56.25 mpg on the highway with a windscreen and doing 65+ mph

Am I running way too lean? I have all the stock jets in the carbs and the plugs all have a tan colored edge about 1/4 way around the white part. Valves in spec, carbs synced, and sounds like a sewing machine while idling at 1100 or so rpm. Am I gonna hurt it? I've had it this way for 5 years but only recently started going on the highway with it doing 5000 rpm and up for 20-30 miles at a time.

 

Stock air filter and exhaust?

If it's stock, and you aren't riding at extreme altitudes, you shouldn't have to worry about rejetting. Higher rpm under load does actually "clean" the insulator off.

If you see speckles in the insulator, you'd be looking at detonation, but nothing that you've mentioned sounds bad to me. If don't notice any issues running at 5500 rpm, and it's tuned right...the bike is happy (Mine always asks for more).

You can always post pictures of the plugs and get a reading...

 

That sounds right on par with the mileage I was getting outta my '83 650 once it was running right

 

It's all stock.

 

Long as you got some color on the plugs, it's uniform, and no blistering insulators, it sounds like it's very happy.

 

Sounds happy to me. Keeping it under 75 or so is why the great fuel economy.

Yamaha considered 5000 rpms "cruising" speed for the XJs, according to the EGA manual.

 

Posting pics from my camera is a pita. They look pretty much like this. Some with a little less coloring than in the pic.
http://www.moparmusclemagazine.com/tech ... to_07.html

I have a new set of plugs I'd put in but some of the tips are stuck in the wire ends and I cant get them out but the bike seems to run ok as it is. The new plugs have tips on them that don't seem to unscrew. Any ideas how to get the old tips out of the plugwire ends without damaging them?

 

Your plugs are fine if they look like that but I think you may misunderstand the construction of the plug caps.

As for reading plugs, you actually read the "flame ring" which is the raised portion of the plug just beyond the actual threads; plus the ground strap (which is often incorrectly called the electrode) the thing that you bend to set the gap.

The color of the flame ring and ground strap (BELOW the "bend") give you a true reading; the insulator color may vary widely with today's gas.

Back to the caps:

The correct NGK plugs for your bike should have removable "tips." The top should be a naked thread that the cap grips onto.

INSIDE the plug cap there is a resistor core that screws into the cap.

The plug cap itself screws into/onto the wire; there is a threaded spike inside the cap that screws into the center of the wire.

Unscrew the "problem" plug caps from the wires, and slide the big rubber boots off the spark plug side. LOOK INSIDE the cap, and carefully unscrew the resistor core. You should then be able to extract any "stuck tips" if that's the situation.

 

I think I have the original plug wires as the elbow is plastic. Do those come apart differently? All but one plug has the screw on tip stuck in the plug wire.