Ok! a question i should know the answer to.

[XS1100 Newbie]

The other day, before a 570 mile run on the weekend, i ran my valves, synched, adjusted carbs, re-checked synch. I thought everything felt fine. On my trip i noticed that i was having to downshift to 4th a lot more than normal. I figured it was all my weight from the camping gear. Ended up i was wrong. I found out when kicking the speed up a ways, it felt like i was running out of fuel at 80 MPH. Kept trying, but with no luck. One of my riding buddies said he thought it smelled like it was running rich, as he was riding behind me. Other than that, the bike was great. It bothers me that it would run 110MPH before adjusting, and then only 80MPH. I guess i will try to readjust the carbs, and here lies the question i should know, which way does the air fuel screw turn to lean it out? Could it be just a bad synch?

[BA80]

Those mixture screws will have very little to nothing to do with the engine running at highway speeds.

It sounds like you may have something going on that's completely unrelated to the adjustments you made. The rich exhaust is probably due to a misfire. How old are the plugs? Check all ignition components.

[mack]

Mixture screws

I agree, at that speed your on your mains, if loaded up the advances is working as well. What RPM about 5.5-6K?

[Bigfoot]

I could be way off, but is it possible that you partially kinked your fuel lines?

[IanDMacDonald]

I guess we need more info regarding symptoms. You say it's like you're running out of gas, which gives me a visual of a chugging and two cylinders running. However, that is totally different than a possible "wall" you're hitting, which is reminescent of blocked air passages on the intake bell housing of the carbs using Emgo pod filters. So, if you're running well on all four cylinders up till 80 mph, that eliminates a lot of issues except an air/fuel issue with carbs. I'd suggest a re-sync/tune, and to check for an obstruction on intake side.

[motoman]

The other day, before a 570 mile run on the weekend, i ran my valves, synched, adjusted carbs, re-checked synch. I thought everything felt fine. On my trip i noticed that i was having to downshift to 4th a lot more than normal. I figured it was all my weight from the camping gear. Ended up i was wrong. I found out when kicking the speed up a ways, it felt like i was running out of fuel at 80 MPH. Kept trying, but with no luck. One of my riding buddies said he thought it smelled like it was running rich, as he was riding behind me. Other than that, the bike was great. It bothers me that it would run 110MPH before adjusting, and then only 80MPH. I guess i will try to readjust the carbs, and here lies the question i should know, which way does the air fuel screw turn to lean it out? Could it be just a bad synch?

answer to your first question: If mixture screw is on manifold intake side, fuel adjustment. If mixture screw is on air intake side of carb, air adjustment. This is the case with all sidedraft, downdraft carbs, whether they be on a scoot or your weed-wacker. Likely went the wrong way with screw, and not listening for any change in sound. Really need to set each those mix screws at JUST the highest in. vacuum and re-sync. Changing fuel mixture changes vacuum draw, which will have sync totally out of whack until re-synced. Answer to last question: highly likely.

[IanDMacDonald]

Bouncing off Motoman's post, and answering your question, turn right to lean it out, left to fatten it up (rich). Opposite if on other side of carb.

[XS1100 Newbie]

Thanks guys. I am going to go through all points tomorrow, and see what i find.

[XS1100 Newbie]

Today i run the valves again, replaced my coils with vfr1000 coils, did a compression check, (130lbs on all 4 with throttle wide open and engine cold) synched carbs again, re-adjusted carbs, and re-synched. The bike runs a little better, but still the same problems. What i did notice was #4 exhaust cam lobe looked like somebody had been beating it with something. Might need a cam.