4 Carbon-fouled Spark Plugs

Almost finished completing my first tune up w/ my new (to me) 1985 XJ700 Maxim. Pulled the plugs and all four were equally carbon-fouled (black sooty residue - posted below). The plugs looked fairly new (probably put in reciently - prior to the sale of the bike). I'm assuming it is the air filter (first guess). I replaced it w/ a K&N as the old one was in worse than terrible shape (posted below).

When I put the 4 new plugs in, the bike fired right up. Let it idle for about 5 minutes and shut it off (its raining so I really didn't want to go anywhere). Pulled the plugs this morning and they look fine. A neighbor of mine who is a Euro car mechanic, recommended that I check them after a week and agreed that the air filter might be the culpret.

First question, am I on the right track?

Second question - start up procedure? The temps here in the Pacific NW are still in the low 40's in the morning (Sunday will be in the lows 30's). I set the fuel selector to "prime" and turn the choke "on". Let it idle and slowly reduce the choke. I've been letting it "warm up" for about five minutes before riding it. Before I pulled the plugs and replaced the air filter (yesterday) I felt the bike would "hesitate" at lower speeds usually during the first ten minutes of riding - I'm assuming this happened because it was...

a - too cold outside
b - I didn't let it warm up enough
c - the air filter was clogged like a snot-nosed 2nd grader
d - the plugs were fouled
e - all of the above

I've only taken it out for 3 short 25 mile spins so I have no long-term experience on this machine to compare it to. For reference, the bike has 14,000 miles on it and had some carb work completed at a local independent dealer last fall.

 

Sam in Vancouver, Washington here.

In answer to your question - yep I think you're on the right track. It's good that you've changed the sparky's and got a new air filter.

I have a Kawasaki 550 and Honda Silverwing 500, and the start up is the same, and I checked the XJ CD's I got from THIS WEBSITE - which covers ALL the models - the start up is the same in the owners manaul.

Again - I live in Vancouver, Washington State. Low's here overnight are in the high 40's with the daily temp range in the 50's. We've only had a couple of days near 70. Problem isn't so much the Temp - it's the amount of moisture in the air. I'm assuming that Spotucky is a big city on the eastern middle side edge of Washington State.

Also - you shouldn't have to PRIME to start. This is only used when you have serviced the carbs or run out of gas. Put the petcock to ON and leave it there. The petcock is vacuum assisted and does just fine to get the go juice to the carb bowls. Prime just by passes the diaphram in the petcock and fills the bowls. Again - you shouldn't have the petcock on PRIME - put it to ON.

Start up proceedure.

Make sure the bike is in NEUTRAL.
Put the choke on FULL
Kill switch to RUN
Key in ignition - turn to Start.
NO THROTTLE.
Hold start button, engine turns over.
DO NOT HOLD START SWITCH DOWN FOR MORE THAN 10 SECONDS.
Engine should start and run. After a short bit it should rev up.
Per the owners manual - if the outside temp is above 50 degrees F let it warm up for about 25 seconds, then push the CHOKE in.
If the temp is below 50 degrees F, leave the CHOKE on FULL for 40 seconds, then push to HALF WAY for another 2 and a half minutes.

On my bikes - after I get the bike started, I adjust the choke to hold idle at 2000 RPM's for a couple of minutes, then I let off the choke to about half. If you let off the choke, and then crack the throttle and the engine stumbles, then it's not warm yet. Put the choke on half and let it idle a bit longer. The engine should not stumble when throttled up, off choke, and fully warmed up. If it does stumble, you've got a carb mixture problem.

Clear as mud? Really, the problem around here (read Pacific NW) isn't the outdoor temp - the engine is air cooled and when fully warmed will like a little cool air around it at idle. The problem is the amount of moisture in the air and the formula of gas we get. But that's a chemistry lesson - and you don't care - all you want is your bike to run - Right?

Hope this helps. And HI brother Washingtonian - Welcome to the site!

Hey - Is your name SAM too? 2 Sam's in Washington - who' da thunk it?

 

Thanks for the help. I appreciate it. I also ordered the latest "general motorcycle repair guide" from Amazon, it just hasn't arrived yet. Right now I'm struggling with the brakes. Just installed some new pads and have a bit too much contact with the rotors. The old pads were thrashed.

 

Here's a link with some info you might be able to use.
http://www.dansmc.com/mc_repaircourse.htm

 

Believe it or not, but I did a quick search online (once I pulled the plugs) and Dan's site was the one that I went to. Very helpful as I was able to pinpoint an exact match.