Bogged down at low Load/RPMs

[GLoweVA]

Okay, so here's the problem and the solution for all those that may get this problem. (or already have )

So, on the way home from work the bike started up fine, but as soon as I started to go it was bogging down like it was missing on one or two cylinders.
Once i got to about 3-4K rpms and about 20-30mph she smoothed out and ran fine while I had some throttle, but as I eased off the throttle it started bogging down again.

So, I got her home and parked it. I got to thinking that it happened at low rpms and low load on the bike, but when I rev'd it up and started pulling harder it smoothed out.
I figured maybe it was the pick up coil wires (thus at load there would be no vac advance like at idle)
The other thing it could have been was a clogged pilot circuit so that when I got into the mains, she pulled okay, but not so good at low throttle position.

So tonight I checked the ohms on the pick up coils while moving it and no change. I sprayed the headers and found out it was #2 that was the issue, so I also checked spark and compression on #2, OKAY, Humm....
So it must be fuel related...
I pull the tank off and look down at #2 idle mix screw and guess what:



IT'S NOT THERE!!!!

Damn, it must have backed itself out. Oh well, I'll pull one from the G's carbs.

Wait, what do I see sitting under the carb bank......



How can that be??? It sat there for 2 days and at least 60miles?

I pulled the spring and washer out of the G's carbs and put a new o-ring on it and just a small dab of red locktite and put it in. A quick check of the sync and put the bike back together and a test ride.

YAHOO!!!
All is right in the world again.

[MPittma100]

Good Find

Don't think I've seen that before. Good/lucky find there. Not so sure about the red Locktite though. It may be permanently adjusted now. Hope it works out.

MP

[Rasputin]

Don't think I've seen that before. Good/lucky find there. Not so sure about the red Locktite though. It may be permanently adjusted now. Hope it works out.

MP

Yeah same thought I had when I read RED.

[motoman]

+2!.............Oopps.......hope that cyl. likes its PERMENENT mixture setting. Only saving grace would be if some gas vaper weeping past the O-ring kept that red loctite from setting up. BTW, IMO the blue loc-tite would work good on the sync screws. I say that because on my Honda ST sync screws, the factory has put a tan/brown similar product on the sync screws to keep them set whereever the adjustment ends up. Originally, I had them synced by a certified Honda tech as I was not that familiar with the procedure on the four downdraft Kiehns. Procedure setting up to do the sync is a bit more involved than our trusty ole' XS's. What the factory has done has kept those in sync for 8+yrs. now. Likely the blue loctite would do the same for our XS's, and a plus would be any slack in the mating threads would be eliminated since just a tad pressure or an ever so slight tweak on those screws change things drasicly........JAT folks.

[GLoweVA]

The red was the only thing that I had available and I used a VERY LITTLE dab of it. It was barely enought to cover about 3 threads worth only about 1/2 way around.

I just didn't want that sucker to back out again. Especially since I'm riding her to XS SE this year.
I can see why there used to be 'tamper' seals in there, besides preventing us from tinkering with the mix, it kept the parts in there also.

On a side note, these pics were taken with my phone and I found a neat feature to get the flash to work to illuminate down into that hole.
At first glance I couldn't really see down in there with it being right under the frame and coils and such, so I took the pic, then looked at the screen on the phone and saw the detail! WOW!

The point of this thread was to detail the symptoms and the fix so that others may not have to chase their tails. I wish I would have looked at the carbs before I did any electrical checks, that would have saved me at least an hour.
I guess the moral of the story is: Look for anything outta place and trust the obvious.

[Rasputin]

Look for anything outta place and trust the obvious.

Thought that was what we were doing commenting on using red loctite. Far as I recall must be heated to 550 degrees to loosen it, 3 threads or 90 makes no difference. Good luck with that. I know I won't be trying it any time soon.

[3Phase]

If you can get the mixture screw out without slagging or tearing up the carburetor body that low-strength purple Loctite 222 would be perfect for mixture screws, even the ones that are missing a few threads here and there.

[ViperRon]

A cheaper easier fix for the screw comming out is something I have used for years with no issues in situations like this is super glue jell. What you do is put a very small amount on just a spot and let it almost completly dry before putting the screw in. Since the drying process started it will not get a good solid grip but will be sticky enough to hold. Super glue is not developed to have as good a hold and does break loose with accetone or nail polish remover. Now if you coat the threads heavy and put it in wet you will be just as permanant as the locktite. Lucky that you did not loose the screw and it is a symptom people here will deal with expecially the more you turn those screws. The other issue is if you have those screws turned out a long distance like more than 2 turns due to being too lean the springs do not provide as much hold on them.