#4 plug fouls

[HawkChief]

Can someone please explain what could cause 1 plug to continually foul on my 80G? The stock coils had high resistance, so replaced them with accel coils and wires. New plugs and it ran great, but #4 fouled about 30 miles later. Pulled the carbs and all floats are the same and set to specs. Sync'd the carbs. Pickup wires are like new. Rode it for about an hour today, then it started running rough on the way home. Pulled the plugs when I got back and 1-3 look good, but plug 4 is covered with dry black soot. So much gas blew back through the K & N indy filter on the ride home that half the filter oil on #4 air filter was washed away. Can't decide if this is an ignition problem or not. Wouldn't both 1 and 4 have problems if that was the case? Replacing the fouled plug makes it run great for another 30 miles. Any help with this would be greatly appreciated.

[randy]

Sounds to me like the #4 float needle is not sealing.

HTH

Randy

[steelcat]

Have you checked the valve clearance? Did this problem start after the new coils or was there some fouling before the new coils & wires? The new wire to #4 maybe bad, swap #1 & #4 wires & see if the problem "jumps" to #1.

[randy]

The gas shooting back out of the carb is a sure sign of flooding.

Randy

[skids]

Re: #4 plug fouls

If it is indeed flooding due to a bad needle seat (valve), I would suspect that the carb would overflow if the petcock was on prime with the engine off. Otherwise, you might have a problem with the venting in the body above the float bowl (I believe those holes are tiny), or, you need to screw in the pilot screw a bit and re-color that plug. If exhaust gases are coming backwards through the carbs, it could be caused by afterfire (some call it backfire) from an overly rich mixture...or, from crappy exhaust systems. I'll bet you knew I was going to say that! :-)

Originally posted by HawkChief
Can someone please explain what could cause 1 plug to continually foul on my 80G? The stock coils had high resistance, so replaced them with accel coils and wires. New plugs and it ran great, but #4 fouled about 30 miles later. Pulled the carbs and all floats are the same and set to specs. Sync'd the carbs. Pickup wires are like new. Rode it for about an hour today, then it started running rough on the way home. Pulled the plugs when I got back and 1-3 look good, but plug 4 is covered with dry black soot. So much gas blew back through the K & N indy filter on the ride home that half the filter oil on #4 air filter was washed away. Can't decide if this is an ignition problem or not. Wouldn't both 1 and 4 have problems if that was the case? Replacing the fouled plug makes it run great for another 30 miles. Any help with this would be greatly appreciated.

[HawkChief]

I had some fouling before I changed the coils, so I'm pretty sure the coils are wires are not the problem. Pulled the carbs after this post and had a tough time getting the idle mixture screw out of the #4 carb. Lots of gunk in the spring and washer after I finally got it out. If this was blocked would it be enough to cause the problem? I was in some stop and go traffic yesterday right before the problem got really bad. Cleaning the carbs now. Never had a problem with gas overflow, but never had them in prime for very long. Thanks for the quick responses.

[John]

Did you happen to check the tip of the idle mixture/ pilot screw to see if it broken off? That happens quite often. That won't cause a ric condition, but it is something to look for. Maybe it was broken in the past, and the PO overcompensated with jet needle settings?
By the way, I sent you a couple of PMs.

[HawkChief]

Needle tips are all intact. Going to take a close look at the float needle and seat when I get going this a.m. I took two weeks leave (Navy) and have sworn to have this thing running perfectly before I go back to work.

Mike

[John]

I see that your bike is an 80. When you are checking out the needle and seat, check the O ring that seals the seat assembly to the carb body. Be careful when you pull the seat, it may be stuck, and get distorted by the pliers that you use. Go to the GSE shop and see if somebody there would be willing to help. Then go to the hydraulics shop for the new O ring. I don't mind paying for it. Try putting the blunt end of a drill bit in the bore of the seat (snug fit) to prevent the distortion. When you reassemble the pilot (mixture) screws be VERY careful not to snug them down to tight, befroe backing them out. that's what causes the tips to break off. They can be removed, but it is a pain. DAMHIKIJD

[HawkChief]

Found a small spot on the #4 float that has chafed against the side of the float bowl. Guessing that the float is sticking on that spot and flooding the bowl. Sanded the spot smooth on the float and will try to use it until I can get a replacement.

Thanks for the help.

[randy]

Flooding? Now, why didn't I think of that?

Glad you sorted it out. Man, I love this forum.

Randy

[rneal55555]

Hawk,

We should start our own little XS11 Goat Locker section.

[Ken Talbot]

Hawkchief, you might want to try just bending the float assembly a bit to get it to clear the side of the bowl. Try to bend it so the offending lobe moves sideways a bit rather than up or down which would change the fuel level in the bowl.

[John]

Originally posted by rneal55555
Hawk,

We should start our own little XS11 Goat Locker section.

Can I join too? I was in the same sailing club that you guys are. Hell, I probably quit the club before you guys joined.

[xExcessive 1120]

Carburetor Party

Hey all! Been kinda locked up with the old arthritis, but want to thank everyone who posted help on my reamed out idle air screw seat on #3 carb. Now I saw a post on Yamaha carb cleaner ACC-CARBC-LE-NR, and was under impression it could be mixed with water at a variety of strengths. What I got from the dealer has all the letters except after LE-QT I get QT instead of NR. Now I do have quart bottles whose contents contains 2-Butoxyethanol and Xylene. And the instructions call for mixing 3 to 1 with gasoline and feeding the mixture into the float bowls via the two fuel lines ('78-'79 carbs). Now do I have the correct solvent or does the last two letter designations (QT) instead of (NR) mean the dealer found a different type of solvent cause she found a "match" before I was finished giving her the whole list of letters? In short, does Yamaha make different types of carb solvents with letter designations so nearly identical? AAAAH! Please help, I'm losing it here! Thanks in advance folks. Christopher.