Installed 3 ohm coils, STILL missing in the Philippines!!!

[jetmechmarty]

My bike behaved as yours does after I tried to fix it. I had a broken float post. I used a carburetor body from a XS650 to fix it. The 1980 XS1100 and 1980 XS650 run the same carburetor, or so I thought. They aren't exactly the same. With that body in the bank, that cylinder dropped out after a rise in RPM.

Something is wrong with your carburetor. A passage is plugged, or something. Take it out and go through it again.

[BA80]

No one has even MENTIONED checking the pickup coil wires!

[BA80]

Never mind, just went back and saw you have new PU wires. Might be worth checking again though.

[jetmechmarty]

Correct me if I'm wrong, but wouldn't bad signal from the pick-up coil drop two cylinders?

[hanger10]

Jets

I got rebuild kits from the US for the carbs, because one of the original jets was about welded in place. He had to drill it out very carefully with a dremel, and took forever!!! I got the full kit, and turned they werent right! We used the new floats, and thats about it, except for the jet he drilled out, and we had to use the replacement one for that, and its not exactly the same. Also, that is the cylinder that is missing! That cylinder runs slightly richer than the rest, we know because of the coloring of the pipes. But, that was two years ago, and it ran fine up to this point! And, as I said, he has that cylinder leaned out as much as he can.

[BA80]

Yeah, your right. I just listened to the engine missing in the video also.

Hanger 10, did you rebuild those carbs? And, if so did you use aftermarket kits that came with new jets and all? In particular the pilot jets.

Some aftermarket kits come with pilot jets that have too many air bleed holes in them ie; stock pilots have 6 and the aftermarkets have 8.

This can cause a problem very much like what you describe and that can be heard on your vid.

Stumbling on light accelleration. A PITA in traffic.

[jetmechmarty]

Is it possible that that carb picked up a bit of trash? I say pull it.

Marty (DFW)

[hanger10]

Miss

Sorry all, I sorta misstated myself a little earlier. When I was describing the miss, I said rpm and speed didnt really matter, its just whether there is a load on the engine, I meant "light" load, just using light throttle.

[DGXSER]

So the more throttle you give it, the better it runs. Thinking this through, opening the throttle simply opens the butterfly throttle plates. This lets the engine draw more air through the carbs, which increases the venturi effect drawing more fuel, AND starts to lift the slides, opening up the main jets.

Electrically, the more throttle you give it, the more vacuum is created and the timing plate moves further. More throttle = more fuel, which can change the spark required to ignite it.

So, it all seems to come back to either bad pick up wires, bad spark plugs, or a partly blocked or problematic idle circuit. I think if it were me, I'd see if there is another bike like yours around and beg to borrow a set of carbs known to be good to see how that works for you.

Just my thoughts.

[natemoen]

I got rebuild kits from the US for the carbs, because one of the original jets was about welded in place. He had to drill it out very carefully with a dremel, and took forever!!! I got the full kit, and turned they werent right! We used the new floats, and thats about it, except for the jet he drilled out, and we had to use the replacement one for that, and its not exactly the same. Also, that is the cylinder that is missing! That cylinder runs slightly richer than the rest, we know because of the coloring of the pipes. But, that was two years ago, and it ran fine up to this point! And, as I said, he has that cylinder leaned out as much as he can.

So you drilled out one jet. Replaced it with a jet that was not the same as the others and that is the cylinder that is acting up? There is your problem. Get the right jet!

[cywelchjr]

So you drilled out one jet. Replaced it with a jet that was not the same as the others and that is the cylinder that is acting up? There is your problem. Get the right jet!

Yep, I would order kits from georgefix on ebay with the right jets and make sure everything is right in them including the jets. If you have one carb acting up, and it's the one with a different jet, change that to be a matching jet and I'm guessing the problem will go away.

[hanger10]

Jets

But, the carbs were rebuilt 2 yrs ago, and have been fine up until now!!!! And, Im in the Philippines, and I dont even know if there is another 80 SG here, so trying another set of carbs is out!!!!! Hey, thanks all you guys for all the input!!! Im gonna try and stick with it till we get it right!!!

[natemoen]

Ok, what is different about that jet in comparison with the others?

Could be that the problem has always been there it has.just been exaserbated due to other factors as well.

[crazy steve]

If you know which cylinder is missing, start swapping carb/ignition parts (one at a time) with one of the 'good' cylinders. When the problem moves to the other cylinder, you've found it....

[cywelchjr]

I'd start with that nasty looking diaphragm and slide assy. I don't see how that thing could NOT be leaking, but that's just me. But Steve's got it right, swap things one at a time, I'd start with the jet that's different first, and see if that moves the problem, cause if it does, you have found your issue.

I mean think about it, you have 4 of something, 3 are working right, one is not. Ignition is in pair, so that makes ignition far less likely, so carburation is most likely as being the most likely to affect a single cyliner (that or a spark plug). So I'd swap that jet to the carb next to it and see if the problem moves to that cylinder, if it does, you are done troubleshooting, and you just need to order parts (you would just need correct jets).