RPMs are up?

OK I changed the donuts and valve gasket on my bike. Everything seemed fine. On Sunday I switched out the handlebars from the ones the PO had on there to stock bars with new grips and a new throttle from Len. Everything seemed OK. I Monday the bike dies on me on the way home started popping real bad, not back firing but a pop, pop, pop. Then it died and would not start. I got her home. She had cooled down and she fired up. It acted like she did when I had some really bad fuel. So I drained the tank. Put fresh gas in and half a bottle of dry gas. Let her sit and she fired up no problems, still making a small popping sound. Rode her on the highway at highway speeds 55-75 MPH ran pretty good all in all. Checked the plugs and the rings around the ignitor part are black, which means a lean condition correct? I noticed today that I am running about 5K more RPMs than normal. Usually my bike in 5th gear runs just about MPH to RPMs equal so if the speedo says 55 (70MPH) I am turning 5500 RPMs now I am turning about 6K.

I am checking the valve clearances Friday, I just don't have a place to work in the dark on the bike and I don't think I am going to have enough day light to do it after work.

I know that is my first step, checking the clearances and getting the valves back in to spec. Is there anything else I should be looking at?

 

Just trying to clarify I got this right: So the popping is gone, and it seems to be running fine now, but now it seems to be running 500rpm higher at 70mph than it was before? And when your speedo reads 55 you are really doing 70?
If you are positive you are running higher rpm at a given speed, it might indicate clutch slippage. Can't think of anything else assuming the speedo and tach are working correctly and nothing in the gearing or tires has changed.

I think my 82 XJ650 runs about 6000rpm at 70mph, and my speedo is fairly accurate as judged against my Garmin.

 

No the popping is still there but less so. It and it isn't all the time, maybe a misfire? I don't know... Yep, I am sure about the RPMs. I used to run 55 MPH according to the speedo and 5500 RPM now it is running 55 MPH according to my speedo. Now, I know 55 MPH is 70 because a few months ago a nice police officer was nice enough to pull me over and let me know, he even gave me a nice citation to go with his kind words...

 

Until one of the great XJ mechanical geniuses shows up and speaks, I'd say maybe you can start by making sure your battery is fully charged and have it load tested. Also, is your fusebox updated? How old are your plugs? Come to think of it, you had the valve cover off, so that means you pulled the plug wires, so maybe you can check those, too.

 

Yes fuse box is updated to blades. I'll check the voltage on the battery. The plugs most likely could use changing, they came with the bike... Who knows how old they are honestly.

 

Just so you know, battery voltage alone isn't a good indicator of battery condition. It may crank well, and even look ok on the meter, but you gotta know if it can handle the LOAD, too.
From another forum:

http://www.jetav8r.com/Vision/IgnitionFAQ.html#a3p3

BATTERY

A subtle problem with motorcycles is it doesn't take much power to "crank" one. So, that's not always a good measure of the battery status. In fact, by the time your battery gets to sounding "low" on the starter its just about gone. AND if it "low" while running it could cause these symptoms: tach jump / tach dropout / random misfire both cylinders.

 

HMMM, I hunt around on how to test with a load if you can. Could be the battery I guess, but she is running rich, black on the plugs.

 

Most auto parts stores can hook your battery up to a machine in the store, and they will load test it for free.

 

Boy talk about trying to string together a bunch of completely unrelated issues into one problem. Divide and conquer:

-You already know you need to get the valves in spec, THEN you can get the carbs squared away and probably get rid of the "popping."

-By all means fully charge the battery and have it load tested.

-Change the plugs. Check the plug caps; be sure the resistor inserts inside aren't loose. Unscrew the caps from the wires; lop about 1/4" or so off each plug wire and screw the caps back on so they get a fresh 'bite.'

-The speedometer issue is most likely the instrument itself. You have (I believe) and electric tach, so I would suspect a "sluggish" mechanical speedometer to be the culprit there.