650H 1981 - Carb Disassembly Isue (of course!)

Hi all,

OK, I'm at this step of Rick's good "Whole 9 Yards" (FAQ Section) for carb disassembly and cleaning:

On the high post is the Main Jet.

Wipe off the bottom of the large Main Jet. Read the engraved numbers on the bottom of the Main Jet and write down what that number is in your Note Book.
There is a copper washer that the Main Jet holds in place.
Remove the copper washer and store it with the Main Jet, in the next bin up...

AND -- When I turn out the main jet to remove it from the bottom of the high post, the jet and the washer turn and turn and turn and turn and turn and turn (fairly easily, and, yes, counter-clockwise), but THEY NEVER COME OFF THE POST (this is only for carbs 2 and 3 -- 1 and 4 came off perfectly)??

What is going on under there -- why wouldn't they have dunscrewed from the emulsion tube w/in the post to release? (it is an "emulsion tube in there, yes?)

And what the heck to do about it?

Thanks in advance

 

Somebody has managed to shear off the little locating "post" that keeps the emulsion tube from turning.

You're going to have to hold the emulsion tube to keep it from turning; not having had this issue with an Hitachi yet I'll defer to someone who has...

 

Thank you Bigfitz,

Your post was very helpful and got me "off the dime" -- unstuck -- Here's is what I had to do:

Of course I sacrifised both emulsion tubes, and assumed (as I thought about what to do) that I would in fact have to bugger them up to "hold them" to get them out... I looked around my shop and while I have a few left hand screws (something to go into the open, piston-end of the carb to "hold" the tube while I apply counter clockwise pressure on the Jet) I had no left hand-thread screws of the right size -- so, I looked at the end of both shears of a pair of scizzors and realized that the cutting-edge of both sides of a scizzor bevel in opposite directions -- and they taper -- so I selected the blade that would "bite" into a counter-clockwise turn and put it carefully down the piston-opening and while applying tremendous pressure on both the screw driver (on the jet) and on the scizzor blade (being careful to keep it centered so I don't score the piston-shaft) -- I managed to break each jet from the emmulsion tube -- buggering the top of each tube, but getting all out safely otherwise.

Now, I've been VERY thoroughy staring at the the emmulsion tube both ends and the carb body-tube in which the tubes are set and I see NO indent or retaining notch etc.

The "good tubes" that did not have an issue (carbs #1 and #4) don't give any hint either of a holding tab or indent into which the tubes is slotted to "hold" it against the torque of the of the jet when it is screwed in?

So I don't understand this? What is SUPPOSED to prevent the emmulsion tube from spinning?

A huge thanks again!!

p.s. of course they were essentially seized but with out a slot or a tab into which the emmulsion tube sits, I would think this a regular occurrence on disassembly... I have not reassembled carbs like this, so I am wondering what will provide the resistance for the jet screw when I put them back together? Maybe the seat holds 'em well enough when the threads are fresh and lubed?

 

"I had no left hand-thread screws of the right size" i'am surprised you had ANY left hand screws, i know i don't
you could have pushed on the top of the tube with a wooden dowel, or grabbed the little bit sticking up with needle nose pliers and not killed them.
i doubt there's going to be any problem putting them back in, use a dowel if there is

 

Thanks, None of it (emulsion tube) was "sticking up" to grab with a pliers, they were siezed tight at the jet end -- they were pretty well siezed, I didn't try a dowel, but a tried my fingers -- I don;t think a dowel would have held it -- RE: LH Screws -- I have turnbuckles for robot and aircraft servos - one side RH the other LH but none large enough...

The scizzor blade acted like a tapered LH thread and really dug in till the jets broke loose... well, Len's got a large order coming, so these'll be tossed in

Thanks all

 

Hey coach, both side of a pair of scissors are exactly the same.

 

You're right! However, both sides cut against a CCW turn and worked well

 

If I recall correctly, the Hitachi doesn't have a locating pin like the Mikuni. They're a friction fit.

first I've heard of this problem.

 

My '83 650 has friction fit on it's Hitachis. I'm glad you mentioned this, i was starting to worry .

 

The easiest way to remove and replace Emulsion Tubes is to use a Metric Cap Screw of the same Thread Pitch as the Main Jet. (Common.)

On both Hitachi & Mikuni:

Remove:
Screw the Cap Screw into the Bottom of the Tube,
Drive it straight-out.

Install:
Screw the Cap Screw into the Bottom of the Tube,
Lube and Insert into Carb Body
Grab Cap Screw and PULL into place.
(Mikuni)
Rotate Cap Screw while pulling Tube into place until Slot and Key align.

 

I have an 82 Maxim 750 with the Hitachi Carbs and this is my first venture into rebuilding, extreme newbie, however relentless! When you say drive the emulsion tubes, do you more specifically mean put a screw where the Main Jet goes and smack it "UP" through the Cylinder of the Carb? Tap the new dummy screw with a hammer until it slides up? and what about reinserting, does it need to face a specific way for the air and fuel to mix properly?

 

Prepare for the NEXT time you'll have to Clean Carbs and start a collection of "Tools" which make the job a bit easier.

Buy a Cap Screw that is the same Thread Pitch as the Threads in the Emulsion Tube.
Remove the Main Fuel Jet and Washer.
Insert the Fastener you bought.
Gently Tap on it, ... Driving the Tube up toward the top of the Body.

Once the Tube is loose from the Pressed Fit, ... remove the Fastener.

Use the Fastener to Install the Tube once cleaned.
Start the Tube into its space.
Insert the Fastener and Pull the Tube down in Place.

::: TIP :::

You can use a Nut and Washer to "Draw" the Tube down-tight.

Save the Fastener for Next Time.

++ MIKUNI CARBS ++

Use the Tool to ROTATE & FIND where the Slot lines-up with Key.