How to run 85 XJ700-N Maxim without gas tank and petcock?

Howdy Folks,

Just got a 1985 XJ700N Maxim that was sitting for about 3 years. Previous owner said the bike ran before stored. We heard this story a hundred thousand times before...

Apologies in advance, I am a complete and total noob when it comes to fixing motorcycles.
I've started reading the xjbikes forums and want to say, what a great community of enthusiasts helping each other out. Great to see that these forums still exist.

After bringing her home started making a list of what it will need to get her running:
1. Removed battery. Checked levels, add distilled water and charge with a battery charger overnight.
Next morning, turned on the bike, all lights working.

2. Rusty tank. It has been removed and will be either vinegar soaked or electrolysis, still debating which way to go. Petcock seems to be in good shape, removed from the tank and found the plastic filter separates from the petcock but can be stuck back in. Is this normal?

3. Removed spark plugs, sprayed a bit of fogging oil into the cylinders, cleaned up the spark plugs and put them back in.

4. Ran the bike for a bit with starter fluid sprayed through the air filter. She started right up. It was nice to hear her voice.

5. I purchased one of those gas feeder holders on Amazon, thinking I could pug it in to the fuel hose (clear tubing that was connected to the tank and plugs in to the top of the engine. I had it all setup, opened the valve on the gas feeder and tried to start the bike. I could see the gas being sucked into the engine quite fast but then all of a sudden I realized it was coming out of the carbs and leaking all over my driveway. didn't think to put a container under bike, so had about .5 liters of gas running down the driveway...
She did run for a bit, and was able to confirm all 4 header exhaust pipes were getting hot. White smoke was coming out of the exhaust. Can someone please confirm if gas mixed with fuel produces white smoke?

6. The metal rings connecting the rubber boots between the carbs and the air box were loose so I tightened up but gasoline was coming out through these tubes specially on the second carb.

Therefore, Is it possible to run the bike without the actual gas tank and petcock in place?
Wanted to warm up the old oil in there before I change it.

The long term plan is to learn learn learn, take her apart, refresh and get back on the road.
I started my list and will keep adding as I go along.

Thanks in advance for all your help.

 

if its overflowing out of the carb boots , then one or more of your carb float needle valves is stuck.
try tapping on the float bowls, with the plastic handle of a decent sized screwdriver to see if you can dislodge a stuck float or some grime on the needle.
this is where your overflow problem is.
yes you can run the setup you have with the dummy tank, its best to put an inline fuel filter between the petcock and the carb inlet, to stop grime from entering the carbs.
if the screwdriver trick doesn't help, then its a case of removing the carbs and float bowls and cleaning the float needles and seats.
have you read "The church of clean" sticky info, about carb cleaning
Clean Your Own Carb's - The Whole 9 Yards - by: Rick Massey | XJBikes - Yamaha XJ Motorcycle Forum

 

Thanks bensalf, will give that a try. Scared to run the experiment again as too much fuel spilled on driveway.
BTW, this is what I was using:
MOTO4U Auxiliary Gas Fuel Tank Universal Motorcycle Gas Tank Repair Tool Kit Gas Container Auxiliary Fuel from Amazon.

 

does the dummy tank have a stop valve on it? if not , install one ,then just keep turning it on a bit at a time, if it overflows then , turn it off and you wont have the half litre spillage.
also :-
IN THE CHURCH OF CLEAN | XJBikes - Yamaha XJ Motorcycle Forum

 

Yes, it does. that is exactly what I was trying to do. In the end, i opened it up a bit, the bike ran on and off, but still most of it was spilling through the carbs somewhere. It all happened fast and in my excitement of seeing the bike run lost track of where it was spilling out. Yes, I started reading through the article, it will take me a couple of days to go through it slowly and understanding all the terms, trying to picture all parts, etc. Lots of good information for sure.
Thanks again for all your help.

 

Update:
Tank has been soap rinsed about 2-3 times. Drywall screws (140) put in and shaken the hell out of it with more soapy water. Rinsed thoroughly, removed all 140 screws, then treated to a vinegar soak over 3 days. Baking soda rinse and finally water rinsed and shaken about 10 times until no more rusty flakes came out of the tank. Long process but if you watch some videos, it's well worth it. Sprayed some fogging oil in it and made sure all surfaces were covered.
Next, I took the petcock apart. It was full of grime and rusty bits everywhere. I can't understand how it got to this stage but dremelled the sh..t out of it until all openings were nice and clean. For reference, there are two openings, one is the fuel supply (large one) and the smaller brass one is the vacuum line. Once everything was cleaned up, checked the function of the petcock and all working as it should.
PRI, gas flows freely through the fuel line.
ON, no gas leaking unless the vacuum line functions, this is normal when the bike is running. You can test this by creating a bit of suction through the vacuum side.
RES, no gas leaking unless the vacuum line functions, this is normal when the bike is running.

Tank and petcock back on the bike, tried to start but no luck. She will run for a bit on starter fluid but not on her own.

Today I decided to go for it. Removed/loosened all brackets around the boots
Removed the airbox boots, forced them gently out of the air box.
Removed choke and throttle cables
Then saddles the bike and pulled forcefully but gently upwards until the carbs got lose from the boots close to the engine block.
Carbs are out.

Now, how the hell do you remove the airbox assembly? Clutch cable also disconnected even removed the stator/started but for the life of me can't get the thing to come out. It's full of mouse ppooppp and wanted to remove the whole assembly to give it a good clean before looking at everything else.

 

One more post and I guess I can post some pics.

 

BTW, in my first post, I had mistakenly connected to the auxiliary fuel line to the vacuum port on the carb rack. This is why all the fuel leaked out of the carbs.
Probably got fuel in the oil tank as well so will need an oil change as well.

 

It is not possible to remove an intact airbox without removing the engine from the frame. I think there have been some who claim to rotate the engine forward a bit and get it out but I don't think so. I don't think it is worth it to do all that unless you are looking to do a perfect restoration. An entirely adequate cleaning job can be done without removing the air box. Your shop vac will not be pleased however.

 

LOL that's right. I did notice there was a long tube connected to the bottom of airbox but I see no hole where this is connected. was thinking to rinse it out that way.

 

The long tube at the bottom doesn’t connect to anything.. it IS an airbox drain.

 

Welcome to the forum. Love to see some pics of the tank after you put that work into it. Using a hot air gun or even a hair dryer on those boots will help them be more flexible. When you clean them carbs, take your time, really make sure all the jets are clean and that the "O" rings are in good shape. You know how fun it is to take out and put in them carbs. So, do it right the first time, and you will only have to do it once. Or so the tail goes. Never happens to me, I seem to miss something each time.

 

Thanks Timbox.
Yes, forgot to mention after it was rinsed out completely, I added a quart of alcohol and swished it around to neutralize the water. Then hairdryer for a good 10 minutes or so until the entire tank was bone dry.
A bit of flash rust started developing but then I sprayed enough fogging oil to form a bit of coating everywhere. Turned it around a few more times to make sure all inside areas were covered.
I could still see very small pieces of rust in this fogging oil so I will have to clean out the petcock again and definitely install an inline fuel filter before I reinstall the carbs.

I'm currently reading through the Church of Clean post and will follow it religiously. Hopefully it will all make sense once I start working on it.

 

@hogfiddles, I will check it out again, one end is connected to the bottom of the airbox, the other hangs out in the open under the bike.

 

That is correct. If the airbox gets water in it, or gas floods it by either backing out through the carbs or filling up the crankcase and coming up through the crankcase vent tube, it will simply run out the drain at the bottom so that the airbox doesn’t fill up.