Friday, January 2, 2009

Honda Unicorn - Run In Guide.

Well, first of all i'm not going to write a 'run in guide' or write any useful text that answers the question ' how to run in a Honda Unicorn ?' or write something that will be useful for someone who googles ' Honda Unicorn run in method'. The title and the previous lines are purely my attempts at SEO.

Moving on, i decided to write about how i treated my Honda Unicorn, during the 'run in period' ie. the first 1000 kms.

I did not follow the usual run in method that is generally followed for new bikes( no surprises here) and I definitely did not follow the run in instructions from the Honda user manual ( which requires me to ride at low engine rpm with no sudden acceleration etc. for the first 500 kms).

Let me first talk about why the engine has to be 'run in' or 'broken in' ( the way i did).

In a brand new engine , the cylinder walls and the piston rings haven't really spent much time together ( cos' they just met each other). So the distance/space between them is not even, and the action is quite rough. It is 'this' factor that decides the life of your engine, piston rings etc. and how long the default compression will last (ie. if you screw up the rings, your cylinder will begin leaking compression which will lead to reduced power and so on..).

To make sure we get ideal engine performance, proper mating of the cylinder walls with the piston rings is really really important.

The regular suggested/followed way for 'run in' is actually the 'crawl in' method IMO.

The usual method - Run the engine at very low rpms, never take it beyond 40-50% of maximum load, ie. on our Indian bikes we'll need to keep the engine below 4k rpm and 50kmph (prolly') for the entire duration of the run in period (1000 kms). The 'crawl in' pundits claim even breaching the rpm/speed limit once could screw up the run in/engine. Which according to me is total BS. Also i think this technique does no good to the engine period.

Motoman's run in method - Read the original article here.

This is an extreme run in method that claims that the best way to prep an engine for its actual life is to 'break in' hard. ie. the piston rings mate best when the engine is run hard in the few kilometers. (the exact reasons for this are given in his article). After which an engine oil change has to be done to remove the micro metal dust that accumulates in the oil as a result of hard break in. So this way, the run in is done with in the first 20kms.

And, this is what i did and also suggest.

My way was a mix of these run in methods, and i think is the best for our Indian bikes ( obviously)

- I made sure i took the engine through its entire rpm range in the first three gears at least, this was when the engine had done less than 50 kms.

- I rode at a 75-25 mix of sedate under 50 kmph riding + harsh throttle bursts, when sometimes i touched 80+ speeds, till the 600 kms on the odo.

- I made sure i did not ride at a constant engine rpm, this is the most important part of any run in. Prolonged constant rpm riding causes engine glazing( google to find out what engine glazing is) and in short fucks up the engine regardless of your run in technique.Most of the riders who follow the instructions in the manual end up doing this, cos the manual says 'no sudden acceleration'.

I wanted to change the engine oil at 100kms but then couldn't really find the time, also i was a little short on money then so couldn't invest 200 bucks on engine oil. but, I think this is necessary cos' a new engine always sheds metal dust into the oil. You'll do better without such dust in your engine lubricant.

After 600 kms, i went on a 450 km ride to Yelagiri, to complete my 'run in' period. The average speed on this ride was 70kmph with short bursts of 90kmph. Made sure i kept varying the engine RPM. The bike performed beautifully on this trip and there were no heating issues even on continuous riding ( i expected some trouble).

Got my bike serviced the next day, ie. got the engine oil changed. I feel the engine has become a little smoother with the new oil and the gear shifts are definitely getting better ( starting to get that nice 'click' on shifts now).

I'm happy with the run in method i followed and think my engine is well set right now, i decided to do a small solo ride yesterday night at 11pm on the Maduravoyal byepass road, the roads were totally empty so i tried topping out my bike on a long straight stretch, i could do 110kmph( speedo indicated) with ease, ie. with no ripping in lower gears and by just opening the throttle from 80kmph in the fifth, i got to 110kmph in no time and the bike looked good enough for a good 5-10 kmph more.

Check out this article which describes the tech stuff related to engine break in. Very good read.

Totally open for discussion on this in my comments page. Indulge yourself on any engine related talk.


nidhish said...

man,y did U choose ece in the first was good..U shud try writin 4 some auto mags.. ;)

Rayees Ahamed said...

That was a good read dude,

it is always not important which brand we buy (Unicorn or Apache or Pulsar or any other equilvalent 150+ engines), but it always matters how do we handle it.

thanks for the tips, it never occurred to me that top speed can be affected by gear shift timings, though i have managed 115 kmph in Apache ..

Rayees Ahamed said...

My friends have told me, Unicorn is much smoother than its rivals, but little heavy that slows a bit of its pick up i guess (old model)..

Guru said...

Yep, we can prolly' touch a tad higher speeds if we take the bike till the revlimiter in the first four gears, that way we'll get there quicker. To register the same speed from a 5th gear roll on starting at 60kmph, it'll take time and lots more road.

ya, the Honda engine is a lot more refined, the ride is super smooth and relatively vibe free.

-=A.R.N.=- said...

Like Rachel (from Friends) says, I'm an engine virgin.
I've no idea on run/crawl ins, but what you said makes sense.

In any case, I never follow the instructions on anything I buy either...manufacturers assume that users are total idiots, don't they?

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Bhupendra Kr. said...

Honda CB unicorn is one of the most powerful bike of 150cc segment.It got perfect styling,excellent handling and smooth gear-shifting.These are the symbols of a perfect bike.

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