Hard starting and running woes

[TopCatGr58]

Hey RB,

A tube connecting carbs 2-3 is NOT a feature on the XS11 carbs!!

This would bypass the float valve/needle seat setup, and would not allow proper control of fuel levels!!

Here are a few photos done a few years ago with an older Dig Cam, so they are not as sharp as could be!! They are from a 79SF, but it sounds like from your descriptions you either have a set of the bastardized transitional 80 carbs, since you have the 4 inlet bell holes, the pilot SCREWS down in a tunnel, 115 mains, it's just the possible 2 sets of inlet "T"s that is confusing??

IF they are truly XS11 carbs, then I would PLUG up those tunnels between 2-3 carbs, and connect the fuel lines to the LOWER "T" between 1-2 and 3-4 carbs. IF they have the 4 inlet bell ports, then the float bowl should vent thru one of them. I think the flooding you were getting was because the fuel inlet between 2-3 was NOT going thru the FLoat valve needle seat and THAT's why they were flooding when you capped of the alleged VENT "T"!?




Here's what the insides "MIGHT" have looked like when you first opened them up!


And here's what it should look like once you've done a proper cleaning!!


Of course there's always the chance that the PO got a totally different set of carbs and put them on there, but I doubt it!
T.C.

[rbmgf7]

ok, here's a pic



so, i need to replace the two aluminum straights with the tee's and plug the current tee between 2-3? then feed fuel to the two new tee's that replaced the straights? so i was right with the two current black tee's between 1-2 and 3-4? those are still breathers?

[rbmgf7]

ok, so i did what was pic'd from the other carbs. now i don't have a plug for between the 2-3 carbs. i just used one of the stright pieces. will this be fine or will it cause some sort of imbalance between carbs?

[mro]

Hi rbmgf7,
carbs in pic look like there the after market bs34's sold to KZ riders in the early 80's.


mro

[prometheus578]

"Holy B'Jesus... he's found the missing link!"

What a hermaphrodite!
Never seen one, (thankfully) but hear that they exist.
(Ok, I've been on questionable internet sites and have seen them... along with naked midgets and such, but...)
Could this be a transitional carb set up?
Could this be a set up from another bike that uses these carbs?
Could the previous owner have decided that he knew a better way to do things?

Now, I'm not gonna say that these aren't stock.. (for some thing), but they look a little odd.

It has four holes...(One supposedly for the bowl venting), but also has "T"s for bowl venting.
Now, I seem to recall that you stated that some of the holes don't work. In the pics, the lower left hole would be for venting.(If the carbs were upright, that wold be the upper right)
If that passage is factory plugged, then the venting would come from those upper "T"s.(with the carbs upright)
I believe you also mentioned that when you plug the "T"s, the carb's flooded. This makes sense now. I can imagine that those holes are plugged and the "T"s provide the venting.
Thats' OK.
Now then... normally, there's two lower "T"s, between carbs 1 and 2, and also between 3 and 4 to supply fuel.
This setup has one "Master T".
Now...
I'd never buy a CD recorded by "MC Master "T", as I can't stand that style of noise(Note how I didn't say music)
What's happened to music these days? Who's in charge, there?
I mean... What kind of culture do we have?
Abysmal, it is.
Where's the Pink Floyd? Where's the old "stones"?
Oh sure.. they're in my CD rack, next to my Patsy Cline and Hank Williams(Sr, not Jr.)
Britney Spears... Justin Timberlake... Just who are these people?
Sure, I recognize the names from sitting in the bathroom at my mother's place, reading the "Enquirer", but..., usually, I'm just doing the "Star" crossword puzzle.
Muttie... she makes a good meatloaf. Oh sure, we don't always get along, but she's my mother and I have to be nice...

Oh...!
Tough...
When my train of thought jumps the track... I take everyone along for the ride.
Back to MC Master "T"...
Anyway...
That master "T" should be OK. Bikes with only one petcock run perfectly well with a master "T".
I'd never run with anyone called Master "T".
I'd never hang with Mr. "T", either.
That whole "A" Team show was a joke. I don't know why they ever allowed crap like that on TV in the first place!
Sure, it was the '80's, but is that really an excuse?
If ya want my opinion, I'd say tha...............................

[TopCatGr58]

Hey RB,

Well, "we" hope we haven't put you thru a lot of unnecessary work?? As MRO said, If those are aftermarket carbs, they "MAY" be plumbed a bit differently than the XS11's?

You need to determine IF the lower "T" connection and tunnel goes to the Float Needle Valve Seat, or just into the carb body float bowl vent area??

The info we were providing was for OEM carbs, but if they are truly aftermarket, then it depends. The upper "T" fittings do look like bowl vent tubes, and you should be able to determine that by spraying cleaner into the "T" fitting and see it blow out the Float bowl side to confirm that. Do the same thing for the "T" fitting between 2-3 carbs. IF it DOES go to the tunnel that leads to the Float needle seat chamber, and also can continued to the OTHER carbs...then it looks like THOSE carbs were setup to supply fuel thru 1 fuel tap, that would then flow across the metal pipes to the other carbs. ??

The OEM XS carbs....there are recesses molded into the sides of the carb bodies, like the OUTSIDE of your 1-4 carbs, but they are not drilled THRU...are closed.

Sorry, but you'll need to investigate the fuel supply connections a bit further to determine this, but still, yes, you can still plug the openings between 2-3 and put fuel "T" fittings between 1-2 and 3-4 and they should plumb and work like the OEM.
T.C.

[rbmgf7]

it's ok topcat, my carb install/removal times are getting faster, lol.

yes, the one Tee between 2-3 did supply fuel to all the carbs but i went ahead and replaced it with a straight and replaced the old strights with Tee's. now i fuel the carbs between 1-2 and 3-4.

the upper two tee's are vent's i squirt carb cleaner and they drip out of the bowl.

this new setup made no difference. started the bike and it still shows similar sympotms. it'll start good with the choke on (idles around 2.5k) and once it's warm, it'll idle without the choke (right on 1k). once i go to throttle, it tries to rev (maybe up to 2k) and die. it's being starved somehow but i don't know what from. i'm not even past 1/8th throttle. it would have to be on the idle/slow jet circuit right? lemme try and remove the rubber plugs on the slow jets again and see what happens.

it still "pop's" throught the exhaust like a lean running engine.

[prometheus578]

the carb has 115 mains and the slow jets are unplugged

Ok... you should not have plugs over the pilot jet towers.
Two different carbs styles.....
One style has the plugged pilot jet tower. If you remove the plug, you can see a small hole that connects to the main jet tower.
With this system, the main jet, usually a large number like 137.5 draws in fuel. Part of that fuel is then directed, through that channel to the pilot jet (The tower being plugged)
The other style... The tower is not plugged, hence, the main jet can be smaller(#110, #115, etc) as the unplugged Pilot jet can get it's own fuel.
Now then... you have 115 main jets, if I 'member correctly. In that case, I can imagine there is no "cross-over" channel in the main tower to the pilot tower, and that the pilot channel must then remain unplugged to get it's own fuel.

[rbmgf7]

Originally posted by prometheus578

Ok... you should not have plugs over the pilot jet towers.
Two different carbs styles.....
One style has the plugged pilot jet tower. If you remove the plug, you can see a small hole that connects to the main jet tower.
With this system, the main jet, usually a large number like 137.5 draws in fuel. Part of that fuel is then directed, through that channel to the pilot jet (The tower being plugged)
The other style... The tower is not plugged, hence, the main jet can be smaller(#110, #115, etc) as the unplugged Pilot jet can get it's own fuel.
Now then... you have 115 main jets, if I 'member correctly. In that case, I can imagine there is no "cross-over" channel in the main tower to the pilot tower, and that the pilot channel must then remain unplugged to get it's own fuel.

now here's is where you're gonna hate me. there is a crossover hole between the main and slow. i just ran a small wire throught the main and it popped out in the slow. i think now i might need bigger mains since the slows are getting starved from the 115 main. seem like this is what's causing the bike to die after a little throttle?

[prometheus578]

"Ok, these carbs came from an "Alternate Universe."

I've seen stuff like this happen on "Star Trek", so I know it's possable.
Suggestion:
Run #137.5 Main jets.... and plug off the pilot circuit tower.
Part of the juice from the main jet tower then will flow into the pilot jet tower and fuel that, too.
See, everybody then will be happy.

We can only hope that the pilot jets are still around#42.5 or so.

[rbmgf7]

yup, i think this is the ticket. i had some spare mains so i drilled them out to 140ish. the bike is able to idle and run through the revs without dying.

[TopCatGr58]

Hey RB,

What you've described is very similar to the ODD 80 carbs that Yamaha put out during the transition. One thing you'll want to look at is the Main Jet NOZZLE/Emulsion tube. For fuel to be able to be shared between the main and pilot jets THRU that tunnel, there needs to be a matching hole in the end/side of the Nozzle so fuel can get from the main to the pilot.

As long as you've got that opening in the nozzle, then doing like Prom said, putting a plug over the pilot jet tower, and going up to the stock 137.5 jet size "SHOULD" get it to be able to run when you turn the throttle.



I believe it was Crazcnuk that had a similar set of carbs, but I think his DIDN'T have the hole in the Nozzle, so even though he had the sharing tunnel, his main jet nozzle didn't SHARE with the pilot jet tower, SO...IIRC, he used the smaller jets, no caps on the pilot tower, and it worked like the later 80-81 carbs!?
T.C.