Running on FUll choke... but that's about it

[dabien310]

Hey guys,

I bought my 79 xs11 sf about a week ago and it didn't run at the time.

So spent all yesterday cleaning the carbs out. I think I got every nook and cranny possible. Put it back into my bike with the pod filters and pulled the choke out all the way.

The bike idles, but stumbles on occassion. If I attempt to give it ANY gas, it dies. If I try to put in the choke, it dies. I also felt the engine and cyl 3&4 do not seem to be getting very hot.

THe exhaust comes out white with a smell of sulpher almost. It doesn't smell like normal good ol exhaust fumes.

Since I'm a newb, I don't really know what to look for or where the problems arise. ANy ideas?

Jon

[skids]

Re: Running on FUll choke... but that's about it

I don't know if you used the carb dunk tank method, but if you did, it is highly adviisable that you finish the job by shooting carb spray through all of the passages, followed by forcing air through the passages to dry them out. Of course, carb synching would also be important, but this could be tough considering it isn't running well, so getting them (throttle plates) close with a wire as a feeler gage might come in handy.

I have had a little luck starting the engine cold, with a particular set of carbs, by allowing warm-up time, rolling the idle up very slowly, followed by lightly "goosing" it to free-up the slides (I guess that is the mechanism).

Originally posted by dabien310
Hey guys,

I bought my 79 xs11 sf about a week ago and it didn't run at the time.

So spent all yesterday cleaning the carbs out. I think I got every nook and cranny possible. Put it back into my bike with the pod filters and pulled the choke out all the way.

The bike idles, but stumbles on occassion. If I attempt to give it ANY gas, it dies. If I try to put in the choke, it dies. I also felt the engine and cyl 3&4 do not seem to be getting very hot.

THe exhaust comes out white with a smell of sulpher almost. It doesn't smell like normal good ol exhaust fumes.

Since I'm a newb, I don't really know what to look for or where the problems arise. ANy ideas?

Jon

[Renegade]

If the carbs are gummed up really bad, look for a shop that has an ultrasonic cleaner for carbs. I went through the remove/clean ordeal several times with my 81, and still had problems. Someone suggested a local go-fast shop that used ultrasonic cleaning. $80 and a day later, the bike ran like a new one. Well worth the money for that service.

[Dennyz]

If you are starting out with a set of carbs that have been disassembled and not sync'ed, I have a process that works for me.

Manual Carb Sync Process

If you are starting with individual filter on carbs that have not been tuned for them, you could run into an extreme lean condition. This might explain while you have to leave the choke on. Try turning all four of you idle mixture screws out 4 complete turns. Once you get the motor running, turn each one in 1/4 turn until the idle stops improving. Do the sync'ing first.

If your carbs are in work condition, but just out of adjustment, these suggestion should get it running well enough to get it fine tuned.

Let us know how it goes,

[dabien310]

I broke down the carbs and cleaned them... took me the whole day yest. However, I did not adjust the idel mixture screws. I will try that and let you guys know.

The exhuast smells nasty.. almost sulfer-like.

Jon

[dabien310]

Ok guys... I seated all the idle mixture screws to 1.5 turns out and the bike starts and after 5 seconds dies with the choke all the way out. Makes a whining type of noise when it dies down.

Still can't figure out what else to look for. Any other ideas?

[rover]

Are you using fresh gas? Old gas can make the exhaust smell funny, and run really bad. Just a thought

[TopCatGr58]

Hey there Jon,

Okay, first just take the pod filters off for now!! Some brands have a prominent lip that partially occludes the air intake ports on the mouth of the carbs, usually causes more trouble with higher rpm's than just idle, but best to eliminate all areas of trouble!

Next, this is a Special, right! Do you still have the Octopus, that horrible multihosed thing that attached to the #2 carb, and had hoses going everywhere?! That diaphragm can get messed up, and either allow too much flow, or not enough! You need to make sure that you have fuel in ALL of your carbs! Pull the lines that go to the #3-4 set and make sure you have fuel flowing! Could also be a problem with the petcock on that side! With these specific carbs/cylinders misbehaving, it's usually a fuel delivery problem, electrical are usually paired 1-4 and 2-3.

Once you get all 4 cylinders firing, then it should behave better, and then you can check your intakes for vacuum leaks! Make sure you put the vacuum advance hose on the #2 Carb nipple, NOT the Intake manifold nipple!

[dabien310]

Yeah, I went to the gas station got 1.5 gallons of gas and mixed it with the gas in the tank. The gas in the tank was from when I bought the bike to see if I could start it. So all gas in tank is less than 2 weeks old.

Originally posted by rover
Are you using fresh gas? Old gas can make the exhaust smell funny, and run really bad. Just a thought

[dabien310]

Sounds like a plan. I checked the hoses and one seemed to have a good amount of air. That may be the problem. Where can I get replacement hoses? May have to try and ungunk the octipus' body with some carb cleaner.

As far as the pods, if I take them off, and start my engine, will that be ok?

Jon

Originally posted by TopCatGr58
Hey there Jon,

Okay, first just take the pod filters off for now!! Some brands have a prominent lip that partially occludes the air intake ports on the mouth of the carbs, usually causes more trouble with higher rpm's than just idle, but best to eliminate all areas of trouble!

Next, this is a Special, right! Do you still have the Octopus, that horrible multihosed thing that attached to the #2 carb, and had hoses going everywhere?! That diaphragm can get messed up, and either allow too much flow, or not enough! You need to make sure that you have fuel in ALL of your carbs! Pull the lines that go to the #3-4 set and make sure you have fuel flowing! Could also be a problem with the petcock on that side! With these specific carbs/cylinders misbehaving, it's usually a fuel delivery problem, electrical are usually paired 1-4 and 2-3.

Once you get all 4 cylinders firing, then it should behave better, and then you can check your intakes for vacuum leaks! Make sure you put the vacuum advance hose on the #2 Carb nipple, NOT the Intake manifold nipple!

[prometheus578]

You mentioned in a later post that you didn't adjust the idle mixture screws. Did you take them out and clean them when doing the cleaning? A bike that won't run unless on choke, means that the idle circuit is messed up, and relies on the choke circuit for fuel. Cylinders #3 and #4 don't seem to be working well, and there's that smell. If you have dual pipes, I'd check the muffler on that side for the "ol' dead mouse" trick. Don't laugh, I've seen that one.

[dabien310]

I'm gonna check it tonight. Can someone clarify this....

The idle mixture screws I have on my 79 xs11 sf is a stand alone needle with a spring. It looks different from my '80 xs11's carbs. In the '80 carbs they the needles acutally go inside and there is a place for the screw covers... is this normal?

Also, I looked on the site and they showed pics of the needle with 2 little rubber pieces.... I can't seem to find the rubber pieces... would they be in the hole stuck to gunk? I'm wondering if it would be a major problem if those were missing.

I wanted to say, you guys all have given me great feedback on all my questions and I really appreciate it.

Jon

PS... my exhausts are 4-1s and the jet sizes are 137.5... is that recommended? I have those pod filters.

Originally posted by prometheus578
You mentioned in a later post that you didn't adjust the idle mixture screws. Did you take them out and clean them when doing the cleaning? A bike that won't run unless on choke, means that the idle circuit is messed up, and relies on the choke circuit for fuel. Cylinders #3 and #4 don't seem to be working well, and there's that smell. If you have dual pipes, I'd check the muffler on that side for the "ol' dead mouse" trick. Don't laugh, I've seen that one.

[randy]

The idle mixture needles that protrude outside (78 & 79) don't have the o-rings. The mixture needles that are capped and are completly inside (80 & up) do have the o-rings.

Randy

[randy]

Sorry for the double post.

The 'kickback' whine when it dies is probably the starter clutch spinning. That can happen when the engines kicks backward on stalling. The backward kick is a symptom of out-of-synch carbs. Synch 'em up.

randy

[dabien310]

So you're telling me it's ok to shoot carb cleaner into the holes where the idle screws come out of not having to worry that there will be any rubber thingys in there. Will do ASAP.

Thanks for all the helpful info... I will let you know how things go.

BTW, I see you live in NY. Where you live? I currently live in Bellerose Queens... it's off the Cross Island.

Jon

Originally posted by randy
The idle mixture needles that protrude outside (78 & 79) don't have the o-rings. The mixture needles that are capped and are completly inside (80 & up) do have the o-rings.

Randy