23 Aug 2010

De-stressing your bike's engine

What would you do if your bike's pick up has reduced noticeably and the engine feels a little too stressed after it's just back from the mechanic's?  Sometimes mechanics tune things slightly wrong, and here are a couple of things you can try to fix the bike yourself:

Reduce the idle speed of the engine if it's too fast.  Recommended idle speed for your bike, how to change the idle speed, etc. vary for each bike.  For Honda Unicorn, the recommended idle speed is 1400 ± 100 rpm.  You can adjust the idle speed by adjusting the knob shown in the picture.  One thing to keep in mind while adjusting idle speed is that, you should ride the bike for 2 or 3 kilometers to warm the engine up before setting the idle speed.



Loosen the clutch cable if it's too tight.  But how do you know if the clutch is too tight?  A few symptoms I know of are:
  • The bike's pick up is slower than usual.
  • The engine stresses more than usual even at slow speeds.
  • When you have to use the clutch very frequently -- for example in stop-and-go traffic -- because the clutch is too tight your fingers become sore quicker.
You can loosen the clutch by adjusting the nut shown in the picture.  One good thing about this nut is that you don't need a spanner (or wrench) to adjust it; you can simply use your fingers.

11 comments:

  1. My bike stops as soon as i slow it on the breaker. It is 3 month old unicorn and it has run 2690km . what should i do so that it does not stop?

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    1. See if your idle speed is not too slow? Also, using petrol from Bharat Petroleum made my engine run smoother. (This was all several years ago; I am not sure how well they apply to new Unicorns.)

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  2. Thanks !! Idle rpm was a bit concern for me as my new uni 150 shows rpm of 1.1 when started which goes up to 1.9 after few km run. So now I have got the idea to set it after few km run..

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  3. Unknowingly i played with the idle screw and raised upto 2 k.later i tried to make it default..but i cant.
    I felt that my mileage reduced to 40 kmph from 55 kmph..
    Does idle rpm affects the mileage?? How will i regain that optimum mileage for my unicorn 150??

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    Replies
    1. Ask a mechanic to reduce the idle RPM if you're not able to do it yourself. It shouldn't take more than a minute or two.

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  4. If the ideling varies does engine mileage changes or not?the ideling at 1k,it may increase or decrease the mileage???

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    1. Idling at a higher RPM would consume more petrol, yes. But it's hard to say if that will result in a noticeably lower mileage. Depends on how long the engine runs idle. If you tend to turn the engine off as soon it's not needed, you may not see much of a difference.

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  5. is there any recommendation for petrol type or additives for smoother engine on unicorn 150?

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    Replies
    1. Usually additives don't make much of a difference. When I used to have a bike, I found (after trying many different fuel brands) that Bharat Petroleum's petrol was much better than everything else. Maybe give that a try?

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