Neophyte motorcyclist with an engine problem

[Lucien Harpress]

When I was checking the vacuum on one petcock, I accidentally sucked on the line connected to the fuel connection instead of the vac line connection. Unfortunately, I don't remember what I had it set on.

I'll check the hoses, but don't remember seeing anything majorly wrong with it. There might be something up with the right petcock, because there was a point when I only had two cylinders firing. The ones NOT firing were connected to the petcock that might have a problem.

If/when I do take the petcock apart, how should I do this and what should I look for?

[CatatonicBug]

If it's all connected correctly, it doesn't matter whether one petcock is not flowing. As long as one of them IS, then all the hoses are linked, and fuel should flow across all the carbs. I assume you are aware of the need for a vacuum from the engine to allow the fuel to flow, as long as the petcocks are NOT on the Prime position. Something tells me that you may not have torn into the carbs far enough. Did you remove ALL the jets? The main needle jet and it's seat should be taken out and the screen (filter) needs to be cleaned. The Pilot jets need to be taken out, as do the mixture screws. The slide needle (in the center, connected to the diaphragm) should be removed and cleaned as well.

The carbs are the single most problematic thing on these bikes, and you absolutely MUST take your time and be VERY detailed in cleaning them. If you miss ANYTHING in there, you will notice it once they are put back together, and you'll have to do it all again. That's why professionals can charge up to $200+ PER CARB to clean them!! It's not difficult, but you have to be detailed.

[trbig]

As I stated before, there's more you can do to the carbs, but what you've done will probably help it immensely. To the people that say you HAVE to take everything apart.. Bah! I have had the carbs off tons of times, but probably been into the float/needle jet and screen very few times and only do so if the needle jet leaks. Every time you remove one of these jets, it messes it up just a little more.

As for the mixture screw that you HAVE to remove... mine has been capped off and at the original factory setting for 27+ years and it idles and runs just fine.

"If it ain't broke, don't fix it!" is a great motto here.


Tod

[DGXSER]

Sorry Bug, but the way I have read it (Never owned a standard myself) on the Standard, there is no link from one petcock to another ie.. no OCTY, He will need BOTH petcocks open to get fuel to all four carbs unless he has changed his fuel line routings. ONE petcock only feeds TWO carbs in stock configuration.

[Lucien Harpress]

I didn't notice any connection between the two petcocks (and I was looking for one, because it mentioned it in the FAQ I used the take the carbs out). A messed up petcock may be my problem (I hope), or just one more thing to fix.

I think I'm going to monkey with it a bit tomorrow. I'm not in any rush to ride it, as I don't get my license until the beginning of July anyway.

[CatatonicBug]

Sorry Bug, but the way I have read it (Never owned a standard myself) on the Standard, there is no link from one petcock to another ie.. no OCTY, He will need BOTH petcocks open to get fuel to all four carbs unless he has changed his fuel line routings. ONE petcock only feeds TWO carbs in stock configuration.

Sorry 'bout that. Limited knowledge of the differences between std and spcl. That seems like a rather strange way to set it up IMO.

[DGXSER]

FYI, if you run on prime position on a MNS or a Special that still has the Octy, you will also need both petcocks open to feed all of the carbs. Prime does not go through the Octy to the carbs and they are not connected.

[Lucien Harpress]

I think I should call this bike "The Gremlin". I haven't done anything since the last time I posted, but this afternoon I fired it up, let it warm up for a bit- and it seemed to run fine!

I put some of that carb cleaner you mix with the gasoline in the gas tank, but other than that, I'm not sure what I did! I'm going to hope for the time being the problem is fixed, but if something else pops up, I'll be sure to post something.

Thanks for the help, everybody!

[CatatonicBug]

I think I should call this bike "The Gremlin". I haven't done anything since the last time I posted, but this afternoon I fired it up, let it warm up for a bit- and it seemed to run fine!

Not entirely suprising. It's strange how some things just "fix" themselves sometimes. Keep an eye on it though, because you don't want to get yourself stuck out on the road somewhere when/if it decides to come back.

[cywelchjr]

Sorry Bug, but the way I have read it (Never owned a standard myself) on the Standard, there is no link from one petcock to another ie.. no OCTY, He will need BOTH petcocks open to get fuel to all four carbs unless he has changed his fuel line routings. ONE petcock only feeds TWO carbs in stock configuration.

That is indeed correct. The standard has the octy built into each petcock, and one can go bad and the other be good. Actuallly the XS11 has two of basically the same petcock that the 650 and 400 use, it just has two of them, and they are mirrors of each other if their correct, if not correct (if you have two right side or two left side petcocks) then one will work backwards. And my original tank was modified so that on it prime was off, on was always on and reserve was the only one that was vacuum controlled.