fouling #2 plug??? WHY!!

I know why, It’s getting way to much gas on the #2 cylinder when I pull the plug its soaked. When I ride about 5 miles keeping the rpm's at about 5K it fouls, I replace the plug and its good for another 5 miles, or as long as I keep the idle low.

I have color tuned twice and it is still fouling out. I just don’t understand what’s going on. The only thing I could see is one of the jets was a little messed up when I was rebuilding the carbs. But is there anything I am not looking at?

 

Maybe a bad #2 plug wire or plug cap. Just something to check out.

 

+1 or maybe the coil.

 

I was thinking the same thing but it will not foul while at idle... thats what throws me. also I dont think its the coil because the #1 is running just fine, and if it was the coil wouldnt i be seeing problems with both plugs?

 

I dont know if you will see it in both plugs or not? Sounds like it just not getting enough juice. Maybe the TCI could be at fault too? Sart from the plug and work your way up from there. Plug, cap, wires, coil, TCI... or atleast thats how I would tackle it.

 

ok so my next question. is there anyway to replace the wires from the coil?

 

I dont think so... I believe you have to replace the coil... Might as well get that DC1 or whatever everyone is switching to if your going to replace it though

 

Look at the Links section……
1. XJ DIY & How To's

Last link on the first page…..
Replace stock Yamaha ignition wires

Or just click on the following link….
http://www.xs11.com/tips/repair/repair24.shtml

 

Well there you have it! and that's some good info!

 

thanx nick you get my ATTA BOY! of the day.

 

Yeah if you do replace the wires in the coil by grinding the housing away and what not, be VERY careful on the right hand side wire. That little "spike" that you solder onto is very delicate and small. I nearly ruined a coil because of that thing. I was successful though. I coated the area I ground away with JB Weld after installing the wire and that baby is sealed up tight!

 

I think i got it fixed. i went to the store and got ANOTHER set of plugs and colortuned AGAIN. I had it set a little rich and when i turned it down it seemed to have some effect.

 

here's to hoping you just had not colortuned it correctly the last time.

 

ok well it ran ok for about 150 miles and guess what.... fouled again. this time it is REALLY black and almost looks like its oil. Im going to try to replace the spark plug boots and put a new plug in.

The 1&4 cylinder plugs look fabulous. but 2&3 plugs look black as coal(the #2 is the only one fouling however). could a improper sync do this?

 

I think I would be leaning toward a#2 coil problem. Could'nt hurt to check the resistance on the primary and secondary side. Just search coil resistance and you should find all the info you need to run the checks. Also make sure the coil has a very good ground. You could allways swap the coils. Swap the 1-4 coil for the 2-3 coil and ride it that way for a few miles. If the plug fouling goes to the 1-4 plugs, Then you have found your problem, The coil. If not, than we will have to dig a little deeper.

 

not a bad idea. I just dont want to have to buy a new coil at all.

 

You say it looks like oil? Could it be that you've got bad rings on the #2?

 

only 1 cylinder reads over 100 psi. I doubt I have very good rings on any of them ill just ride it till it breaks. I think its useless to put that much work into a 200$ bike.

It has been setting for about... 3-4 years and before that it wasn't ridden very much. Im thinking it might have some oil leaking by somewhere but it just needs to be "broke in".

 

Well I switched the coils last night and it has the same problems. Its not the coils. Im going to tear into the carbs one more time and replace the main jets. HOPEFULLY that will fix my problems.

 

Take a close look at the number two carb. The fuel in the enrichment circuit may leaking past a bad o-ring. Make sure the lever and the acuator fully seats. Even just a little bit up could cause a rich condition. The fuel level in the fuel bowl may be a little high also. A difference of even 1-2 mm can cause strange things to happen.

 

yeah, I would swap the coils first and see if that changes the plug that is fouling.

 

ive concluded the rings in #2 are prolly gone. im just going to run 20-50W and hope it clears up i dont really want to rebuild.

how hard is it to find rings and how much do they cost?

 

Depending on how long the bike sat befor you got it. The rings in number 2 may be frozen up also. It may take a while for them to free up. How many miles on the bike? How long di it sit before you got her. Rings generally last quite a while, as long as the bike has been taken care of. Is the oil level correct. Check the oil while on the centerstand. It should be towards the upper part of the sight glass. If it is over full. This could be a contributing factor.

 

Im also hoping that it will clear up after a while. I THINK it only has about 10K miles on it. It was probably set up for about 3 years or so. Before that I doubt it was ridden very much for about.. 6 years. The oil in it when I bought it was VERY BAD and I replaced it, and now ive run some sea foam in the oil while in idle to get some more of the gum out of it. As soon as it warms up I plan on riding it for about 3 hours strait to see if i can get it loosened up a bit.

 

I think I asked this in another thread, but doesn't the vacuum line for the petcock go to #2 cylinder? Why not remove the hose and drive around on "prime" for awhile to see if it clears up? If it does, I'd wager you have a leaky diaphragm in the vacuum petcock.

 

Or you could switch it over to another cylinder and see if that cylinder starts fouling. That way you don't risk having gas in your crankcase.

 

negative...
that vaccum line from intake to petcock is on the three.

 

yeah I have it going to three not 2. I really think its getting oil. It looks a lot like a 2 cycle plug when I pull it really black and wet. I think Im just going to put some miles on it and keep changing the plug every time it fouls, to see if it wont just clear itself up.

 

OK, I love 20 questions!!
Here goes...

Have you checked the spark?
How does it look? Blue, orange, purple...

When the carbs were last removed and "one jet was messed up" what was done to fix it?
Was said jet on number 2?

What are your compression readings all accross the board?
You say low, but how low?

What kind of oil is being run, how old is said oil?

When was the last color tune?
How far OUT are you now?

Besides the poor plug condish how does she run?

Last sync was when?
Not like the last question even is relevent...but you never know.



Please pass all completed tests to your right when completed class!

 

#1. all blue in #2 its wierd it goes from blue to yellow and back to blue.
#2. yes one jet was just mangled up looked like it had had "vice grip treatment by a PO" nothing was done to fix it as it looked like it would work just ugly. I really dont know what carb it went back into.
#3 about 75 psi cold across the board besides one being right above 100 (i have a old compression gauge i dont know if it works correctly)
#4 i colortuned yesterday.
#5 Not far at all
#6 With a good plug it runs like a spotted ape
#7 sync about 2 weeks ago.

Im in college and usually do poor on my tests

 

MmmKaayyy... WTF does that mean?!!? :wink:

 

Well guys I fixed it today. Busted the carb apart for the 4th time re colortuned and sync and rode it for about 30 miles and guess what, no oil on the plug. I just wish I knew what fixed it. THANK YOU VERY MUCH! for all of your guys help!!

I got the plates for it yesterday and as soon as I get a new front tire I'll go get inspected.

 

probably some crap blocking the high speed jet fell out when you pulled the carb apart again. Same thing happened to me and I've wondered about it for years...