xj550 carb woes

as stated in an earlier post had petrol flowing out of air filter box ,so took off carbs ,set them up on bench and connected petrol supply found one carb that was over flowing, so stripped it down and replaced o ring on the valve seat and reassembled it, hey presto no leaking carb after 24 hrs so put back on to bike and turned on petrol and it was pouring out from carbs ,any suggestions as to why.if a float sticks would this cause petrol to gush out, carbs are back on bench,without doing anything to them with petrol connected and no leaks?

 

If a float sticks it doesn't stop fuel flow and it will then "gush out."

I suspect you need to do more than replace the o-ring on the outside of the valve seat. Remove the valve needle, inspect the rubber tip and the inside of the seat. Make sure the seat is clean and smooth and the rubber tip is in good shape.

It sounds to me like one or more float valves is hanging up; usually this happens because of gumminess or dirt/debris in the valve/seat.

 

whats the best method to take out the pins on the floats as they dont seem to want to budge at all,would carb cleaner be much use on the needle valves?

 

I had to break my rack, put a socket under the towers and then use a punch and hammer and almost gently tap tap tap tap tap, and then I think I tapped some more. Just be careful not to break the towers because they break rather easily I'm told.

 

There's a "secret" to the Mikuni float pins:

The "bindy" part is a "fat area" just under the HEAD. The "long end" of the pin just slides into the opposite tower.

Take a REALLLLYY close look at the float pin in the first pic here: http://xjbikes.com/Forums/viewtopic/t=31061.html You can just barely see the wider area of the pin just below its head.

I have a nylon block I use for all sorts of stuff with a hole drilled in it. All you need to do is support the tower where the head is and tap gently with a pin-drift (or nail setting punch) on the free end. They pop right out.

No offense to the Hitachi sufferers amongst us (and I'm one as well) but the Mikunis are much more of a precision instrument than the Hitachis and require a lot less brute force, instead rewarding precision.

You need to become a carburetor dentist to successfully work on Mikunis. Get them right and they seem to hold their adjustments much longer. But one must be meticulous.

I love 'em.

 

Dude! Where the heck have you been? Fixed the bike so now you don't wanna play any more?

I just got back from a 30-mile honk on the '83.

Thanks for the close-up. Dig up your thread on butterfly removal and bump it or re-post it in "FAQ Suggestions" (if it wasn't there to begin with.)

Don't be such a stranger. I like having experienced backup.

 

Any chance this would work to get the float pin removal started? - then finish the job with pliers

http://www.ebay.com.au/itm/New-Heavy-Du ... 438wt_1162

 

Haha! My bike is together. I've even got a few new customizations that I'll share when I get a moment. Fuel filter, bowl drain screws. clutch rattle reduction.

I've put more miles on her in the past month than in the past two years. Granted... That's like 30 miles. I've got to get my state inspection done and after that I'm hoping to put on a respectable amount. First time in a while I'm feeling up to the vibrations in the saddle.

I've never been prolific, but I'm here if you need backup!

 

I wouldn't do that. You really need to support the head end post while applying any force.

 

Agreed. Bad idea, and it won't fit. Adrian1, don't you have Mikunis on the 900?

"Clutch rattle reduction" can be accomplished with a sewing-machine smooth idle from an accurate vac sync. I was marveling at that this evening when I got in the driveway; I was playing with the "clutch in/clutch out" sound while it sat there idling as smooth as they're supposed to, at 1200rpm.

I love my XJ. Various factors have kept me from commuting on it like I used to be able to; but that makes the weekend and "day trips" as well as long evening rides all that much more rewarding. But then again, I'm the guy who gets home from a 60-mile commute and then goes for a ride because it's a nice evening.

 

Stuck Float Hinge Pins can lead to a catastrophe.

The method suggested by Veteran Member MiCarl is to use a Spring Loaded Nail Set Tool.

http://www.amazon.com/SpringTools-32R12 ... B000FK3W0U

I use a pair of Diagonals I have doctored-up for the task.

I flattened the back-side of a pair of Diagonals.

First, ... I use an old Boy Scout Jack-Knife.
I use the Blade and a Small Ball-peen Hammer Head to wedge some daylight between the "Head" of the Pin and the Float Pillar.

Then, ... I use the Dikes and increase the Daylight by grabbing further up the Jaws until I can grip the Pin and make t rotate.

 

I understand what you are saying but I was thinking the jaws would embrace the support pillar (as it does with the chain link). No? Bigfitz yes I have Mikuni's. Not sure what you mean by "won't fit" are you referring to the diameter of the chainbreaker pin?

 

Chain-breaker ???

No way. Guys.
I don't know how much force it takes to Fracture a Float Pillar.
My best estimate, ...
LESS than you think . Alot less.

One way I tried before ruining a Float Pillar was this.
Make a Pin Punch.
Grind a shortened Nail to use as a Pin Punch.
Harden the Business-end. Heat. Quench in Oil.

Use a "Steady-handed" assistant.
Discuss the mission and Float Pillar precautions.

Using Heat, Your New Punch, Assistant*, Needle-nosed Vice Grips and the Head of a Small Ball-peen Hammer (No handle).

Mount the Vice-grips Lower Jaw section in the Vice.
Have good light.
Align the Inside of the Float Pillar in the Jaws of the Vice Grips.
Close the Jaws enough to Support the Inside-Pillar.

With the Inside of the Pillar supported by the Grips acting as a Jig, ... Heat BOTH Pillars.
When you BOTH are prepared and carefully positioned, ...
Use your handy-dandy Tool and Hammer-head to persuade that stubborn Hinge Pin out.

Pretend you're the Bomb Squad and need to get that Pin out without damaging the Pillar to save the World.

Last gasp?

Cut the Float Hinge exposing the Pin to be grabbed and turned.
Broadcast A-P-B for a spare float.

 

You need push on the tip of the pin. No problem... That device will do that. Problem is that while you push on the tip, you need to support the pillar at the OTHER END of the pin (the head end). Unless I'm misunderstanding just how wide that device opens up, I don't think it's anywhere near wide enough to reach around the near pillar to support the far one.

Am I underestimating the capabilities? :?:

Here's a thread with some other ideas:
http://www.xjbikes.com/Forums/viewtopic ... +head.html

 

Ok I see your point about 2 pillars! For it to work safely you could use kroil on the unsupported pin and very gently turn the screw and "maybe" you'd get away with it...but i think there are other safer ways to skin a cat! Anyone ou there with an unwanted carb like to test it? :wink: I don't like the tap tap tap approach....Instead like sex, slow and easy :evil:

 

You don't get it.

The pillar you need to support is the one by the HEAD while you push the end of the pin which is presented at the OTHER pillar.

Any sort of screw-type pin pusher would have to be long/deep enough to support the opposite pillar while pushing on the pin. The pin is NOT being bound by the free-side pillar, just under the head. There is no need to support the pillar at the end you're pushing from.

All you need is a block of wood or the like with a hole drilled in it to support the head-end pillar "around" the head whilst applying a quick tap to the free end. They pop right out. Look at the close up pic of the pin. There's not a whole lot of binding going on considering the minor difference in diameter.

 

Ok I see what you're on about re the wider end of the pin - agreed. Obviously those that have broke their posts have tapped away without supporting that post.

 

Or they were working on Hitachis. I can't recall that many Mikuni sufferers with broken towers, although I'm sure it happens.