Carburetor jets - this can't be right

I'm the first to admit that I'm no expert here. I picked up an XJ700 Maxim with no history, cheap. The carbs are off of the bike so I thought I'd at least pull them apart and do some cleaning. First, I was surprised to find that they appear to have jets in both the top half and the bottom half but, as I said, I'm no expert.

But the jets on the bottom don't even match from carb to carb. Three of the carbs have one each labeled "107" and "365" but one carb has two labeled "365." That can't be right, can it? I'm not actually sure what I should be finding here.

 

The 3.65 fuel jets are for the pilot mixture circuit (the shorter tower) and the #107's are the main fuel jet (taller, central tower, with the copper spacer washer under the head). And maybe it's the angle of the picture, but the one you have labelled as a "365" on the left carb in the main jet position sure appears to have a big hole in the center, it can't possibly be a 36.5 jet (the numbers represent millimeter, a 36.5 fuel jet is 0.365mm diameter, a #107 jet is 1.07mm diameter, etc. BTW, the AIR jets (on top of the carb, under the rubber diaphragm, do not follow this same sizing protocol).

 

Here's a closer image. Not the best, but you can clearly see the markings on both jets.

 

any fool can buy drill bits

 

Yes, but look at the size of the center holes...……...the one on the right in the picture (which is the pilot jet circuit, and should use a # 36.5 size jet) is tiny, while the one on the main jet (taller tower) is huge. XJ550H has probably solved the riddle, which of course brings up the obvious question, what else did he mangle while on the loose and armed with a drill bit and other dangerous tools?

 

Other dangerous tools...like the wrong screwdriver for the jets.

Which brings up a point that you will need to take care with. None of the crosshead screws on your machine are Phillips. They are JIS, and a Phillips screwdriver will chowder the heads up just as badly as the PO's crappy screwdriver did to the slots on the jets.


Jets are relatively inexpensive. Get new ones. That fella with the logo for an avatar will have them.

 

You are doing great! Digging in there and doing your own work, that is awesome! You will have to fix those jets, best just to get a rebuild kit and make sure all four are the same. Don't see any crazy green muck or anything growing in them carbs though. Sense you have them on the table, take them to "Church" if you have not already. I would guess by the way the top of the jets look that the emulation tubes are really nasty. That is where all the green and other color muck is hiding. Need to get all the little holes cleaned out for the fuel and air to pass and mix.

Keep them pics coming.

 

Thanks, guys. I'm really new to all of this. Until I decided to build a bobber out of my KZ454 two years ago, I'd never so much as changed the oil or plugs myself, so I'm learning as I go. But it seemed clear, even to me, that those jets couldn't possibly be correct and, moreover, that somebody had mangled the crap out of them with the wrong screwdriver.

 

BTW - is there a way to make sure these are even the correct carbs? I can't find any brand markings - Keihin, Mikuni, etc. - stamped on them anywhere, or any other useful info.

 

A picture of the full rack would be helpful, but those are definitely Hitachi carbs, and judging from the plethora of fuel lines attached to various places, they are probably the correct HSC33 series carbs (only htose Hitachi's had a fuel line explosion such as that...…..). The Hitachi carbs don't have a name/word on them, but they have an odd hexagon logo cast into the base. On the bottom (outside) of the carb BOWLS, there may remain the ID numbers that are ink-stamped from the factory.

 

This little symbol is the only marking I can find.

 

That's trademark-speak for Hitachi.
You have the correct carbs for the bike.

IN THE CHURCH OF CLEAN

Why you should replace butterfly (throttle shaft) seals.

Replacing your Hitachi throttle shaft seals

Setting the fuel levels

Inside your Carbs

Get teh full rebuild kit from Chacal, strip them to bare castings, and give them a good dip in Berryman's (Pay attention to the directions on the can).

After that youcan put 'em back together and set them up.

 

First off, let me say this: I really appreciate all the fast help and encouragement. As I said previously, I'm really new to doing anything mechanical. In the past couple of years, I've joined a handful of forums and groups and they tend to be either dead (*crickets*) or brimming with mean spirits. On the one hand, members complain that not enough kids / new people are getting into the activity and then, on the other hand, mock me for my ignorance when I ask questions that "everybody should know the answer to." New people, by definition, don't show up already knowing everything.

Anyways ... thanks again. I think I'll button the carbs back up until I have rebuild parts in hand. It doesn't make much sense to me to tear them apart if I can't put them back together again until later. That's a recipe for lost parts and other confusion.

 

BTW, that yellow-and-black "headed" type of toothbrush shown in the images above (with the bristles sticking out of the "head" of the brush and an upward angle) is the most useful style to have for cleaning various things, including carbs...…..

 

Mclarkson,
If you have a digital camera or your cell phone with a camera, as you take apart the carbs take pics. When it comes to the orientation of some of the springs and how the throttle shaft lings interconnect it really helps. There are lots of pics on this forum to help you out. I use this method at times when I take apart something and then have to come back to it later on. Just a nice way of having a record of how you took it apart and how you can put it back together. What screws to on the top, to the bottom and even the jets on the front and inside.

Just to emphasize how important it is to get them carbs clean. When I first started working on the XJ's I had to pull a carb rack off six times before I got it right.

 

Well, it may not matter.

I knew the bike had been laid down. Yesterday, I got all the wonky fenders and such off of it, put it up on the center stand, and took a good look at it, trying to decide what direction I wanted to take with the bike.

Instead, I noticed that the frame is bent. Badly. It never even occurred to me to check although it's obvious now that I should have.

I know that’s a minor inconvenience for some people but, for me, I’m afraid it’s a project ender. I’m not set up to repair the frame or fab a new one. I could probably find another frame with a dead motor somewhere, if I put in enough time but, again, this is above and beyond what I had in mind for the project.

So it looks like I’ll be trying to sell it off as a parts bike on CL, or maybe sell individual bits – shocks, mounts, rims, carbs, etc. – on eBay etc.

The saddest part is what a great community this seems to be.

 

No. The saddest part is that I don't have a spare frame to send your way.
There are a few other members in the neighborhood. Maybe one of them will see this and offer up help, or buy the parts/bike.
Start an ad in the for-sale section here.

 

This is the 2nd biggest reason to ride an XJ! I was a member of a group dedicated to Honda Rebels, and those guys would complain that the motorcycle hobby is drying up with the next generation, and in the next breath bad mouth anyone born after them and drive any new blood out of there! They'd mock them for the language used, the clothes it was assumed they were wearing, the style they wanted their bikes to be... Like black paint on an engine? Must be a millenial with pants hanging around your bum. Want to cut down the rear fender? Millenial obsessed with the bobber "fad". It got so bad, that if I hadn't already sold my Honda, I would have sold it!
This place is the best, I sold my XJ before I even bought my Rebel, and years later, I keep coming back!

 

Bobbing a Rebel improves it.

 

They all hated the new Rebel so much, they called it the "not-Rebel". I became persona non grata after mentioning that I'd like to try one on the next test day at the local dealership. Well, that, and a few other comments...

 

I read that forum too my way or the high way

 

^THIS^

This is EXACTLY what I'm talking about.

 

darn people who don't know nuthin about the bikes they are trying to fix. they should know everything already damn young wippers nappers with their hats on side ways. how dare they ask questions. get off your phones and stop texting read a book and quite bothering me.
whew.
your bike is not vintage it is only 25 years old reply but it is, it is Japanese that's the vintage.
no its not! vintage is how old it is not the country of origin.
I wonder why no one wants to join my forums?

 

Pfft.... Everyone knows that real motorcycles are pedal-start and belt-driven.
Multi-cylinder engines are nothing but a passing fad.

 

Manual oil pumps are the only REAL oil pumps. Total loss forever!

 

Internal combustion is infernal combustion! Safety bikes are the work of the devil. Highwheelers for all!

 

Hi! I'm also new on this forum, and instantly found this to be very useful. Haven't been working on carbs earlier, but this spring took 'em off the bike (750 Seca -82), dismantled and washwed with ultrasonic cleaner. While dismanling, I took pics of every step to make sure I put everything back to right place. Reassembled them with repair parts and started adjusting. Couldn't get 'em working properly so I started googling and came up to this forum. Reading this topic I found out the reason. Can you spot it in this picture? Everything has been put back together exactly to same place I took similar parts off - or so I thought 'til seeing the pics in this topic.

BTW, I'm from Finland, greetings from here!

 

I think those jets are in the wrong holes.

 

Exactly! Will go to swap them around tonite, think she'll be working a lot better after that...

 

if you had the air jets out remember the small air jet goes over the large fuel jet

 

The air jets I had correctly. But for some reason I had put the fuel jets in wrong places even though I had the reference photos. Fixed that last nite and now she's working pretty nicely!
Still have to get the valves adjusted and carbs synced, trying to get the YICS tool in my hands... But I can already ride and the bike runs better than the whole last summer!

 

bet your plugs are happy now too.

 

I think so!