What's with these mixture screws? / down the carb hole we go

First post here. Kinda inspired by this thread to make my own: http://xjbikes.com/Forums/viewtopic/t=4 ... art=0.html
Thanks to the wealth of info here I'm still at it with this bike (81 XJ650H) and enjoying the work despite the headaches. Bike's got 24K miles and was sitting in a friends garage from previous roommate who left town, so he sold it to me for $100. Not bad and it ran well at the beginning, but its been having issues/stopped running. Maybe related to running the old gas through?

Inspected brakes (need new brake line but waiting until I get to MC)
Replacing fuse box
new battery and air filter
just got new non-resister plugs and two new plug caps after i realized PO had resister plugs and caps on. old plugs were seriously carbon fouled.

On the carbs now and then I plan to do valve adjustments, sync carbs, etc.

SO, I pulled carbs from bike and did some preliminary cleaning/inspection just to get used to finding my way around them and put images to all the words I've been reading, before diving into the church of clean. When I get to the infamous pilot mix screws they are looking seriously damaged, but I can't find a good photo on the site to reference. Definitely haven't seen any that look like this. Did someone try to drill them out? Or is this normal and I just need to proceed with getting tight fit screwdriver/heat/olive oil, etc? Any advice on how to proceed? It might be hard to tell from the photos but there are some small flat head slots in those oddly shaped holes.

Also including shot of bottom rack with carb 4 (i think? or 1?) bowl removed gasket was busted and there was some major build up of this crystillized sort of gas stuff. Also found some in 3 but none in 1 or 2.

Thanks in advance, and there may be more questions to follow. Hoping to get through the carbs and valves in the next two weeks or so. And did I mention I'm crossing fingers budget on these initial projects won't exceed $500...

PS. Anyone in the Twin Cities/St. Croix River Valley region who knows these bikes and feels like swinging by to help give me a little in person guidance, I will happily offer beer and/or lots of good organic veggies (I work on a farm near Osceola)

 

The image isn't sufficient resolution to zoom in, but they look pretty normal to me. Get a wide flat head screwdriver and, making sure to apply sufficient downward force while keeping the blade of the screwdriver square with the face of the jet, twist them out. Its a bit tricky, but I just went through this same thing breaking apart the gummed up carbs on my XJ700. No worries.

 

Re: What's with these mixture screws? / down the carb hole w

OK thanks. Since I couldn't find a photo of what they're supposed to look like I wasn't sure. Attaching a zoomed in version anyways.

 

Oh wow, that was not the picture I was looking at. My carbs do not have that jet/screw.

 

maybe what i see there is the cap that was drilled to remove it (let's hope)
try to pry that brass thing off with a sheet metal screw and maybe you'll find the mixture screws under them

 

+1 what polock said. Looks like someone drilled holes in the "keep grime out" caps but didn't remove them.

Gary

 

Re: What's with these mixture screws? / down the carb hole w

Looks like they may have gone too deep with the drill.
You should be able to see a straight slotted screw head that lies underneath those brass cap. You do NOT want to booger the slot up!

Like Polock said; try to carefully screw a sheet metal screw into the brass cap and see if you can then pull out the brass cap (using the screw head as a handle).
You may want to file the very sharp tip of the screw off so that the screw can get deep enough in the existing hole and the threads can get a decent purchase on the sidewalks of said hole.

Good luck, keep asking for assistance, you will find it here.

P.S. not to be a negative Nancy, but you will be spending more than $500.
There is still much to do, and it sounds like the PO has neglected regular maintenance.
Check your rear brakes and definitely rebuild your MC and brake lines on the front.
Verify that your valves are in spec.
Check the date codes on tires (you only have two, failure is not an option)

Keep asking questions and you will be rewarded with one sweeeeeet ride!

 

They were drilled, now you have to remove them. Thread a sheet metal or sheet-rock screw into them and pry them out. If the hole is a too big, use a nail, or get a slightly larger drill bit and go really slow--the object would be to get the bit to 'catch' in the brass so you can work it out.

It is likely one of two things happened here:

1. po drilled them but didn't know how to pull them
2. po drilled them, and then put them back in......whether or not he pulled the screws remains to be seen.

I doubt the screwdriver slot it messed up, and I think you'll probably be able to turn them out pretty easily.

Put a couple drops of KROIL or PBBlaster in the well anyway, after you pull the caps. That will lubricate the threads in case some dirt has gotten down in there.....

You'll be fine.

Hank, I bet you do have them, you just never saw them with the cap still there.........

Dave F

 

Re: What's with these mixture screws? / down the carb hole w

sidetrack:

Sally -
Are you at the Philedelphia Community Farm?
My wife and I were out there about 6 years ago - great place.
Do they still have the llamas?

 

Re: What's with these mixture screws? / down the carb hole w

OK, I was thinking something was not quite right there.

So those holes are pretty wide, but i suppose I can try finding a screw with the right diameter to grab and pull out that plug. Should I try to get some lube in there or will the plugs come out easy? I can see the slots underneath, and from what I can tell there's no damage to them.

I know I might go over 500, but trying to be careful $$wise at this point so I'd like to do it as cheaply (but still as safe) as possible. Rear drum was in good shape and friend had replaced front tire so that's pretty much new. I will need a rear tire and to replace brake lines and pads at some point though they have some life left and maybe rebuild/replace MC? and.... yea probably other things I haven't though of yet 8O All that said for someone with pretty much no previous auto mechanic experience this bike seems like a good place to start and I'm enjoying the learning process (mostly).

Not at philadelphia farm but nearby! I've heard great things about that place and the folks I work for are good friends with the folks who started/ran Philadelphia farm. I'd like to visit sometime... in my learning to ride phase when the bike was working I was riding by their farm a lot! Not sure about the llamas though

 

Just stick something in the to pry them out .... They're not pressed in hard, just rather firm. Just go at it---- you're psyching yourself out over it. When you get them out, you're gonna say, " that was it ?!?!?"

 

I knew nothing about turning a wrench. Then way back when I got a xj650 and found this site. With there help and lots of times taking my carbs apart and reading,lots of reading I became good at fixing motor vehicles. By trade I cook for a living and I'm damm good at it. Read reread and ask questions of you haven't read the answers already. Post pics so people can see what you see, it helps. Also when you fix the problem tell us what you did so others like me and new people with similar problems can read what you did.at worst if you break something there are parts available and priced good too. Keep turning that wrench, you will be riding soon and its feels great to say , yeah I fixed it myself.

 

Don't worry about being able to re-use the caps. They're shot. You can use pencil erasers for caps (easier removal later). Before removal of the mix screws flat file a screwdriver to fit the width and length of the screw heads precisely.mark or score it. It will help you more accurately set the screws when the time comes.

Gary

 

If (WHEN) you pull the carbs to thoroughly clean them ...you ARE going to do that, right?...... You'll put everything to factory settings any way, so no need to measure the depth of the head. When you reassemble, you'll run the screws down to a "soft- seat" and the back them out 2.5 turns each. Do a bench sync, and if you wish wet-set the floats. Get your valve clearances in spec.
Then you start the bike and dial it in the rest of the way..... You'll be so close that it won't be much adjustment.

 

Fiddles, some standard screwdrivers do not fit the slot in the head of the screws well enough to get a consistent setting. Filing down a standard flat head for the mix screws acts similar to filing a phillips to act as a jis. Iirc this is one of Rick's suggestions. It doesn't take much filing/grinding. I have one for mix screws only.

Gary

 

I do indeed have them, I just hadn't looked at that area as I was dazzled at how sparklingly zestfully clean the insides of my carbs look (after days of dunking and ultrasonic zapping, of course). Geez, I went through this on my last couple of Harleys, gently drilling out the air screw caps but those bikes were from the '90s, I didn't think that particular "EPA Says Don't Touch This Screw" rules reached all the way back to 1985 motorcycles.

 

"Don't touch this screw" began in the late 70's on some bikes and the early 70's on cars. Honestly it wasn't a bad idea. I figure it's one less thing for an incompetent PO to screw up (hopefully).

 

Re: What's with these mixture screws? / down the carb hole w

Thanks hogfiddles, you were right, they came right out no problem. And I like the pencil eraser plug cap idea. Screws came out easy though they were way outta wack... some 6 turns out, some 3, etc. And yea I'm in the process of getting them "zestfully" clean now.

I know about filing down a flat head for the mix screws, but what's this about filing down a phillips to better fit the JIS screw heads? I'm trying to avoid dropping $30-40 on a few screwdrivers...

 

So the someone WAS messing with them and put the caps back in.....

 

Substituting pencil erasers for caps is not my idea. It's in one of the forum threads. As is filing/grinding phillip screwdrivers to have them fit like jis. Iirc the screws are specifically designed and jis drivers fit them grabbing all of the slots which prevent buggering the heads and makes for easier removal of the stubborn ones . Filing standard screwdrivers a bit will return similar results.

Gary

P.S. - The way I learned it is that solid "bread and butter" techniques are to be shared with family and close friends only because they are $ makers. Xj bikes shares it all.

 

Exactly......we don't keep any secrets here. Well........maybe just a couple-----lol

dave

 

Re: What's with these mixture screws? / down the carb hole w

Nice I like it, No secrets... and with that... a few more questions:

this may be an insignificant detail, but in rick-o-matic's how-to I read the main jet should have 16-24 of those tiny holes, but mine only have 14. Is this OK? Problematic?

Attaching a photo, but my main jet slotted screw (the 110), was stripped out by me, foolishly. Now, I know a new jet assembly from chacal is like $10, but do I really need it if the actual jet is OK? Will this screw affect performance?

Anyone out there with an extra set of stainless/replacement screws. I read on one thread from April that some folks buy in bulk and I'd be interested in purchasing a new set of screws.

And last the big question, to break or not to break? The carbs on the whole don't seem that dirty, but without breaking them I can't really inspect throttle shaft/fuel passageways, etc. right?

 

Re: What's with these mixture screws? / down the carb hole w

As long as the hole in the jet is not damaged or obstructed, then it will perform fine. If you have a fine file, you can always clean up the head a little so it looks nicer.

Break if you have the time and skills. The carbs are 30+ years old and the wear items are way past their service life; even if they are still "usable", they won't be for much longer.........

 

I totally understand the reluctance to break the rack. I used to be that way. Now, I have no fear of doing it. I learned it the hard way-- jumped in and started. Then, I learned that others here already know what they're doing too.

Long story short, YOU CAN DO IT. We're right here beside you at every step. Even if you forget what something is, or where and how it fits, we're here for you to ask. Show a pic, we'll ID any part for you.

Tear it it right down and CLEAN EVERY PART scrupulously. Replace all the seals and rings. If you don't, you'll be doing it soon enough.

You CAN do it!!!!

Dave F