Gas on backside of carburetor. Why?

I've been working on my 85 Maxim Xj700x. Today I noticed some fuel coming from the carb to airbox joint. Obviously on the air intake side of the Carburetor. Why is this?

The carburetor air/fuel mixture screw is around 3 turns out.

I was changing the clamp that holds the joint to the carburetor when I saw this.

 

your float valve is either sticking ,or set too high on that carb. you need to remove the float bowl and reset the float height.
also check that fuel has not leaked through into the crankcase oil. remove the oil filler cap and sniff, if it smells of "gas" you need to change the oil.
stu

 

If I remember correctly, the book calls for 17.5(+/-1) mm. I opened them, and all were set to 22 mm. I set them to 18.5, and the engine wouldn't start. Sprayed starter fluid, and the engine cranked, then died. I set them to 20 mm, and it runs just fine. I have not had a chance to wet set them.

I am curious if too rich of a fuel mixture could cause it.

 

The things that causes your problem.
1. Float height set too high (20mm is too high)

2. Stuck float.

3. Worn or perished float needles.

4. Perished float needle seat o-ring/ washer.


Did you break the rack and refurbish the carbs properly? If not then you're just going to be futzing with them until you get frustrated.
IN THE CHURCH OF CLEAN

 

after you set the float height you have to do a wet test of the actual fuel level just setting the float height does little for you other than give you a bench mark for readjusting fuel level


Setting the fuel levels

 

Smell your oil!

 

Also, when bike is not running, is your petcock allowing gas through when set to run or reserve? Is so, rebuid it, Chacal has kits.

 

Initial float height setting is 17.5mm. Then you do your wet setting from there

 

Makes sense. I just haven't found the zircs to tap into the carb bowls to do the wet set. I will in the near future.

I do not smell gas in the oil.

It does leak when left on run. It does not leak when on Res. I did install an inline fuel shut off, and I leave the stock set to res. I've not yet forgotten to turn it off. ( Rebuild kit was ordered from eBay 3 days ago.)

I will get around to it one of these days. I don't ride it that much due to weather... But I do feel that doing the wet set will fix most of my problems.

 

Start a conversation with Chacal. He has what you need, in stock. You won't find them very many places, and no grease (zerk) fitting will do the job.

 

Okay, so I'm getting irritated with trying the wet set. I'm going to say screw it, and just set the floats back to 17.5 mm.. What part of the carb body do I set it to? The portion where the carb gasket sits? Or the outer lip of the carb?

 

The floats on these carbs are rounded. So I have no idea of where I should be measuring to and from. First time around, I measured from the gasket mating surface, to the side of the rounded edge... Where am I supposed to measure the 17.5mm to and from?

 

Where did you measure this ^^^ from?

Looking at those pics, you should do as KMoe suggested and get yourself to Church son.

 

In this picture, I measured from the flat surface that the gasket sits on, to the edge where the red line is.

 

Going by the 17.5 mm +/-1... I have to bend the tang backwards... This picture is taken with the tang bent flush with the rest of the float. I noticed after I did this, the carbs start flooding from the overflow.
I also noticed, with them set as close to 17.5 as I can get, the top of the floats press against the bottom side of the carb, not allowing the tang to depress the spring in the needle.

 

Float height is a cumbersome method to use in setting the FUEL LEVELS..............it's a "cheat" method that has a number of problems, starting with one you ran head-on into (where do I measure from?). If you want to use a float-height procedure, then what we recommend is that you get one carb's FUEL LEVEL set properly via the clear-tube method, and then measure the float "height" (in whatever easily-repeatable manner and measuring points that you choose)...............and then apply that float height procedure/measurement to the other three carbs, which will GET YOU CLOSE to being correct. And THEN, measure the fuel level (using the clear-tube method) in the other 3 carbs and adjust/tweak as needed.

Fuel levels are critical to proper carb performance, and setting them correctly is a pain in the bowl..........in fact, I'd argue that it is THE biggest hardship in the entire carb rebuilding process....everything else is purely mechanical in nature, fuel levels are "finesse" and "artistic". Luckily, once set properly, they should remain that way for many years (wear to the needle and/or seat is the only thing that will change them).

So take your time, have a punching bag of sorts handy to take your frustrations out on, and get it done.


http://www.xj4ever.com/setting fuel levels.pdf

 

The problem I'm having is that everything and everyone says the float is supposed to be 17.5 +/-1. I can't even set my float to 17.5 because I would be bending the tang past the "flush" point on the float. The picture shows the float level with the tang bent flush. Even at this, I can't get the fuel to show a consistent level with the clear-tube method.

I found another thread somewhere on the web, and that person had the same problem. Their's was set to 22.5 mm when they pulled the carbs apart. And they had problems with the 17.5 mm levels.

I'm just confused as hell. My understanding is that the tang should never have to be bent the opposite direction, but to achieve the 17.5 mm float height, it would be.

 

the tang is to be bent past the flush point of the tang bracket on float

 

That is how I was doing it. I actually saw that picture earlier. But I can't set the float at 17.5 mm because the tang would be bent the opposite direction in that case.

 

The last picture I posted is of the float height, with the tang bent even with the rest of the metal. The top of the float rubs the inside, bottom of the carb with the tang bent flush... I can't bend it any further. And it is still around 19 mm.

 

Make sure that your floats are not in upside-down!

 

also you do not press down on the float it is measured where it sits with carbs upside down.
floats should bounce when taped like a telegraph key

 

They aren't upside down, they look like the picture XJ550H posted.

I angled the carb to have them sit against the needle, but not press on the needle when I set them.

I'm about done with working on it. It'll be put up for sale soon.

 

Someone please correct me if I'm wrong, but I don't think it matters which way the tang is bent. As long as everything is installed correctly, you're only concern should be getting the fuel level within spec. I have done 3 wet settings so far, and they are absolutely the most obnoxious thing I have had to do with these motorcycles, but it does get better (having a proper set up makes a world of difference) The wearing of the seat washer, and needle tips (mostly if you have the rubber tips ones) can cause variation between each carb. Mine had fairly different settings the first time I did mine and kept the old needles, you could see the difference in the tang heights without measuring.

 

I suggest putting your measuring instrument down for a bit. Bend them all so that when you bottom out the needles (resting or bouncy like XJ550 says) there is still clearance between the float and the body, say 1 mm. You can't set the fuel level any higher or you risk touching the float to the body before the needle bottoms out. Put them all like that then do the wet set. Remember you can't take the level any higher than that, so in all likely hood you're going to be lowering the level, or you might just have it right with that. Make sense?

 

If you haven't gone to Church and replaced the worn float needles and seats you very well could be chasing your tail.
You mentioned that the floats are rubbing on the bottom of the inside of the carb . . . rubbing shouldn't be happening anywhere. Unless you are saying that they are resting on the bottom of the bowl??? Which would be a condition where you want your needle open to fill the bowl.

My carb rebuild must have been an anomaly; Hitachi's (squarer floats) dry set at 17.5mm (not very far off to start with) and all 4 bowls were within spec when checked wet. I should buy a lottery ticket!

 

Two other points:

If you're leaking fuel with the floats set too high, your needles might not be sealing.

What are you using for your fuel source? If it isn't flowing fuel freely, that can cause issues with the wet set (BTDT)

 

That won't get you where you want to be.
Brathe deep, go slow, and be paient. This is a new skill that you are learning, and it will take time.

In your pics I noticed the telltale stains of fuel residue around one of the throttle shaft seals. Fuel only gets there from one source; a leaky seal. Leve it as-is and you will have another round of frustration once the cabs go back on.

Go to church. Do it once. Do it right. It'll seem like a hassle now, but you won't have to touch the carbs for another 30 years.

 

If I bend it any more to try to get a 17.5 mm height, the float will be pressed against the bottom, inside of the carburetor.

I've tried multiple ways to get these carbs set, and I don't know what else to try with them as is.

One the top of these floats, there's a little divot, it is there to prevent them from hitting a rounded edge inside the base of the carburetor... with the floats set to 17.5 mm, I can flip the carburetors over, and press the float to check the needle spring... and when I press the float, I can hear/feel it rub, and if I look hard enough, I can see WHERE it rubs, just not actually SEE it rub.

I hooked up the clear tube. Tested them several times a piece, and a few times I got around 6 mm from the bottom of the carburetor. The majority of the time I got around 4.5 mm.

I have not changed any of the throttle shaft seals. I've put too much into this piece of crap and I'm ready to be done spending money on it. I understand what you're saying... I should buy them and replace them THEN work on this issue. Part of my issue is, I kinda regret buying this.

I said screw it, and I put it back together. Test drove it, and it runs like it did before. Lots of power, and Speed. I think it's just time to let someone else fight the fight.

I bought this bike for $600. Tags and Title were $340. Parts so far have been another $430.

It's not even worth what I've spent, and that's not even including the Tags and Title.

 

Billy, your math on purchase and parts is $1030.00. Tags and title aside (you'd have that on any bike), you're still not in bad shape. These are great bikes when you finally get it right. She's old... She was great once and could be great again.

If you can't see yourself putting in more time... It might be time to let her go. You'll probably get a majority of it back.

Your alternative is a new bike... And a payment.

 

Yea, let it go. If it ain't fun don't do it. If you feel you spent too much already, as Nuch just said you aren't really in a bad position. Be aware that you may need to spend even more on parts to make the bike safe and reliable.

But here is where the rubber hits the road . . . YOU have to be able to make the bike safe and reliable, cause there ain't no shop in town that can do it to the level of proficiency that is required. If you don't have the patience or the time to tinker with it, let it go. You tried, you did your best - no harm no foul.

 

In all reality, I bought it to use for trips to south Texas. I was told it was road-worthy when I bought it. Seller was full of it. I've had it around 3 months, and I'm still working on it. Had I known I'd have spent what I have so far, I would have thrown another $1k-1,500 and gotten something newer.

I just made a dumb decision and bought an old motorcycle. Riding it is fun, but having to keep checking the oil, for gas, is a pain.

I got the petcock rebuild kit in today... Put it in, and Viola! Still leaking... P..O..S...

 

I did forget to add a few things to this math. $235 was left out. I left out the rubber joints for carburetors to air-box, air filter, air filter oil kit, and then a few accessories. (Windshield $40, and Saddlebags $65. I shouldn't be counting these...)

 

You didn't read the Information Overload Hour did you?

News flash: the majority of previous owners will tell you what you want to hear just to sell their bike. Now is your chance, put it on Craigslist. Please refrain from saying the bike is a POS.

Fact: many members here have been faced with the same or similar issues while recommissioning these old XJ's. They have succeeded, the old XJ's are NOT P.O.S.'s.

 

I had the same thing happen (you'll start to hear that from others here as you post issues you come across). Petcock buffed to a shine, new kit installed and IT WAS STILL LEAKING! Arrrrgh!

Then I posted this issue to the forum. Guess what... I got my answer!

Sometimes you have to slightly "peen" (for lack of a better term) the metal disc (dish?) that sits against the rubber diaphragm. In other words, get an oversized socket, place the diaphgragm assembly at the open top (bolt side) so that it sits at the edge of the socket. Take a hammer and EVER SO GENTLY tap so that the dish "cups" and will sit better both against the rubber diaphragm and in the recess inside the petcock body. Again it is a finesse thing... you don't need much!

If fuel is getting somewhere, where it shouldn't (especially WHEN it shouldn't, you have to stop it at it's source first.

It seems to me that if you saw some small success, you'd change your mind about the old girl. There's something special about cursing down the road on two wheels knowing that you yourself made it possible.

 

Ahh...I think you meant cruising down the road, there's already enough cursing and he hasn't left the drive!
In all seriousness Billy, I think you're almost there. Also, there's an education process coming with your expenses that you're not considering.

 

The initial setting of 17.5 mm is only applicable if the float valve assembly is OEM. If either the valve assembly or needle is longer or shorter, then a different float height setting will be required.

Inconsistent reading indicate either a sticking needle valve or a problem with how the testing is done. The first fill of the float bowl is not always accurate, and it should be done several times to ensure consistency.

Sticking needles can be caused by old worn / damaged parts, poor manufacturing of parts, or incorrect geometry that was a result of installing a float valve assembly that did not place the needle at the original location.

Wet setting is a two fold process. First it ensures the correct height of the fuel for best performance. Second, it will verify the integrity of the parts and ensure no overflowing of the carburetors is occurring. Once consistent numbers are observed, it is prudent to let the carbs sit for at least an hour or so to be sure the fuel height is maintained and no leaking past the valves is occurring. Several iterations of this is a good idea to be on the safe side.

 

Are you referring to the disc on the actual diaphram? Pictures?

I understand... but this education process has drug on for far too long. I'm ready to be on the road, with no worries of whether it'll break down. If I head to 4 hours south, and I break down. I'm on my own.

I'm pretty sure everything is OEM, idk if it's original though. I know the guy who owned it before me only had it 4 months before selling it, he didn't do much to it.

 

Here is a recent link that covers the Petcock issue: http://www.xjbikes.com/forums/threads/xj700-petcock-problems.110963/

Billy - if you are REALLY in this and want it to happen I suggest the following.
Put your wrenches away; read like a thirsty man drinks water. Information Overload Hour is first. Then read the Church of Clean because your carbs should go there (floats can hang up if the hinge pin is varnished/gummy; float needles/ seats will leak if they are 30 years old).
Now grab your tools, clean/ refurbish your carbs proper. Rebuild your petcock. Put it together and reassess your situation.

All the while you are reading and doing the above. Hang out here and READ - that's right - read some more. Go through other peoples topics, things will start to stick. Things like, how to approach certain aspects of a motorcycle without buggering other things up; discover that you are not alone with your leaking petcock/ won't start/ flooding carbs/ high rpm's when hot/ etc./ etc. issues. You also will learn that the people that reply to cries of help generally know what they are saying - so listen and DO as they suggest.

Now grab the book Zen and the Art of Motorcycle Maintenance and you guessed it - READ IT - cause you need it grasshopper. Getting angry/ frustrated and cursing the bike is wrong and 10 times out of 10 leads to failure.

 

Ok, Here it goes...

Please keep in mind that these two pictures of rebuild kits are NOT for your petcock (per se)... honestly they came from a quick image search, but they illustrate BOTH sides of the diaphragm component of the rebuild kit. Pic 1 has the nipple/o-ring side showing and pic 2 shows the dish side.

You would be "peening" from the dish side (into the socket as stated above) to make the nipple/dish go just slightly further into the recess to make a better seal when at rest (or not under vacuum pressure from the intake manifold).

Also consider replacing the spring (standard kits do not come with it). as yours currently may have lost it's "springy-ness!" You could put a tiny washer at the base of the spring as well to add tension. Not too much tension mind you... you don't want the vacuum created by your intake manifold to have to work too hard to actuate the diaphragm.

I emphasize again, this takes patience. I've come to realize that putting these things back to functioning order is a bit of an art form.

My petcock STILL LEAKED after pulling the damn thing apart 3 times... I was about to give up as well and pull the trigger on purchasing a brand new one... but then I waited... The tank was off the bike on the workbench. I realized after the 3rd time I opened up the petcock and put it back together that the leak was there, but getting slower. I put a cup under the petcock and after about 2 days, it had stopped altogether.

The point is that it needed to SEAT itself. Now all is right with the world... or at least all is right with gas flow from the tank.

I approached my XJ a bit differently from you. I spent a hundred bucks more than you on my initial purchase and it was not running at all. The first thing it did was piss a huge puddle of fuel all over the garage floor. With no prior knowledge of working on motorcycles, I was beside myself. The only thing I knew was that waaaay before I could swing my leg over it and zip down the road, I had to stop the gas from leaving the tank on it's own. Since then, I've rebuilt the carbs and have done many, many other things and this was only possible with the guidance from the people here.

One last note...

If I do break down at some point... With all of the experiences I've had so far, a fix to the given problem could be potentially and logically "walked back" from something that WAS in working order.

You're gaining knowledge, a sense of accomplishment and ultimately control over your wallet as you'll have to rely less on "professional" shops to diagnose and fix your issues.

 

This is so true, once you get everything back in running order, you can more easily diagnose issues. In the meantime, getting the bike to run right is a 'cumulative' thing as you address neglected maintenance.

And my bike was never a barn queen, so its "issues" weren't extreme, but after finding this site, 4 years later it is running almost as good as the day I bought it new in 1985. I have put about $1k in parts in that time...but...

...once you make the initial investment, you will have a bullet proof bike that is almost as good as anything for 5x the investment (granted you won't be able to sell it for that much, but you will enjoy it that much)!

 

Here, Here!

 

Every machine breaks down eventually. In all honesty you won't find a used motorcycle that doesn't need work, not even if you spend $10K on one (well maybe then, if you buy right). The advantage to buying what you did, and what you're going through now, is that when it does break down you won't be waiting for a tow truck because you will know how to fix the problem and carry on.

Having said that; I did a full recomissioning four years ago, over the course of several months, and have not yet had a problem that ruined a trip. Your XJ will be safe and reliable, but it will only happen on the bike's timeline. 30 years of not being properly cared for has to be addressed first. Once you're done you'll have less into it than it would cost to buy and ready any newer motorcycle. My son's motorcycle is 20 years newer than mine, and needed a few hundred in parts to be safe and reliable. He spent $3300.00 in total. I spent $1900.00. Both of us have the same amout of fun, but I can afford better dinners