Carbureator Problems

I am rebuilding the carbs on my 1980 XJ650G. I have run into the following problems I hope someone can help me with. When first starting the bike gas will start to run out of the intake filter drain. I have purchased a petcock rebuild kit and have purchased 4 rebuild kits. The carb kits have a small silver round piece of metal included and I do not know what they are for. I am waiting for the petcock rebuild kit to come in the mail. Can anyone give me some help

 

Are they the washers for the float needle seats?

 

The pieces I see are like a small round metal plug. With the floats properly adjusted are the float needles supossed to be completely shut to stop the flow of gas? The small tab which secures the needles does not contact the needle and allow the needles to close.

 

Yes. Your floats are not seating properly or adjusting the flow properly to prevent overflowing the carb(s). It isn't a petcock issue, its a carb float issue. You're going to have to pull the carbs again and see what is wrong with them and why they aren't seating. The last set that I rebuilt, I had to pull them off and clean out the needle/seat better as they were still a bit too gummy.

 

I think they ar eblind plugs. I don't know off hand what they are for. As far as your other ? I would have to see. I'm not a skilled motorcycle mechanic.

 

The plugs that you see are for the air/mixture screw cover. I never bothered to put mine on. Its just a plug to keep people from messing with it

 

I want to thank you for the help. I now have a direction to go in to solving the problem. One more question. Is there a way or measurement to use to set the floats with the bowls off?

 

With the carbs inverted the bottom of the floats should be 17mm from the lip on the carb body (where the float bowl mates). You need to make sure that the floats are not depressing the little plunger in the center of the float needle to set accurately, so you may have to incline the carbs a bit.

Then, after you put the bowls on carbs but before you reinstall the rack on the bike scribe or pencil 2 lines on the number 1 and 4 float bowls in line with the center of the slide. One line will be 2mm below the carb lip and the other 4 mm below the carb lip. With the motorcycle on the center stand you can check that your levels fall between the lines.

NOTE: When checking the fuel levels you need to have NO air bubble in the clear hose. It will cause you to falsely read a low level.

 

if you go to my profile and look at the thread about me needing help on the first page on the bottom is another way to help set your floats. They have to look like the one in the pic at the bottom of the page. That should get you close. Then on the second page is another pic that shows you how to check them once the bowls are on and you have them on the bike.

 

The Plugs are for sealing the Pilot Mixture Screw Holes after you get done tuning. You can throw them away.

I'd rather fill the hole with a tiny bit of Bathtub caulk, anyway.

Save yourself some time.

Take the Carbs off and use windshield washer fluid to set the float heights.
Find one close or right on ... one in four has to get you close ... right?

Adjust that one until you are as happy as can be with it.

Then, flip 'em and MEASURE the Tang Height with a narrow machinist ruler.
Get the Value of the TANG HEIGHT CLOSED ...
Now, just do the other three to the same Value.

I use a "Holley" Float Height scale that you ought to be able to pick-up at a Speed Shop.
I trimmed the Plastic Ruler to Fit Hitachi and Mikuni

You only need to find ONE Float Height that is right.
Drain the Carbs
Measure the inverted Height of the TANG on the good one.

Bent the other three to match.
No Muss, No Fuss and you only do them ONCE!

 

Again, thanks for all of the help.

 

when you put her together, did you look at a parts diagram? when I did mine afthe being apart for months I could not tell the right direction of the floats.so I down loaded a parts diagram and I almost put them in upside down. I did put the pilot and main air jets in the wrong place.