When should I change my air filter?
Well, look in the service book, it tells you. It could be about 12,000 miles or two years but yes, it depends! Your riding environment has a big impact on how long your air filter remains in an optimum condition. Some environments will start to clog up the filter, reducing the airflow into the engine, much quicker than others. Heavy traffic, wet weather and dusty roads will all reduce the scheduled service life of your air filter.
If the filter below is 12 months old and it comes from a bike ridden for an hour everyday in heavy traffic all year round – it’s fair to say it’ll be pretty filthy. This definitely needs changing now, well before its scheduled 12,000 miles. I wonder what the rider’s lungs look like?!! For comparison, check out a new filter next to an old one (photo above). If however, you are only riding in the glorious Essex countryside, avoiding wet weather and dusty roads you may well get 20,000 miles from the filter. Don’t change it just because the service schedule says so.
Should I go for a K&N filter, an after market one or can I clean my old one?
Yep, you know it, it depends! Doesn’t it always? K&N filters aren’t cheap but the are supposed to have a much longer service interval than a standard filter plus you can clean and reuse them! So, buy one to last forever? Well almost, maybe. You still need to buy the proper K&N refresher kit which adds to the overall cost (albeit only £10-15 for several cleans). Note that when cleaning a K&N filter you’ll need to dry it out before re-oiling and refitting, which can slow a quick service plan. Do your sums and see what works for your model and how long you think you’ll own it for.
After market filters work just fine and as said earlier, if you are clean dry countryside riding only, it’ll last ages. They are generally more affordable too. If your old filter isn’t too dirty you can clean it up a bit for a few more thousand miles.
But are K&N filters better – like make my bike faster, from the increased air flow? Well maybe. But the extra air flow can also make a carburettor bike run lean. The real question here is are you that good to notice the difference? And as a wise young man recently said, ‘you’ll probably go even faster if you lost a few pounds instead!’