Early 85 XJ700 Maxim Carb rebuild issues/questions need HELP

My first post to this forum:

I just pulled a 85 XJ700 Maxim out of a barn after a sleep of 22 years. 1400 original miles and some oxidation and rust but all there.
I am pulling the carbs apart and see a MAIN NOZZLE on the diagram.
I did not see any way to pull that MAIN NOZZLE out of the carb after removing the MAIN JET. Did I miss something?
I finished the first 3 carbs and dipped them and put them back together. I am waiting for new gaskets and float needles. 4th one is in the dipper right now. The needle on this one was so stuck that I had to gently tap it from the bottom. Well, I bent the tip. When I tired to bend it back, it snaped. I shaved it down to a point, but I think I need another needle. They are no longer available.
I also do not see any air/fuel mixture screw anywhere.
And what are those 4 short hoses for? Way too many hoses on this bike.
One for fuel supply (center). 2 long ones for drainage?
four short ones for ???
Any help here would be appreciated.

 

Re: Early 85 XJ700 Maxim Carb rebuild issues/questions need

I'm not sure exactly what you did or know so I apologize if I get too simple.
So, you pulled the needles out the top (with the diaphragm attached). There was a big spring under the cover holding them down correct?....darn, where are the photos when you want them?

Anyway, those needles slide down into the emulsion tube. This is the main source of fuel once you get off idle. There is a Jet that screws into the bottom of the emulsion tube. Take a GOOD proper fitting screw driver and remove that jet (and the washer underneith). I like to screw the jet back into the emulsion tube without the washer and give it a little tap with the screw driver HANDLE (read>soft plastic). It may take a couple whacks if it's really stuck. If it don't move, get some PB blaster and let it soak. They have been waiting for 22 years, a day of soaking wont hurt.
There is another jet just behind it (same size but smaller hole). Carefully remove that also.
There are two jets up on top under where the diaphragm was. One is probably a #240 and other is a #70. Take those out and make sure they are clean.
Then you have the float needle seat with a little screen on top to clean.

Personally, I like to pull the choke plunger and make sure that's clean.
AND the fuel mixture screw is right in the center on the top. It probably has a soft washer covering the hole. There are a couple tricks to getting it out safely.

Do some searching on here for all kinds of carb cleaning write ups and good photos since a picture is worth a thousand words and I may have had a couple too many beers tonight!

and YES, you will need a new needle. They are precision parts and even a little ding can affect function. Len (xj4ever) will have them I bet otherwise I'm sure someone has a parts carb they can sell you.

Edit: Here are a couple good reads:
http://xjbikes.com/Forums/viewtopic/t=2 ... aning.html
or here
http://www.xjbikes.com/Forums/viewtopic/t=18016/
and all kinds of good links on this thread
http://xjbikes.com/Forums/viewtopic/t=1 ... aning.html

 

do exactly what designer mike says and you will be fine. Mike did you know the float bowl screws are the same thread as the jet that's what i use to tap the emulshin tube up
Make sure the diaphragms have no cracks or splits in them. There is a brass tube that goes into a hole in the float bowl that picks up fuel for the enrichment (choke) there is a small hole in the bottom of the float bowl that feeds the pipe make sure it is not plugged. When you put your floats back in make sure you wet set the float level before putting carbs back on the bike. If you disassemble the carbs from the rack to clean them. You will need to bench sync them also. last thing if your going to soak your carbs do not submerge them as hi as the shaft with the butterflies on them or you will have to replace the shaft seals. You probably know this but thought i would say it just in case you didn't better safe then sorry

 

The Nozzle is a loose "Press Fit"
Remove the Main Jet and Washer.

Insert a Metric Allen Bolt with the same Thread Pitch into the Bottom of the Emulsion Tube.
Tighten it Finger Tight
Tap on the Cap Screw and DRIVE the Nozzle OUT through the Top.

For Mikuni Carbs:

When replacing the Nozzle.
Insert the Nozzle into the Carb Body wiped with light Oil.
Press the Nozzle into the Body and insert the Cap Screw into the Threaded Bottom.
Rotate the Cap Screw and Pull the Nozzle into position when the Slot and Keyway align.

Pull on the Cap Screw and Press the Nozzle in from above until seated.
Remove the Allen Bolt and replace the Washer and MAIN Jet.

Remove the Stuck Diaphragm Needle, Nozzle and all, ... together.
After you get the Nozzle, stuck Needle and Piston Assy removed together,...
SOAK the Nozzle until the Needle becomes free.

Carbs that have Diaphragm Needles stuck in the Nozzles (Emulsion Tubes) NEED to have ALL ... >> FUEL << ... and ... >> AIR << Passages:
Probed
Flushed
Blown-out with compresses air.

((( Especially the MAIN AIR PASSAGE )))

 

roehlerich what did you dip the carbs in?

 

Rick - You need to write your own Tech manuels you can follow your directions even without pictures.

 

Thanks to all for the info. Here are some answers:

I bought a 1 Gallon Carb Dip solution from Advance Auto Parts.
Works great. I have blown out all the passages but will check that little tube in the float bowl again on all.
I do not have Mikuni Carbs according to the guy I ordered the gaskets and float needles from he ran my build date 1/85.
So I guess there is a Nozell where the needle slides in (Emulsion Tube). I will tap that out from the bottom to the top with a screw and a slight tap.
I did make sure that the idle jet is clean. Little guitar wire. Was a bear but so far the first 3 are good.

I do need a needle or two since I did had to tap them out from the bottom already. This is not my first carb job, but clearly I am over my head on this one. Never seen anything this dirty and stuck before. All the butterflies did not turn. Now they are all fine. I did dip the body completely. I guess we will see if I need all new seals. I did replace all the rubber on the T-connectors and connecting tubes.

I am still not sure where the air/fuel mixture screw is. I am looking at a diagram from a parts place that has all the carb compnenets listed. Can't see it.

ANY help here would be appreciated.

 

If you have Mikuni carbs, then you have a completely different jet set up than what I originally (attempted) to describe.
AND, you would have a XJ700X (the water cooled version)

Good news....I have about 4 racks that I could easily spare a needle or two from!
Bad news....Most of the photos that you find here are for the hitachi carbs. I'll drop you a PM with my email and I can email some direct if you want.

IMHO, don't even bother putting them back together without changing the throttle shaft seals. You'll be kicking yourself every time you try to sync them and she doesn't run right.
You can either get the proper seals from Len (XJ4ever) or I found some metric orings that fit....it's much preferred to get the proper seals from Len though.
BEWARE though>> The butterfly screws on the mikunis are peened over on the back side. You need to file them flush and then make sure you have the right JIS screwdriver to get them out. I actually tap a #2 phillips into them and use my impact driver to remove them but you need to support the shaft when you do that. BE CAREFUL it's very easy to strip that damn little screw and then you are a "helically wrapped incline plane". Then the butterfly needs to be perfectly in the center of the throat to get it to slide out. Don't force it or you will bugger up the edges.

The Mikuni carbs have a "indexing pin" on the emulsion tube just below the jet so pay attention to that when you tap them out.

PM sent

 

Thanks Mike for the info. Mine is not water cooled. I do not think that I will take the butterflies out and replace the seals. That is just too much work for a rusty junker. I like tinkering, but it does have it's limits. I appreciate the offer for the needles. I replied to your PM.

We now have a problem. The little hole in the float bowl that feeds the choke valve tube is clogged. Soaked the bowls over night and still no go. I am in there with wire and a small drill bit by hand. Still no go.

Thanks to all for the excellent links and advice. So much to read, so little time.

 

DOPE (in homer simpson voice)...I thought you said "I DO have Mikuni carbs"....but you said I do NOT have Mikuni!
My bad.
Sorry....strike some of that commentary then!

 

Partial success. I drilled out the bowls with a 1/16 drill and now have free flow up to the choke valve.

 

Since you had a Needle stuck in a Nozzle, ...
Once you get them Nozzles all out; Clean them one be one.

There may me more than 20 tiny AIR Metering Ports drilled through the Nozzle.
Probe through them and hole them up to light to see through them.

Twist 3 Pipe Cleaners together and scrub the Center Tube.

Use a Guitar String and Probe the tiny hole in the BRASS Siphon Tube that extends into the Fuel Bowl well.

 

Yes, I got the first two Nozzles out and cleaned them out with guitar string. Good tip about the pipe cleaners. I have to do the other two next week when I get the gaskets. I don;t like getting things mixed up and have little space on my bench to spread stuff out.
I ordered a needle from Fleebay today for a 83 XJ750 or 650 hope that this will fit my carbs. Can't find needles anywhere. One of mine just has the tip missing because I hit it too hard trying to pull it out.
Now I know to push out the Nozzle. Learned something again in this project.

 

I believe the 1/16" bit is really too big, but I'm not sure how that will affect it. I believe you will get too much fuel if you open the choke but others can chime in on that experience.

Len has the "proper" size bits but it's too late for that.....worse case, you need new bowls and I believe they are the same on almost all the hitachi carbs for the XJs and should be a dime a dozen at any salvage yard.

 

I've had the same problem with the holes in the bowls before. However, I have found that if I leave the bowl in the dip for several days it will clean up. I had to leave one bowl in for almost a week before it finally cleaned out. Now the bowl is nice and clean. I would NOT recommend that for the rest of the carb. some of the parts, yes, but other parts, no.

That was also a carb rack that was absolutely black crusty blobs w/no visible brass at all. now the carbs are nice and clean. worst case scenario was that if it didn't work, I wasn't out anything anyway....they were that bad. Not anymore

Dave

 

Because you had Fuel so-far-up the Nozzles that the Needles got Stuck, ... this might indicate that the Bike spent a long time "Leaning-over" or "Laid-down".

If this is the case, ... there might be residue accumulated on the inside of the Fuel Supply Gallery -- connecting all the Carbs.

If the Beenie Screens on the Float Valve Seats are coated with residue, ... it would be advisable for you to:

Remove the No.-1 Carb from the Rack.

Use a Test Tube Brush or a Small Caliber Rifle Bore Cleaning Brush to scrub the Fuel Distribution Gallery and Connections free of any hardened varnish-like film deposits that might flake-off and cause trouble later-on.