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Raising idle rpm safe?

Discussion in 'Maintenance and Servicing' at netrider.net.au started by mogley, Apr 10, 2012.

  1. Hi all.

    I have a Ninja 250r and raised my idle rpm from around 1,300 rpm stock to 2,000 rpm using the idle adjustment knob. I find this makes the bike coast with no throttle nicer which is handy for u turns and feels more planted for slow speed riding. Off the lights it takes off a little better as well.

    I have noticed though that the revs fall back to idle much slower and especially takes a while to get down to 2,000 from 3,000 and it sort of lurches when i force it to slow dow. using the brakes.

    I do however like the higher idle but want to know if this is safe for the bike?

    The bike is also jetted with Dynojet Stage 2 kit (prev owner).


  2. You may well find that it will overheat if stationary for any length of time. The cooling system will be designed to deal with the heat generation of the factory idle setting when there's no airflow over the rad but there may not be much margin to cope with the extra heat from the high idle.

    Otherwise no, there's no real downside for the bike. However, I'd suggest learning to cope with it as standard will do more for your riding long term than fiddling with the factory settings.

    That said, it does rather depend on how well it's currently running. Many bikes that have been fiddled with (eg Dynojet kit) run like a bag of crap.
  3. I think PatB covered it well, but just be careful going the other way, lowering your idle speed below standard can result in low oil pressure, something you want to avoid.
  4. To be honest, these sound like rider issues. Why do you want to coast with no throttle? Especially when conducting a u-turn, where you would typically combine higher rpms with clutch control and rear brake? If starting at slightly higher rpms helps you take off better at the lights, why don't you just take the slack out of the throttle cable and raise the rpms to 2000 before the light goes green, and leave the idle where the manufacturer's intended?
  5. As PatB says, there are potentially some issues with cooling. There is also a distinct lack of engine braking at lower revs, which is something of a double edged sword, it makes some things much easier and smoother.

    Driving schools often turn up the idle speed in manual cars for learner drivers, because it helps them make gear changes. (The revs don't drop as quickly so you can change more slowly.) I find them very strange and awkward to drive, they don't do what I want and expect. It's the same with bikes. With a high idle speed the bike doesn't do what I expect it to.

    Before the days of slipper clutches, road racers often turned up the idle speed to reduce the amount of engine braking, especially the ones who'd come from a 2-stroke background.
  6. Knee dragon makes some good points - stunt riders also turn up the idle screw for no hander or other types of wheelies....

    The part where I really agree with kneedragon is this:
    For the OP - for everyday riding I'd be suggesting you learn, or even master clutch/brake/throttle control (SHOCK HORROR!).

    Having the bike idling as high as you have it could be a hazard in certain situations as K.Dragon points out. These situations could easily be avoided by using all your bikes inputs properly....

    Unless you're a road racing or stunting god in which case you probably wouldn't be asking this question, then my mere mortal suggestion would be to put the idle back to stock and be at one with your motorcycle....after all, this is a big part of why we all ride, the freedom, the lack of things like Traction control or having 4 wheels to keep you upright. . . .save the wicking up of the idle for when you're a bonafide racer/stunter :)

    All said in lighthearted/sharing kind of mood of course ;) :angel:
  7. Can't see it hurting too much unless you turned it up way higher.

    But why not set the idle correctly and ride the bike correctly too?
  8. Uses more fuel
  9. #9 Seany, Apr 11, 2012
    Last edited by a moderator: Jul 13, 2015
    Does an apprentice carpenter have a large sheet of steel welded to his hammer, or is he expected to practice using the tool as it is designed until he can hit the nail on the head?

    Don't waste too much time thinking about that!

    Set the idle back to where it should be and practice your slow speed riding. The problems you have described have nothing to do with the bike and all result from poor riding skills. You need to develop your throttle control so you can maintain smooth control of the bike whilst balancing the throttle with feathering the clutch and dragging the rear brake during slow speed maneuvers. If you're in Vic then this would have been covered to some extent in your L's test (slow ride). Find a car park with plenty of space to practice riding very slowly and put in the hours until you get good at it. It'll be more time consuming than simply balming the bike but you will find it more rewarding in the long run. :)

    When you get goodat it, it'll look like this!