New air filter and uneven idle

Took out the Stock filter and changed to a Hiflo HFA1911 now the idle wavers up and down slightly.
I have seen this happen at high altitudes but I'm near sea level.
The Hiflo looks almost identical to stock, has anyone had any experience with this?

I use the Hiflo and haven't had that problem on two ST1100s. How does it run without a filter and with the old filter back in? Balanced the carbs lately?

Sly, the filter change just amplified what is already wrong with the bike having the idle slightly fluxuate...........idle mixtures and carb sync need to be done.

It should be running a bit leaner with a new filter, if the old filter was clogged. What happens if you leave the choke on a bit ? Does that smooth out the idle ??

BTW, I use the HIFLO filter. replaced mine a while back. I think I had about 20K miles on the old filter. I could see through the old filter, but when I blew it out with some low pressure air, a lot of dust / dirt came out. From now on, I'm replacing it every 12K miles

And, exactly how many RPM's is the idle varying ??

I would check the carb sync. If that looks good, I wouldn't worry about the idle, unless it is varying a lot more than 100 RPM.

Jim Van said:

I could see through the old filter, but when I blew it out with some low pressure air, a lot of dust / dirt came out.

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Switch to a K & N and that will be less of a problem.

Jim Van said:

From now on, I'm replacing it every 12K miles

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You do that just to get me shaking my head, don't you?

I have neither the time money or inclination to swap out the filter that often. Maybe just maaaaybe if it were as easy as popping the hood on my old Chevy and pulling the top of the air cleaner...

As the filter clogs performance drops but filtration increases. Replacing the filter at that point would be like riding a new motor. That would be even better than the New Bike Feeling I get after an oil change! More