backfiring and not idling after cleaning filter

I am only a couple months into riding and have a 2004 ys450f. It was running fine last weekend, and this week I cleaned the air filter for the first time since I have owned it.

It has a Uni filter, and I think that everything is totally stock. I am not sure what kind of oil was used in the filter before, but I cleaned it with carb cleaner and oiled it with Notoil a few days ago. Upon starting it today, it would not idle and would backfire when revved.

Is there anyway that the combination of Notoil and residue of the previous oil could cause the filter to not pass enough air?

I have since learned that it is not a good idea to use Notoil on Uni filters, so I will have to buy some Uni oil, but I find it hard to believe that is this problem.

Any help is much appreciated.

I used no-toil on my uni filter, seemed to work fine for the 3-4 hrs I rode.

One thing I noticed was when using no-toil they don't want you to use gas, or some other types of filter cleaner. Theres a few they list are safe besides their brand so I don't think its a money grab.

Make sure you let the filter dry before applying the oil also, may seem like common sense but just checking.

Too Much Oil....

The two things that spring to mind are:

  • You didn't squeeze the excess oil out of the filter well enough, leaving it effectively clogged.
  • You didn't wait long enough for the oil to "dry" before you ran the engine.

The first point should be easy enough to follow. On the second, filter oils are usually blended with a carrier or vehicle solvent to make them thinner than they are normally so that they can more readily be worked into the element. This vehicle is expected to evaporate in a few hours, leaving a coating of the thicker oil in place on the membrane of the foam. If you run the engine too soon after servicing the filter, oil can be pulled off the element and block the air jets in the mouth of the carb.

I might also suggest that anyone who lives anywhere in Texas or the rest of the southwest should service their air filter after every ride day, two at the most.

Personally, I wouldn't use No-Toil if it was given to me, and I might not use it even if someone else did the work. Why? For one, it isn't easier than Maxima FFT or Twin-Air oil. There is no difference whatsoever in the oiling process itself, of course, but No-Toil claims easier clean-up. I don't find that true at all.

The cleaner they supply has to be mixed with water, and does not really break down and remove their oil very easily by comparison. By contrast, I have a covered pail with 2 1/2 gallons of mineral spirits in it that I reuse for months at a stretch. Preparation for the wash involves nothing more than removing the lid, the filter rinses clean in less than a minute, and there's no sink to muck out afterward. Hang the filter up and let it dry out by itself 'til the next day and oil it.

Second, No-Toil doesn't work particularly well. It dries out in a relatively short period of time to the point that it is neither very tacky, nor wet enough to catch and hold dirt effectively, especially fine dust. The oil is the only thing that makes foam filters work, and it has to have the ability to hold the dust particles that strike it, and absorb them well enough to expose it's surface to the next particle. No-Toil starts out fairly gooey, but dries out in only a matter of days to the point where it's much less effective. FFT stays flypaper sticky for months. I just installed a filter yesterday that I oiled weeks ago, and it was still tacky.

Either way, the filter oil has to be worked thoroughly THROUGH the entire mass of the foam element in order for it to be effective, so that every surface of the foam that is exposed to air flow is coated with it. Then the excess must be squeezed out so that no passageways are blocked by coagulated oil later. It's also a good idea to allow the filter to hang out somewhere for several hours to let any further excess drain off someplace other than the inside of the air box.

I am only a couple months into riding and have a 2004 ys450f. It was running fine last weekend, and this week I cleaned the air filter for the first time since I have owned it.

It has a Uni filter, and I think that everything is totally stock. I am not sure what kind of oil was used in the filter before, but I cleaned it with carb cleaner and oiled it with Notoil a few days ago. Upon starting it today, it would not idle and would backfire when revved.

Is there anyway that the combination of Notoil and residue of the previous oil could cause the filter to not pass enough air?

I have since learned that it is not a good idea to use Notoil on Uni filters, so I will have to buy some Uni oil, but I find it hard to believe that is this problem.

Any help is much appreciated.

What Gray said is, of course, great info. He about covered it all.

my experience was same as yours when I oiled a filter and installed in my stroker; almost would not idle, backfired, etc.

AND,

that's after I squezed excess oil out and let it sit for couple days. That was using UNI filter oil. Man those motors don't like anything restricting air flow. guess it was over-oiled.

Is there anyway that the combination of Notoil and residue of the previous oil could cause the filter to not pass enough air?

On that point, yes, that is a possibility.

Thanks for the help. I am sure that is it.

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