Carburetor jets

Hey all. I have a 1982 Yamaha xj650 Maxim and I just want to make sure the Jets go back in the correct places after I give them a thorough cleaning. The top hat side has three 205 and 50 jets and one has 80 and 195. When I took them apart a few years ago I think I put them in the correct spots. Could someone clarify the proper carb bodies they go into? Thanks in advance!

 

These are the original jets that came with the bike.

 

Give this a shot.
https://xjcd.org/service-manuals

 

It doesn't mention anything about the air jet sizes.

 

http://xjbikes.wikidot.com/carb-specs

One of the after market service manuals had the pilot jet and main jet locations wrong.
Main jet is always in the middle and Pilot jet and pilot air jet is on the end.
Pilot and main jet go on the bottom where the bowl is.
Pilot air jet and main air jet go on the top where the diaphragm are.

 

I understand that part of it, but I have two that are different from the rest of them and want to make sure they go in the right carb when I put them back together.

 

For your bike, all 4 carbs should use:

a) the same sized main fuel jets #112
b) the same sized pilot fuel jets #43
c) the same sized main air jets #50
d) the same sized pilot air jets #205

 

They should all be the same as Chacal stated above, but to add it looks like you may have jetting in one carb for a 750 Canadian, perhaps that one carb was replaced?? You would need to verify the Main fuel jet and Main needle also as they are different for 650 vs 750.

Years & Models: 1981-3 XJ750 Maxim, Midnight Maxim, and Seca Canadian models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 15T00 (Maxim, Midnight Maxim)
Carb Model ID: 5H200 (Seca)
Main FUEL Jet Size: #120
Pilot FUEL Jet Size: #43
Main AIR Jet Size: #80
Pilot AIR Jet Size: #195
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-14
Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
Idle RPM's: 1,050 rpms

 

To my knowledge, these are the original jets. The guy I bought it off of in the 80's was the only owner and never did any modifications.

 

It would not be normal for carbs in the same rack to have different jets. There is a mystery here.

 

Main fuel jets are 112
Pilot jets are 43
Carb 1,2,4 have 205 and 50
Carb 3 has 195 and 80
I can't see any numbers on the emulation tube.

 

Hitachi emulsion tubes have no numbers on them (unlike Mikuni carbs, which have etched "sizes" on them). Luckily, all HSC32 series carbs on XJ650/750 models use the same tubes.

For some reason, someone has swapped out the carb #3 air jets.....maybe even replaced the entire carb body at some time.....or the factory just dropped in a different set of jets (or entire carb) for some reason. You should check the engraved "size" on near the very top of the main jet NEEDLE shaft....your carbs should be size Y-10

 

I did replace one body after breaking one of the float posts. I kept the old body and found the original jets. 50 and 205. Mystery solved. Thanks for all the help and sorry for the bother.

 

No bother at all, love solving mysteries! BUT..........you probably need to check the main jet NEEDLE "size" in that #3 carb and make sure it matches all of the others.........should be the Y-10 size......earlier XJ650 Canadian models used Y-12 needles, while the XJ750 carbies used the Y-13 or Y-14 sized needles. And you don't want a carb bank to have mis-matched needles, either!

 

When I purchased the body, it came with the two air jets and nothing else. No needle or pilot jets were in the body

 

the "only owner" could have taken the bike to a shop for a carb rebuild.
my 83 XJ had pilot air jets that did not match factory. The carb set likely was pulled from another bike at some point cause the threading on the idle mixture needle screw did not match the threading of an 83.
Just cause you got from an original owner, does not mean a shop did not do some shenanigans that they did not tell the owner or the owner did not know about it.
its possible that a mechanic changed jets to compensate for float levels not being properly wet set and the mechanic did not really know what he/she was doing.

Constant Compression across all 4 cylinders, valve adjustment, carb cleaning passages, consitant jetting, consistant wet levels, idle mix, syncro is the key to carbs IMO. (Did I miss anything?)
Skip one of those that are out of wack that you don't know about and it can cause an issue.
Yes, a lot of work and a lot of time, but it pays dividens. My bike runs GREAT does not need long to warm up. 2nd bike I did ran great when I sold it but took a tad longer to warm up. 2 other carb sets I rebuilt did great after the owners did all the other work mentioned.