Another Newbie's Carb Concern

Hi everyone, I just wanted to say that, having just purchased my first motorcycle, an 82 XJ550J, I was stoked to find this site! I have been quietly perusing the forums for the past couple of weeks preparing to clean the carbs, and decided to go for it today.

I've been following Rick's excellent How-To on the subject, even though I have Mikunis and his post is for Hitachi's. But I already buttered the tops of two of my four pilot jet screws. I used a screw extractor and got them out okay, and now I need new ones of course. But I'm wondering if, when I put the new ones in, can I use anti-seize on the threads to avoid this in the future? Help appreciated.

 

Okay, another question. Sorry, I'm still reeling from the carb cleaner fumes. I had to remove the air box boots because they were a little too stiff to stuff back into the box. I'm wonder what I can use to clean, protect those. I've heard Armor-all works. Any thoughts?

 

Hey SCribetree, I have your idle mixture screws and parts! You can see all of the items that I carry over at:

http://www.xjbikes.com/Forums/viewtopic ... t=180.html

Oh, and to answer your question: YES, please do use anti-seize on those screw threads. Please!!

And pretty much on every other screw on those carbs, and the entire bike!


ims3) OEM Mikuni Idle Mixture Screw Set is correct for all original XJ550, XJ700-X, XJ750-X, and XJ900 carbs. Very similar to the XJ1100 mixture screws, but the needle tip diameter is much smaller....they may work for XJ1100 models, but I'm just not sure. Each complete set contains one brass slot-headed idle mixture adjustment Screw, the mixture screw Spring, the spring Washer, and the sealing O-Ring.

HCP3745 OEM Mikuni Idle Mixture Screw Set....contains the brass idle mixture screw, spring, spring washer, and the o-ring. Each:
$ 16.00

HCP3745SET4 OEM Mikuni Idle Mixture Screw Set, set of 4:
$ 59.00



NOTE: if you're going to be replacing less than all four idle mixture screws, I would suggest replacing at least the mixture screw o-rings, washers, and springs on the carbs that you are NOT replacing the screws on:


ddd) Aftermarket Mikuni Idle Mixture Screw O-RING.....a "must-replace" item when rebuilding your carbs. Made of long-lasting, fuel-resistant Buna-N material.

HCP895 Aftermarket Mikuni idle mixture screw O-ring, fits all XJ550, XJ700-X, XJ750-X, XJ900, and XJ1100 carbs, each:
$ 1.00

HCP895SET4 Aftermarket Mikuni idle mixture screw O-rings, set of 4:
$ 3.00


eee) Aftermarket Mikuni Idle Mixture Screw o-ring WASHER.....also a "must-replace" item when rebuilding your carbs. Made of long-lasting, fuel- and water-resistant 18-8 stainless steel material.

HCP896 Aftermarket Mikuni idle mixture screw o-ring Washer, fits all XJ550, XJ700-X, XJ750-X, XJ900, and XJ1100 carbs, each:
$ 1.50

HCP896SET4 Aftermarket Mikuni idle mixture screw o-ring Washers, set of 4:
$ 5.00



ims6) Aftermarket carb idle mixture screw TENSION SPRING, brand new reproductions exactly replace damaged, rusted, or missing originals. High-strength carbon-steel coil springs have a baked yellow-zinc plating as original.

HCP6574 Aftermarket reproduction idle mixture screw Tension Spring, fits all Mikunii BS-28, -30, -33, -34, and -35 series carbs as used on all XJ550, XJ650 Turbo, XJ700-X, XJ750-X, XJ900, and XJ1100 models, each:
$ 3.50

HCP6574SET4 Aftermarket reproduction idle mixture screw Tension Spring, fits all Mikunii BS-28, -30, -33, -34, and -35 series carbs as used on all XJ550, XJ650 Turbo, XJ700-X, XJ750-X, XJ900RK, and XJ1100 models, set of 4:
$ 10.95

 

Thankx Chacal. I'm going to be pulling the tops of the carbs off today, so I'm going to wait to see what else I need before ordering, but I'll definitely be in touch. The only thing is, you had mentioned the idle mixture screws with O-rings, and maybe I'm wrong, but I thought the ones I stripped were the pilot jet screws, the ones sunk way down at the bottom of the lower stem next to the main jet. Same thing? Either way, I didn't see any o-ring, springs, or washers. Are they way down in the depths and I just haven't gotten to them?

Also, any word on how I should treat the rubber parts? Boots, diaphrams, etc?

 

ya the idle adjustment screw and the pilot jet are two different things... just make sure chacal knows exactly what you want and he'll hook you up with the goods all my intake boots i've coated with hi-temp Silicone to seal cracks and liven up the rubber a bit... i've heard boiling them helps with flexibility... give it a try and report back what you find! there is a link in my sig that has links to many places that you could find of interest, give it a try when your looking for an article.

 

Hey thanks spacker. I'll try the boiling/silicon trick on the boots when I put them back on. Hopefully sooner rather than later

 

Yes, as spacker pointed out, the idle mixture screws (sometimes called the pilot mixture screws) are completly different animals from the pilot fuel jets---and there are no springs, o-rings, or washers used with the fuel jets, so you can stop searching! Sorry if I sent you on a wild-goose chase......

Oh, and of course, I also have those replacement pilot fuel jets available:

ef) OEM and aftermarket Mikuni brass PILOT FUEL JETS, sizes as follows, fits all XJ550, XJ650 (except Turbo), all XJ700-X and XJ750-X, XJ900RK, and XJ1100 models.

NOTE: stock Mikuni XJ series carbs used the following original pilot fuel jet sizes:

#32.5 XJ650 Turbo LK (1983)
#35 XJ550 all models and XJ700-X all models
#35 XJ650 Turbo LJ (1982)
#37.5 XJ750-X and XJ900RK US & Canada only
#40 XJ900 1983-84 except USA or Canada
#47.5 XJ1100


All the other sizes are for "tuning" or re-jetting purposes when changing intakes or exhaust systems.


HCP5223 OEM Mikuni PILOT FUEL JET #32.5
$ 15.00 each
or
$ 55.00 set of 4

HCP5183 OEM Mikuni PILOT FUEL JET #35
$ 15.00 each
or
$ 55.00 set of 4

HCP6890 OEM Mikuni PILOT FUEL JET #37.5
$ 14.00 each
or
$ 51.00 set of 4

HCP6889 OEM Mikuni PILOT FUEL JET #47.5
$ 16.50 each
or
$ 59.00 set of 4



HCP6949 Aftermarket Mikuni PILOT FUEL JET #30
HCP6950 Aftermarket Mikuni PILOT FUEL JET #32.5
HCP6951 Aftermarket Mikuni PILOT FUEL JET #35
HCP6952 Aftermarket Mikuni PILOT FUEL JET #37.5
HCP6953 Aftermarket Mikuni PILOT FUEL JET #40
HCP6954 Aftermarket Mikuni PILOT FUEL JET #42.5
HCP6955 Aftermarket Mikuni PILOT FUEL JET #45
HCP6956 Aftermarket Mikuni PILOT FUEL JET #47.5
HCP6957 Aftermarket Mikuni PILOT FUEL JET #50
HCP6958 Aftermarket Mikuni PILOT FUEL JET #52.5
HCP6959 Aftermarket Mikuni PILOT FUEL JET #55

All of the above Aftermarket Mikuni Pilot Fuel Jets are priced as follows:
$ 4.50 each
or
$ 14.00 per set of 4

 

Just to let you know I used the wifes hair dryer to heat up the boots to put them back on works great and you don't have to dry them off when you are done.

 

Grease the "Channel" on the Boots to allow you to rotate them easily when you get the "Flaps" on either side of the cut-out on the aiirbox.

There should be alignment Tabs for the Boot and the Airbox.
If not ... rotate the Boot until you get the Maximunm coverage of the Carb Intake.

Anti-seize compound is a good idea on the Pilot Mixture Screws.
Keep it thin and not down the shaft of the Needle.
It don't take much to clog the Inlet Hole.

 

You guys have been a big help. And I'm happy to report that a previous owner had pulled the plugs over the pilot mixture screws, but they came out no problem, with a healthy dose of cleaner/WD-40. I also discovered the o-rings, washers, and springs, and managed to keep them all – so far.

What's strange is that the middle two pilot mixture screws were set 2 turns out, but the outer two were out about 4 turns. When I put them back in, I should bottom them out and then unscrew 2 1/2 or 3 turns? I feel like I've seen you guys talk about both.

By the way Chacal, how do I order from you? With a PM?

 

PM, yodel, use the force..............yes, just send me a list of what you're looking for and I'll reply with all the info that you'll need (and some would say even more!).

 

Hey Scribetree,

Listen to chacal, he has all the parts and info you will ever need.

 

Yes he does and some you don't even know you need yet.

Mikuni carbs on the 550, exploded with pics: http://xjbikes.com/Forums/viewtopic/t=31061.html

VALVE adjustment, you can't properly sync the carbs if the valves aren't in spec: http://xjbikes.com/Forums/viewtopic/t=14827.html and Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

When cleaning and pre-setting up the carbs, a good accurate bench sync is important, as are accurately WET-set float levels.

Set your pilots at 2 3/4 turns out for now; to be fine tuned later. What you found was the result of Yamaha using an EGA to tune a brand new motor.

We'll talk brakes later.

 

Yup, still does, even 4 years after the original post