Need new #1 carb body

It seems that the previous owner of my 1982 XJ550 Seca cross-threaded the pilot jet in the #1 carb (the carb on the left most side). I was able to remove the old jet and replaced it because I was rejetting for 4 to 1 exhaust and K&N pods.

The bike starts and runs great. However, the #1 cylinder is running very rich. #2-4 all run spot on, not rich, not lean, the plugs have a nice toasty-tannish look to them. The #1 plug is all black soot.

I am working under the assumption that due to the previous cross-threading of the pilot jet, it is running so rich because gas is not only flowing through the jet as it should, but also extra gas is leaking through the damaged threads. Does that sound right to anyone???

So, I was wondering if anyone out there might have a rack of carbs with a good condition #1 body that they would be willing to part out???

Less ideally, I have considered trying to put a smaller pilot jet in just the #1 carb to see if that might balance things out and get that cylinder running less rich. I’m not too thrilled by this idea though. Is there anyone that might be able to give me some advice as to whether or not this potenial remedy is viable. Or would I be potentially causing more of a problem?

 

I think your problem lies with the mixture screw setting 2.5 turns out is good starting point ...Where is your set at? I doubt the pilot jet would cause this.

 

I have checked the mixture screws. They were all set at 2.75. I did experiment with the #1 screw and set it at 2, which did make it a little less rich I think. But it is still way rich. So with that mixture screw closed much more than the others, for it to still be rich leads me to believe the problem lies elsewhere.

Just a thought...I never pulled the mix screw and examined it. If the mix screw itself was damaged, I’m guessing that could be contributing to this problem. That is something I will check this weekend.

 

There are small O rings on the mixture screws possible you have a bad O ring . Have you carbs been to church of clean? If so did you break the rack and replace butterfly seals?

 

I’ll check the o-ring. I’m not sure what you mean by church if clean. The carbs have been given a fairly thorough cleaning, but I have not broken the rack or replaced the butterfly seals.

 

Just thinking...wouldn’t the o-ring on the mix screw be sealing out air? If my problem was a too lean condition that would make sense, but I’m too rich.

Unless I’m wrong about the o-ring’s purpose being to seal out air.

 

Just thinking...wouldn’t the o-ring on the mix screw be sealing out air? If my problem was a too lean condition that would make sense, but I’m too rich.

Unless I’m wrong about the o-ring’s purpose being to seal out air.

 

Did you pull the needle out of the slide when you tore the carbs down? Had same issue with an xj550 on cylinder 4, all plugs perfect except #4 which was coal black. ......I had put the spring under the collar on the needle instead of on top of it.....lol, guess that was kinda important...

 

What the "church of clean" refers to is FULL tear down of carbs ALL rubber O rings and seals removed , all gaskets /jets /diaphragms removed , carbs removed from rack . In essence the carb body is stripped bare, then and only then will you submerge carb body in carb cleaner ( I use Berrymans 1 gallon cleaner from Autozone) for up to 1 hour per carb . Wash the bodies in hot water with a little dawn dish soap ,let dry and reassemble , this is the ONLY way to clean carbs ....Spray cleaner will not get into the small passages . When you do this method you need all new seals xj4ever is best source he has all the seals . This sounds hard but a day is all that is required and carbs come out looking great if done correctly . 2 seasons on my carbs now

 

I may have an extra #1 carb body . and you are talking about far left as you sit on bike correct

 

If the PO cross threaded the pilot jet, then yes. There is a high probability that is what is causing your rich condition. However, it's probably not simply leaking past the threads. You see, the threads are not what is supposed to seal one side of the jet from the other.

The pilot jet has a tapered nose on it that is supposed to bottom out and seal against the carb body and if he cross threaded it, it's likely that it isn't threading all the way in and is binding to a stop before that tapered seat bottoms out.

Here's a pic I took a number of years ago of a carb that I dissected. You can see the pilot jet and it's tapered nose. If that nose isn't tight against the carb body, fuel will leak around the jet in addition to through it:


So if that's what he did, then you're probably in the market for a new carb body. But you already knew that!

 

Rice_Burnarr thanks for the work you did on the carb photos I learned a lot from the photos for a better understanding of the carbs and how they work

 

Rice_Burnarr did a MAGNIFICENT job on the carb dissection project and it is one of the most useful (and most viewed) threads:

http://www.xj4ever.com/inside your carbs.pdf

 

make nice pin ups aside of my Vargas Girls . if i could be painted on my tank I would

 

My pleasure guys. Glad to help.

 

Thanks a lot Rice-Burnarr, those pictures are a huge help. Now that I can see exactly what is supposed to be going on in the, I think my problem is that the pilot jet is cross threaded and therefore not making a proper seal and is letting excess gas though. Looks like a replacement carb body will be my best option.

 

XJ550H, yes I am talking about the carb body that is furthest left when sitting on the bike. Any chance you still have it and how much would you be willing to sell it for?