Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

K&N filter and slip-on

Discussion in 'Modifications and Projects' started by austrooper, Apr 29, 2016.

  1. Hi All,

    I ride a Honda CB500X. I have a Two Brothers Slip-on. I have recently purchased a K&N airfilter. In my wanderings around the net I read that you shouldn't combine these two mods as the engine will run to lean (or rich) and could cause some damage.

    Does anyone have advice in this, does it really mean that instead of the engine lasting for 100,000 it will last for 80,000 or will it really have an impact?

  2. #2 icemaker, Apr 29, 2016
    Last edited: Apr 29, 2016
    Yeah, you would usually need a power commander or similar to sort out potential fueling issues. There should be some info on the net about it or chat to your mechanic
    • Agree Agree x 1
  3. Really depends on the ECU itself. Normally they have a target air fuel ratio and can adjust the fuelling to suit the conditions. Although I have no idea how complicated or simple the Honda one is (probably more likely to be pretty simple though). That being said if your ECU is capable of doing this then the flip side is no performance benefit with your mods.

    Honestly I wouldn't expect the factory air filter to be that restrictive that your going to cause any real damage. At the end of the day your decision whether it's worth the risk for whatever benefit there is (if any).
  4. The performance benefit of a k&n over standard would be fairly minor so its not worth the cash especially if you need a power commander to have it running properly.
    If it was me Id just chuck the exhaust on and run with that.
    • Agree Agree x 2
  5. The major benefit of the k&n comes from being able to wash it out and reuse it, rather than any performance boost.
    • Agree Agree x 1
  6. So it is just a myth when products such as power commanders have maps to suit slip on exhausts and k & n filter combinations. Basically stock filters do the same as a k & n, always thought those filters allowed more airflow due to the gaps in filter mesh being bigger.
  7. iv'e read the same and was also curious, i have slipons and K&N and was also thinking of fitting a power commander, i get a bit of back firing "popping" when coming down through the gears. nothing too serious though .
    one thing to bear in mind if you do it will more than likely also affect your insurance if you do fit one. if i fit one my insurance goes up by approx $120 - $140 a year.
  8. The K&N filters do flow more air ... but that's irrelevant if the engine isn't actually sucking more air than the stock filter can flow. The same goes for the exhaust, if the engine isn't trying to push more gas out than the stock pipe will flow then a more open muffler won't gain you any HP. Unless the engine being restricted by the stock gear. most gains will be found right at the top end of the rev range and you'll need to adjust the fuel/air mixture to compensate for the additional air going into the engine.
    The one thing you can be certain of gaining with a K&N filter and a free flowing slip-on is noise. Induction noise from the intake and exhaust noise from the tail pipe.

    If you keep the bike long term you can save some coin on paper filters by using a K&N, but they're not as good at handling really fine dust as the stock ones. If you never ride dirt that's not a huge problem, but if you do ... not so great. I have one on my Strom and emailed the company requesting the actual test data showing how much they flow, how much dust they retain, how much and what kind of dust they let through and how long they last until blocked (standard product tests done on all air filter elements). They straight up refused to provide the data that would have confirmed (or debunked) their product claims. Frankly, I'd never buy another one. If the company refuses to prove their claims are valid ... are they really valid or just marketing bunk?
    • Like Like x 1
    • Agree Agree x 1
  9. Don't you enjoy the popping and crackling? It's probably not an issue, lots of bikes do it stock. I wish my drz would do it more.

    Power commander on a learner bike is turd polishing.
    • Like Like x 1
  10. I would have used the phrase "over investment", but yeah.
  11. mate i love it lol :) but i don't want it causing any damage, recon it would look pretty cool in the dark too, but it's a bit too far to lean back and see.
    seen some vids of some bikes flaming through the pipes, but also read it's not good for the bike too...
  12. It often means there's an air leak in the exhaust somewhere and letting hot unburnt fuel vapor ignite. It's not impossible for it to split your muffler can wide open.

  13. or you've left your air injection system intact :)
  14. Interesting views. On a similar topic, is it worth purchasing a power commander 5 just for a slip on ?
  15. In my opinion, no. Your bike, your money, but I'd spend it elsewhere.
  16. If the tuning is right it still shouldn't be popping and farting.
    • Agree Agree x 1
  17. What would you suggest?
  18. Get the bike tuned properly. Not so it's "in spec", I mean properly. Next is suspension. You don't need to spend a fortune, something as simple as a fork brace can make a big difference to how your bike handles without over spending. Another tip is to get a gym membership and use it. What's that got to do with anything you ask? Simple. It's a ton easier to shave 5kg off your arse than off the bike and that's 5kg the engine doesn't have to waste horsepower trying to move.
    Next tip, buy a tyre pressure guage and use it. Keeping your tyres properly inflated also reduces wasted power and improves handling.
    • Like Like x 2
  19. Oh, and for f£%k sake don't go drilling your air box. It will just end up costing you a new airbox and make the bike loud for no gain in power. Airboxes are designed to do a job by people who do know what they are doing. Trust them.
    If you REALLY want to spend a few bucks buy some iridium tipped plugs of the right size and heat range. They won't make any noticeable difference to power output but you won't need to replace them for 60,000 odd kms so you'll save money.
    • Like Like x 1
  20. Haha! Yeah not interested in hacking at my air box, I've read stories of people not being able to tune their bike properly because of that