Major carb problem!

[jacuff1]

I really hope someone here can help me.
"eXJunk" came with a set of Keihin carbs that wouldn't begin to fit on the motor, so when I found my parts bike that still had the original carbs, I figured I was in business. Not! I started tearing the carbs down to clean them, and had no real trouble until I started removing the pilot screws. Three came out, but the one in the #1 carb didn't want to move. I could turn it a little each way, but it wouldn't move more than a quarter turn. I left it overnight with some penetrating oil, hoping it would free up. Went back the next evening and tried again. I took the screwdriver and dressed the end to be sure it fit tightly into the screw. I kept working it back and forth and managed to get it mostly out until the screw head stripped. I finally carefully drilled a small hole down the center of the screw and used an easy-out to finally get the screw out. When I looked at the screw, my worst fears were confirmed. I saw aluminum was in the threads in a couple of places. I don't know how, but apparently someone managed to cross-thread the screw. I'm hoping I can run a tap down thru and clean up the thread and save the carb body, but I haven't been able to find out what size thread these screws are. Does anyone know? Any other ideas for saving this carb? What really upsets me is that I just passed up a set of carbs on eBay, because I didn't thnk I needed them after getting the parts bike.
Any ideas or suggestions would be much appreciated!
thanks!
John

[nashville_bill]

I had to drill my pilot jets out and had the same question. I thought they were 4.5 mm X .75mm and bought taps online but they turned out to be 5mm X 0.8mm . Good luck with the threads. I thought I had ruined mine but they turned out to be OK.

[newmaac]

I think that Bill is right. You should be able to run a thread chaser and clean-up the threads. You might want to be really careful to consider where the small shavings are ending-up though.
Use some oil to help trap as much as you can. And vacuum as well as possible.
If all else fails, I have a bank of carbs that I have been canibalizing. How the $&^* do you spell canibalizing?? LOL

If it is the same carb body, I will send you one for the cost of the packaging and shipping.
What year/model are you working on??
Good luck

[jacuff1]

It's an 82 XJ1100. I am going to check into getting a bottoming tap at the Fastenal store tomorrow. But if you have a spare body that will work, that might be the best thing. I'm really concerned about ruining this one. I did find another set of XJ carbs, but that's $75 plus shipping. And I have other parts that I need for this bike that I could use that money for.
John

[jacuff1]

Well, I got the 5 x .80 tap, but as it turns out, that's apparently not correct for the XJ carbs. The tap was too small in diameter, and the thread was too coarse. I took the screw into work and consulted with my buddy in the toolroom. We figured out that the correct size was actually 6 x .50. Next was the task of finding a source for this odd size. Fastenal did not have this one. All they had in 6mm was 1.0 pitch, which is way too coarse. I finally found the correct size at J&L Industrial (www.jlindustrial.com), and I have one on order. It's not a bottoming tap, but with a bit of effort, I can make it work. Next up is getting a new pilot screw ordered from the local Yamaha dealer. I just hope it's still available. Cross your fingers for me!
John

[nashville_bill]

You can find just about any tap you want at www.e-taps.com/ofertapage%20001.htm . The part number looks like "G060X050N3" and they have them in stock.
The XJ carbs must have different jets - huh?

[jacuff1]

update

Well, there's good news and bad news. The good news is that I got the tap today, and I was successful in cleaning up the threads in the carb body. Ran one of the other screws down into the carb, and it fits perfectly now. The bad news is that I went to the dealer to order a new pilot screw, and after much looking at the carb parts diagram (three of us!), we could not find the pilot screw listed or in the diagram. So does anyone happen to have a spare pilot screw for an XJ laying around they could spare (XS won't work)? Or if anybody should happen to know the part number so that I can order one, that would work too.
Thanks!
John

[Ken Talbot]

I just checked the thread size on a needle from one of my spare carb banks and it is 6mm x .5 AFAIK, there were two styles of needle: the early pointy ones that had a tendency to break off, and the later ones with a blunt point. My guess is that a needle as listed on the fiche for an '81 H will work for you. You can get the part number here

Better yet, John, send me your snail mail address in a PM and I'll send you one of my spares so you can try it out and verify it for all of us.

[jacuff1]

Sure, I'd be willing to be the "test subject"! My screws do have a "needle" shape, but they are flat (blunt) on the tip where it sticks thru the hole in the carb throat.
Thanks for the offer Ken. I sent you a PM.
I looked at the diagram shown on the page at that link. It's a shame the XJ one doesn't show that. My dealer said that maybe the pilot screws were plugged off from the factory for emission purposes, and might not have been available seperately.
John

[jacuff1]

Good news!

Well, I can confirm that the late XS pilot screws will work in the XJ carbs. The one from Ken came in the mail today, and since I had already assembled and re-installed the carbs (major PITA!), all I had to do was install the screw. I turned on the fuel from my temporary fuel tank and fired her up. Oh yeah, baby!!! It was so good to hear this thing finally run. It does seem to have a slight roughness up until 5k RPM, but it does idle fairly smoothly, revs freely, and all the pipes are putting off heat, so I figure there might still be some gunk in the slow speed passages in the carbs, or maybe I just need to tweak some more on the pilot screws. The longer I let it run, the better it seems to get, so when I finally get a good tank back on it, I will get a bottle of Techron and run it thru the fuel system and see if it helps. If not, I guess I will be pulling the carbs again. I'm hoping this weekend to take it for a short test ride (my temp. tank only holds a quart) to see if the tranny is okay. Hopefully I won't have any of the trans problems mentioned on this site. If so, guess what I'll be doing this winter? Glad I got a parts machine!
Anyway, a big thanks to Ken, and everyone else who has helped me get eXJunk to this point!


John

[skids]

If you just sent the rack-o-carbs to the dealer, you probably should do a couple more things, if you haven't done it since. The first thing is that you might need to adjust the throttle linkages for the individual carbs (synchronize the vacuum pressures at idle speed). After that, you may want to check the pilot screw adjustments (fuel feed screws on the top. That is what you fixed, no?). You can do the last thing with the help of a colortune tool or just examine the coloring of the spark plugs. You seem to be getting "intimate" with the carbs by now and already know about this stuff. =:-)

[schpiff]

Congrats! Sounds like your almost there!! A little bit of synching and tweaking and your on your way!

[jacuff1]

Update!

Well, I finally got a chance to take the bike for a ride today. Even tho it was a short (half-mile) ride, it still felt great to be back in the saddle! I hadn't been for a ride since I sold my Virago early this year. The bike ran great, and all the gears worked as they should, tho the trans was pretty "clunky" shifting and going into gear. It didn't slip tho, so I figure it just needs a bit of adjusting to the clutch, and I should be okay. So I guess we can write an end to this story. Again, much thanks for everyone's help and encouragement!

John