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Engine Braking

Discussion in 'New Riders and Riding Tips' at netrider.net.au started by aste9974, Aug 15, 2011.

  1. Is it that bad for your engine? What parts does it **** up?



    Braking is cheaper? (just replace pads/drums)????
     
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  2. No, you're meant to engine brake when driving a vehicle with a manual gear box.


    Why do so many people think engine braking will ruin their gear box?
     
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  3. Yes because needlessly exchanging forward momentum to heat via the brakes is much cheaper then coasting and downshifting ;).
    :angel:

    Ok ok, truthfully there is nothing wrong with engine braking.
    Just try and blip the throttle to match the engines revs to the gear you are in for the speed you are doing - not only is it more comfortable to be on the bike with smooth changes, its always kinda cool when you get it right even if you do every time.
    That also all but prevents any strain on your engine when you downshift and clutch out.
    Might take a second or two to get it right, but eventually itll come natural and be a blink and you miss it effort.

    Unbalanced and jerky downshifting however, can have a tendancy to stretch cam chains and drive chains unnecessarily, and runs the risk of locking up the rear wheel, but you learn by doing so give it a try ;).
     
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  4. havent heard this one about the cam chains before. cant see why it would do that.
     
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  5. "blip"????
     
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  6. There are conflicting opinions.

    Some old school mechanics and engineers will tell you that engines make the car (bike) go and brakes make it stop, and if you use the engine as a brake, you're not doing it any good. Others disagree.

    Trucks go for a long time, and they use engine braking a lot. They have a specific device to dramatically increase the amount of engine braking, just to make it more effective.

    There are potential issues with anything that makes very sudden and dramatic changes to the engine speed, but engine braking / compression braking done in a sensible way shouldn't do that.

    Engine braking can drag the revs up over redline and blow the motor, on an engine that's otherwise protected by a rev limiter.

    Making a conscious effort to use the front brakes, little rear brake and not a lot of engine braking can wear the front tyre more and the rear less. That can maybe help if you plan to change them as a matched set and you want to extend the life of your rear tyre a bit. But that isn't what you're asking - "Does it harm the engine?"

    There are certain specific circumstances where it might, but done sensibly, it probably won't.

    A though for you. A surprising number of engines which blow up on the dyno, do it after the throttle has been shut and the engine is winding down. Many smarter dyno tuners / operators pull the clutch as soon as the run is over and let the engine return quickly to idle, or at least, low mid-range revs. Now it could be that the harm was done while the throttle was open and it just went critical a few moments later, but ...

    Racing two stroke engines are a special case, but they should not be left turning at high revs with the throttle shut. No air/ fuel means no oil for the mains, big end or little ends. The incoming air/fuel mixture also helps cool the piston, even if it's followed by a bang. Shut the throttle at big revs and leave it shut at your peril. They can run at small throttle openings, or with a blip here and there (like to down-change) or you can (if you have the presence of mind) stick your thumb in the inlet trumpet and half open the throttle - causing the engine to run very rich on over - run. Some people manually adjust the mixture screw for long straights, and then adjust it back at the end. (Yes, I'm talking gokarts. They are a special case, but interesting.)
     
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  7. Aren't there a few 2T that have a neutral at every half shift, ie, 1 n 2 n 3 n 4 n 5 ?
     
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  8. Rightly or wrongly I was taught very early to use the gears to slow down, brakes are for stopping.

    Even when I drive an auto I change down when I simply want to slow down, particularly going down steep hills. Nothing is quite as scary as running out of brakes on a long down hill winding road.
     
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