XJ650 Hitachi Carb Pics - VERY PIC HEAVY

Had 5 sets of these puppies in bits at once recently so clicked off a few shots...







































Here's something you don't want to see...

 

Green carbs!.

 

Wait till you see what they look like cleaned up 8)

I'm guessing thats the result of leaving gas and what ever else was sprayed in to them, sitting for a few months on the brass

 

Nice thread alive, the pics will be very useful for future questions. it might not be a bad idea to put this in the FAQ section

 

Alive, on a couple of those pictures it looks like one of the posts that holds the float rod in place has been repaired. Do you know if that was done (or can be done) just using something like JB Weld?

Oh, and wanna send some of those jets on a sea/air voyage to Texas?

 

Yes it has been repaired and not a bad job either. The post is exactly where is should be which would have been hard to get right. Know anyone that's good with a TIG welder?

Thing you have to remember is that these posts are soaking in gas all the time. Would JB weld be able to handle that? At the end of the day the post is just a holder of the pin, therefore as long as it's secure and in the position it's ment to be in, you should be good to go.

Are the Jets that hard to get?

 

Were those size 45 pilot jets what came stock in your bike? I'm in Canada and my bike came with size 43 pilot jets and the US bikes have size 40 pilot jets.

 

Yes they were stock in 1 of the 5 sets I have.... Needless to say that's the set going on the chop

 

Just to verify that what I think is true is really true:



Is this correct?

 

Yes, you are correct.

 

Give that man a COOKIE!!!! ;-)

Alive, I don't know other peoples experiences, but based on my own, yes it is THAT hard to locate the jets for these things. I think I have found a source for all of the stock jets except the Pilot Air Jet. That one seems to be nowhere to be found. Too bad I don't know how to machine parts up. I'd go into business supplying jets to XJ owners.

 

What I'd like to see is something that points out all the various passages inside the wee beasties. When I had mine apart (I didn't have any plates, either -- on the bike nor on the spare set I have) I tried to blow out all the passages, but I'm not sure I got them all. I'm not even sure where they all are. :?:

 

Here is a cross sectional view of a Hitachi Carb.

Richard
-----------
1985 XV700 Virago
1980 XJ650 Maxim

 

Now *that* is something I'd expect to see at a Carb Clinic. Now you need some classroom chairs, a blackboard...

...but isn't the pilot screw supposed to be on top, instead of on the bottom like the picture shows?

 

Yes ...

Also missing:

Enrichment Valve
Fuel Bowl Well and Siphon Tube
Upper Body Air Jets
Intake L/R Air Jets

 

So, it's like a really great diagram but almost totally wrong?

Must be from a Haynes manual............

 

Yes, but them there is probably a cross section of Hitachi carbs from something like a Kawasaki GPZ750 which do have the mixture screw underneath. Ain't no two carbs alike it seems.

Nice pics Alive, Now I see those jets and plates that these poor Hitachi owners keep talking about.

Alway been a Mikuni man so never played with Hitachis. Ain't I lucky :lol:

 

Hi guys, just a question. I have bought and replace the float needles on my Hitachi carbs for my XJ650. i am having problems running it (that is another story, will sync and colortune shortly). My question is this:
The ones in the carbs before were brass and the ones I received were silver Are they the wrong ones? Bought them from PartsNMore.com
Thanks

 

johnt:

Use "New Topic"

Float Needle Identification

Restate the question so others know to look.

 

Sorry, turns out that is a Hitachi from a 700 Virago. I thought I had pulled down the XJ as well.

 

Thanks RickCoMatic. Done, thought it was relevent in this thread.

 

I've uploaded two pics scanned from my Yamaha Factory Service Manual showing both an exploded and sectional view of the Hitachi carbs...

EXPLODED VIEW

​

SECTIONAL VIEW

​

Hope these help.

(Note: Pictures are for educational purposes only. :wink: )

 

The exploded view is correct and can be used with confidence.

The sectional view is "almost" correct but is missing some key components, starter jet circuit, etc. It should only be used as a rough guide.

Why on earth Yamaha published incorrect carb sectional views in their factory service manuals is almost inconceivable to fathom. You would think that someone, somewhere along the line (in 25 years) would have caught that and corrected it.........

 

How important is this plate covering the jets ? My carbs have them missing and seems fine. So I am not sure of their purpose.

 

What those Cover Plates actually do is debatable. Some people believe that it regulates the flow to the Main and Pilot Air Jets making the application of power smoother.

Others thing that it there to help regulate the collapse of the Diaphragm from being "Pulled stronger" from the one side.

I have seem more Carbs without them than with them. I think there must have been a point when it was advised to remove them.

Since they don't redirect FUEL, and the Bike's without them seem to have a little easier time Pulling at 4,000 rpm's and above ... I think you can experiment leaving the in and taking them out and determining for yourself which works better for you.

The Consensus among those servicing Carbs is: "If they are IN there when you get there ... leave them IN. If they are gone when you get there, don't put some back-in thinking you are making a correction"

Don't make the mistake of not taking it off and looking at the placement of the two AIR Jets beneath the Cover if you have bought "Recently Cleaned Used Carbs."

Those two AIR JETS below that cover are the two that are inadvertently mixed-up if they were removed and replaced according to the SPECS for Jets in the Haynes Manual.

The MAIN (Air) Jet and the PILOT (Air) Jet are Opposite from FUEL Jets.
The MAIN (Fuel) Jet is the one with the Larger Metering Port.
The MAIN (Air) Jet is the one with the Smaller Metering Port.

 

I can't take this, those picture are offending and nasty I refuse to look any further.

 

I think I've read that between 81 and 83 two kinds of carbs were used: Mikuni and Hitachi.

Is this true? Is one manufacturer better than the other? How do you identify them? Mine look as above so I guess I have Hitachi.

 

Sushi, the Hitachi carbs have like a compass logo stamped in the body. I heard that the Mikuni's come with MIK or MIKU engraved in the body.

 

That ... plus:

The Hitachi's have a little "Ramp area" on the Carb Top Cover with the the Diaphragm Spring Centering Spot indented down into the center of the Top Cover.

Mikuni's Top Covers are round. No Ramp area. Spring Locating Center raised.
Miluni's Jetted differently from Hitachi.

 

Mikunis on my 550's have "Mikuni" cast into the right side just below the flange where tha hat screws on.

 

Are the Mikuni's better or are both brands finicky?

 

Let me see if I get this right.
Mikuni's came on the 550 and 900's
All others got Hitachi's.
So there really isn't a choice to be made.

 

Ahhh...now I understand. I was under the impression that at some point, each brand was used on 750's.

 

Mikuni carbs were also used on the XJ700-X and XJ750-X (both are water-cooled engines) models, and on the XJ650 Turbo models, and the XJ1100.

Hitachi's were used on all XJ650 models (except the Turbo), all XJ750's (except the X model) and XJ700 non-X (air-cooled models).

 

First of all, first time posting so hopefully posting in the right spot. Second, love the forum. So much information on here, its been invaluable to my build(xj750). On to the topic at hand. I'm rebuilding the carbs off my bike and getting everything super clean. For some reason i cant get this passage on the bowl clear... I'm assuming it should be?
Thanks.

 

Buy the Drill Bit from chacal.

First: "Manual"

With the Drill mounted in a Miniature Chuck (Craftsman) and a Rubber Hose for Grip, ... Use the Drill as an AUGER and attempt to clear the two Metering Jets which allow the Well to Fill-up.



Second: "Drill the Passages"

If you Drill the Passages, ... MEASURE.
Hold the Drill up to the side of the Fuel Bowl.
Set the -->Max<-- DEPTH and MARK the Drill Bit.
WRAP the Bit with Masking Tape at the Mark.
Slip a POP RIVET WASHER onto the Bit and Stick it to the Tape.
The Washer will PROTECT the Tape and PREVENT the Drill from going beyond the Marked Depth.

::: Tip :::

If you Drill a hole through the Fuel Bowl because you failed to set the Depth of the Drill ... Peen a Copper B-B into the hole.
Heat and Seal with:
a) Dura-Fix
b) Tix Solderr
c) Low-temp Silver Solder

 

I believe the enrichment circuit brass pickup will draw fuel from that well... There is a tiny hole at the bottom... I'd soak it in carb cleaner over night then follow the instructions in the Church of Clean... among great advice on cleaning is a flashlight trick to see if/when it becomes clean

 

Hi fltrey.. here's another another good bit of info' on cleaning th 'enrichment circuit'
http://xjbikes.com/Forums/viewtopic/t=8918/

 

Awesome! Thanks so much! I'll let them soak over night and see if that will do the trick.

 

Mine are soaking and almost ready to be taken apart

 

Eco, did you break the rack and dis-assemble them before soaking.

 

If the Enrichment Well Metering Jets are clogged, ... don't rely on soaking to unclog them.

Don't waste time.
Use a Drill Bit and auger your way through the clog.

CHACAL has the Bit.
But, the 3 Smallest Number Drills are handy tools to have for Jet and Metering Port cleaning.

 

This necro'ing has gotten bad lately...

 

I think it's a combination of "slow news" since it's off season, and rookies.

But it sure has.

 

I think it has a lot to do with the offseason

 

OK looking at top or hat side of your Carb you have a cover over the two jets there under the diagram for some reason. I do not have this on any of this on my carbs is this a problem?

 

that is discussed if you read through a bit the cover was put on some not on others and it doesn't seem to matter one way or the other. So if you have them leave them if you don't no big deal. just make sure it is the same across the rack.

 

OK on phone.trying to read not getting everything

 

Even though this is an old post it has a perfect picture for my needs. The 1st picture on the 1st page has a rack of carbs. The #2 carb has a recessed screw next to a sliding plunger for the choke. The other carbs seem to have something covering those screws. What is that screw called and what does it do? I have a manual but it's still playing hide-and-seek from me since my move.
Nervously awaiting any comments...

 

That is the pilot mixture screw....it adjusts the ratio of air/fuel mixture.....the other three look like they are covered with some sort of plug ( could be a pencil eraser in the other 3...hard to tell )