fouled plugs?

Blake Williams · 02-11-2008, 12:02 PM

I posted about two weeks ago concerning a problem with my bike under the title of "COLD NIGHT BIKE WONT START" The short story about that post was that I let my bike sit over night w/empty tank of gas and the temperatures got very low. The little bit of fuel went bad and fouled the plugs when I tried to start it the next day. As instructed by the nice people who responded, I took the plugs out and cleaned them up ( they were dark and wet). I filled the tank back up with premium, a little bit of fuel/ carb cleaner, and half a bottle of octane. The bike fired right up and I put about 40miles on it that day. It ran really well and I could even notice a difference with the octane additive: HP wise and also the motor ran a little warmer. Then I put the bike away indoors in a warm garage. The next day I went to start it and Im back to square one. The bike barely pops and backfires every once in a while. So my question: Once fouled plugs always fouled plugs? Even though I cleaned them up and they ran fine for a day of stop and start errands could sitting for a few days foul them up again if they had been fouled once? These were not new plugs by any means, just cleaned. I have a new set to put in, the most obvious answer would be to start there. Until this problem of sitting out over a cold night this bike has run without flaw. PS anyone have any trick to the front two cylinders access any way I see it the radiator needs to swing up etc and its a tight fit with sockets and extensions. Thanks everyone.

squirrelman · 02-11-2008, 04:35 PM

You're right, the rad needs to swing forward, and be very careful not to bend rad fins when changing plugs in the small area there. Since you have new plugs ready, gap them to .030" ; install and most likely solve your starting problem.....
Be certain the plugs are the proper ones recommended for your bike, however in cold weather (only) you could use a one-step hotter plug (see service manual) to reduce fouling in cold, slow speed conditions.

For cleaning plugs use carb/brake cleaner spray and brass or steel wire brush; never use any sandpaper.

Lube plug threads with oil, grease, or never-sieze before installing.

When starting use as little choke as possible to avoid flooding and reduce amount of choke as soon as possible once motor fires.

Just jamming choke FULL on does not work best on some bikes.....

nozzle · 02-11-2008, 08:50 PM

Blake:

It may be that one of your carb floats is not floating all that well and fuel is flowing into the combustion chamber. One way you might check this is to turn off your fuel and let the bike run dry. See if you foul the plugs the next morning after the fuel is off. Then you may decide on fuel or ignition system diagnosis paths with some insight.

Or at least that is something I'd try.

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02-11-2008, 12:02 PM	#1 (permalink)
Blake Williams Junior Member Join Date: Nov 2006 Last Online: 05-02-2008 11:27 AM Posts: 20 Thanks: 0 Thanked 0 Times in 0 Posts	fouled plugs? I posted about two weeks ago concerning a problem with my bike under the title of "COLD NIGHT BIKE WONT START" The short story about that post was that I let my bike sit over night w/empty tank of gas and the temperatures got very low. The little bit of fuel went bad and fouled the plugs when I tried to start it the next day. As instructed by the nice people who responded, I took the plugs out and cleaned them up ( they were dark and wet). I filled the tank back up with premium, a little bit of fuel/ carb cleaner, and half a bottle of octane. The bike fired right up and I put about 40miles on it that day. It ran really well and I could even notice a difference with the octane additive: HP wise and also the motor ran a little warmer. Then I put the bike away indoors in a warm garage. The next day I went to start it and Im back to square one. The bike barely pops and backfires every once in a while. So my question: Once fouled plugs always fouled plugs? Even though I cleaned them up and they ran fine for a day of stop and start errands could sitting for a few days foul them up again if they had been fouled once? These were not new plugs by any means, just cleaned. I have a new set to put in, the most obvious answer would be to start there. Until this problem of sitting out over a cold night this bike has run without flaw. PS anyone have any trick to the front two cylinders access any way I see it the radiator needs to swing up etc and its a tight fit with sockets and extensions. Thanks everyone.

02-11-2008, 04:35 PM	#2 (permalink)
squirrelman Senior Member Join Date: Jul 2006 Last Online: Today 07:23 AM Location: barf-a-load, ny - Find Me! My Ride: '86 VFR 700Fs (3), NT 650 HAWK (3) Yamaha Radian Yamaha 1966 YL-1 '97 VFR 750F '88 VTR 250 View my Photo Gallery Posts: 802 Thanks: 4 Thanked 14 Times in 14 Posts	You're right, the rad needs to swing forward, and be very careful not to bend rad fins when changing plugs in the small area there. Since you have new plugs ready, gap them to .030" ; install and most likely solve your starting problem..... Be certain the plugs are the proper ones recommended for your bike, however in cold weather (only) you could use a one-step hotter plug (see service manual) to reduce fouling in cold, slow speed conditions. For cleaning plugs use carb/brake cleaner spray and brass or steel wire brush; never use any sandpaper. Lube plug threads with oil, grease, or never-sieze before installing. When starting use as little choke as possible to avoid flooding and reduce amount of choke as soon as possible once motor fires. Just jamming choke FULL on does not work best on some bikes..... __________________ "Machines are the tools of freedom." :Cyrus Eaton " Goin' to Hell in a bucket, but at least I'm enjoyin' the ride....... "

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02-11-2008, 08:50 PM	#3 (permalink)
nozzle Uber Noz Join Date: May 2007 Last Online: 10-04-2008 03:32 PM Location: Southern Maryland - Find Me! My Ride: 07 RWB 'ceptor View my Photo Gallery Posts: 1,428 Thanks: 3 Thanked 8 Times in 8 Posts	Blake: It may be that one of your carb floats is not floating all that well and fuel is flowing into the combustion chamber. One way you might check this is to turn off your fuel and let the bike run dry. See if you foul the plugs the next morning after the fuel is off. Then you may decide on fuel or ignition system diagnosis paths with some insight. Or at least that is something I'd try.