Carbs are leaking

Hello all!

So I broke the post that holds the floats on my 650 carb, here's a pic



So I tried swapping everything from the '81 650 Maxim carbs into my '82 Seca carbs, but they leak when I put gas in them. It's just carb #3 that starts overflowing, I think. I noticed the exterior of the carbs are different, here are some pics.

650



750




Thanks for looking!

 

what number carb is that? is it the same number carb from the doner rack? it is my understanding that 650 and 750 crab bodies are identical accept for the jets. where is the fuel leaking from?

CN

 

Looks like it is a different carb indicated by the throttle shaft. Make sure you are using the identical placed carb on both racks. Hope this helps.

 

It's carb #3. The fuel is coming from where the floats are hanging. I'm using all the internal parts from the 650 i.e. jets. I tried dried setting them to both 650 and 750 standards and they're still overflowing.

All the carbs are from the 750 in the current rack I'm using.

Thanks for the replies.

p.s. the last time I worked on these was in Summer. I cleaned them and they've been in a plastic bag since. Finally have time to work on them a bit.

 

Did you try replacing the float valve and seat from the 650 to the 750? If you have a carb stand you could connect an aux fuel tank and with the float bowl off of #3 you can manually move the floats up with your finger to see if it is actually shutting off the fuel flow. Then wet set the float and verify the others for peace of mind. At least this way you will know if #3 is overflowing before mounting them back on the bike. Also check your oil for gas. If you smell gas then you have to change the oil and filter BEFORE starting the engine. Hope this helps

 

Get rid of the carbs they're junk. Fuel inject the bike that's the only way to go. How much do you spend on those junky parts? They have 3D printers now. I am going to use a mega squirt system om it.

 

This from the man who would replace a motor rather than adjust his valves.

The carbs need proper service and adjustment. There's nothing inherently wrong with them.

 

Glad I wasted time answering your question(s), sir. You are clearly outnumbered concerning 'XJ-enthusiasm' so no more advice from me to you specifically. I forgot who I was dealing with.

Sorry to get off track OP.

 

I live on SSI and If I known these bike were such junk I would have never got into this, How many post have I heard about these worthless carbs? They are junk bigfitz JUNK JUNK JUNK JUNk. I am 45 and NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER seen a bike with so many problems with the way they're engineered. How many post have I heard from people that are 5th gears done EVERYTHING and still they don't run right. As I said before I live on SSI. I am not a millionare like you are fitz. I can't afford to keep putting money into these pieces of junk. The prices they charge for parts you would think they were something made by Paul Jr. The reason I want to swap motor is I know the bike in the garage runs. I had it running on starter fluid. Both engine are 5N8 so it makes no sense for the carbs not to fit.. For Christmas my brother got me gaskets to do a float needle and seat kit.

 

really? are you just a sympathy seeker looking for pity? Everyone here has a story, some bad, some good. Who do you think you are in coming on this site and flaming it. You are just showing how much of a loser jerk you are. People on this site are here because they enjoy the bikes and the people. If you don't, then you are more than welcome to leave, whick you should. Hopefully you will be banned. No one needs your idiotism.

just in case you needed this..
idiotism
1. the condition of an idiot, especially an extreme degree of mental deficiency, usually a mental age of less than three or four years; idiocy.
2. idiotic conduct or action, especially in a normal person. — idiotie, adj.

 

Atlandf...

First off it's not bigfitz's fault that your stupid. He's a great person that spends his time helping people something that you've probably never done...

I'm 30. Never touched a motorcycle before this one took me sometime but I got it. It's not everyone's fault that your a stupid 45 yr old.

If you had a life you won't waste your time on this site. Just cause your A STUPID PERSON doesn't mean that you need to waste everyone else's time on this site listening to a 45 yr CHILD CRY cause he can't figure out your carbs.

 

If you can't get a bike to run with basic carbs you'll never manage to get a fuel map built for a DYI fuel injection system. You have to have a running baseline to work off of, unless you plan on going insane.

 

Too late.

 

Bigfitz!!! How dare you have a job and pay your own way in life.

Why is it that the people who scream the loudest about not having money, can afford cell phones, laptops, cable, plasma TVs, etc.? I know far too many people like that.

 

Yeah, I was gonna say, for the record: I'm considerably older than our kerfuffled member; I'm a single parent with a 120-mile daily commute; and I still WORK for a living. One of the primary reasons I own my XJ is to ride it to work and save money on gas. Millionaire, indeed. I wish.

 

Was so excited to see so many replies, but I see a troll has entered my thread

 

just ignore his posts and everything will be fine.

CN

 

Indeed.

The guy's not a troll, per se; he's got a couple of XJs and didn't realize that they're not Ford V8's and this isn't for everyone. So now he's frustrated (join the club.) On top of that, he seems to feel as though he (by virtue of his not-so advanced age and therefore unquestioned qualification) is THE standard by which all things mechanical shall be judged (it's not just Hitachi and Yamaha, we've heard all about Honda and their crappy cars too.)

Anyway, carry on. We're trying to help.

 

So, I just wanted to update this thread in case anybody uses it as a reference. I ended up using the "clear cup " method. Where you use a measuring cup to check the fuel level in the carbs and are able to see what's going on inside the bowl. What looked like carb #2 overflowing was really #3 overflowing, making impossible to troubleshoot with my limited mechanic abilities. Anyhow, I got the bike to idle without dying now. The spark plugs are black (I guess from running rich?) I can't find my Hayne's manual.

**Question**
I tried synching my carbs with a Carbtune, but wasn't sure what screws to turn to change the readings. I tried turning the synch screws, but nothing was happening. My compression on all four range from 115-120 psi.

Also, one end of the YICS tool doesn't have a rubber stopper on it (the one Chacal sells), can this be screwing it up?

 

Bargomer,

When using the YICS tool, you leave one bolt (opposite end of the chamber) attached/threaded in still. The tool you're using doesn't have a opposite stopper for that reason.

When doing a colortune, you turn the AF idle screws, each carb has one, at the top - flat-head brass screws with small tips -- easily damaged btw!

I do not believe you use YICS tool for that, but someone correct me here.

For a running sync of the carbs (your carbtune perhaps?) you adjust the 3 screws linking the throttle shafts together -- the bars that hold the springs/butterfly valves, that move when you twist the throttle.

YICS tool is used for that. Try not to go far above idle for that. Also, the pressure on the gauges needs to be similar/identical, but from my research, not at a particular value. They just all have to be at the same spots.

Hope that helps!

 

You're rich in spirit, Fitz.

 

Myth: fitz is a motorcycle snob that walks around with his nose in the air because he is too good for the rest of us struggling slobs.

Truth: fitz is as helpful to the members of this forum as they come! Just don't let your frustration with your bike turn you into a ranting fool.

Bargomer - You're gonna need to change those plugs to get a decent synch. I know it sucks to keep replacing plugs when they foul but you will never get a good running synch with fouled plugs.

I would suggest turning your pilot mix screws in a full turn before you try synching again if your plugs are that badly fouled. Did you start at 2-1/2 to 3 turns out?

I'm not familiar with the "carbtune" device but if it is a standard vacuum guage you were going about it the right way. Something else is not quite right if your synch screws were not having any effect.

 

The YICS tool needs to be used for both running synch and for adjusting the pilot mixture.

 

Well......if you have one. If not, you can get it darn close without a yics tool.

Dave

 

Okay, got it. Not having the other side of the YICS closed is what was causing the readings to be weird. Err....gotta wait for the weekend to work on it again. Thanks for the advice everyone!