Spark plug fouling repeatedly - LTZ 400
#1
Spark plug fouling repeatedly - LTZ 400
Howdy- I'm trying to figure out why the spark plug on my 2004 Suzuki LTZ 400 has begun fouling.
I had the quad in the shop a few weeks ago, and they replaced the plug and explained that the spark plug was fouled. Great, it was back running tip-top.
I rode last week each day Monday through Saturday. Then, Saturday afternoon, it wouldn't start. Upon removing the plug, we found that the new plug was fouled -- all carbon-ed up. What's up w/ that?
The machine is stock except for some nerfs. What ideas/suggestions do people have?
Grassyass
D-Day
I had the quad in the shop a few weeks ago, and they replaced the plug and explained that the spark plug was fouled. Great, it was back running tip-top.
I rode last week each day Monday through Saturday. Then, Saturday afternoon, it wouldn't start. Upon removing the plug, we found that the new plug was fouled -- all carbon-ed up. What's up w/ that?
The machine is stock except for some nerfs. What ideas/suggestions do people have?
Grassyass
D-Day
#2
Spark plug fouling repeatedly - LTZ 400
You are either running to rich, or you are burning oil.
Check your air cleaner, clean if dirt. The carb could be sticking and making it run rich also.
Does it seem to be losing oil and has no leaks. Oil could be getting past the rings and into the combustion chamber, or leaking thru the valves.
Does it seem to be smoking? White-ish gray would be running to rich. A black/dark gray would be burning oil.
Rob
Check your air cleaner, clean if dirt. The carb could be sticking and making it run rich also.
Does it seem to be losing oil and has no leaks. Oil could be getting past the rings and into the combustion chamber, or leaking thru the valves.
Does it seem to be smoking? White-ish gray would be running to rich. A black/dark gray would be burning oil.
Rob
#3
#4
Spark plug fouling repeatedly - LTZ 400
Originally posted by: RobBob91
You are either running to rich, or you are burning oil.
Check your air cleaner, clean if dirt. The carb could be sticking and making it run rich also.
You are either running to rich, or you are burning oil.
Check your air cleaner, clean if dirt. The carb could be sticking and making it run rich also.
Does it seem to be losing oil and has no leaks. Oil could be getting past the rings and into the combustion chamber, or leaking thru the valves.
Does it seem to be smoking? White-ish gray would be running to rich. A black/dark gray would be burning oil.
Rob
Does it seem to be smoking? White-ish gray would be running to rich. A black/dark gray would be burning oil.
Rob
Thanks for the reply!
#5
Spark plug fouling repeatedly - LTZ 400
Originally posted by: bombrider04
Well what octane gas are you running in your quad and are the spark plugs gapped corectly...Rob if what you suggested doesn't make a difference wouldn't you think the cdi could be on its way out or some other short electrically.
Well what octane gas are you running in your quad and are the spark plugs gapped corectly...Rob if what you suggested doesn't make a difference wouldn't you think the cdi could be on its way out or some other short electrically.
Hmm, well, I dunno what the "cdi" is... I suppose it could be going out, but, what is it? Yup, it is quite possible that there is an electrical short on that thing, too. I'll give it a look-see for any obvious electrical issues (bare wiring and what-not).
Thanks for the suggestions!
D-Day
#6
Spark plug fouling repeatedly - LTZ 400
You should clean the air filter every few rides. Get some hot soapy water and was it really well in it. Don't ring it out but use gentle squeezing to clean it. Rinse it well and shake out as much water as you can. Place it infront of a fan till dry. Oil it after it is dry with a good quality foam filter oil. I put alittle bit of oil in a ziplock bag then put the filter in and squeeze the oil into the filter. I would recomend going to the gas station and getting some fresh gas also. The gas in the tank may be alittle old. Try all that first before messing with the carb.
This would also be a good time to do a full maintanence check on the whole machine. Get good quality Motorcycle oil and a new filter, grease it and just check it out. I wouldn't worry about the CDI or anything like that until you check out what I said first. Always check the little things first.
Rob
This would also be a good time to do a full maintanence check on the whole machine. Get good quality Motorcycle oil and a new filter, grease it and just check it out. I wouldn't worry about the CDI or anything like that until you check out what I said first. Always check the little things first.
Rob
#7
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#8
#9
Spark plug fouling repeatedly - LTZ 400
the manual says you can use 87 but recomend using 91 or higher. as for the cdi it controls the spark timing and revs,but if the timing chain is stretched it could change the way it fires, if it has a bad spark it could be the igniton coil, the generator, the pickup coil or the cdi, does the quad use any oil? might be valve seals leaking, but to me it still sounds like s carb problem