that 'water de-carb' shouldn't be performed. Water molecules are not compressable in an Internal Combustion Engine. Water turns to steam in combustion chamber, still steam can't be burned.. So when the whole mixture burns, it releases a huge 'shock wave' which dislodge some carbon deposits.. This shock wave can damage engine internal (just think of it, carbon deposit which is hard to remove even with drill grinder, were getting dislodged.. What kind shock wave is that? How much energy it has?) also, dislodged carbon particles can damage valves, piston may be other things.. Now plz don't tell he charged you for that so called de -carbonization. We all were thinking that de-carb was done manually, i mean, opening the head and doing the job. Don't ever go back to that jerk.

When my friend was going to sell his 45000km splendor, I had tried this water thing on his bike with his permission.
with in 1 minute the engine had become super hot and I had asked my friend to hold a white paper at the exhaust.
To our surprise some black smoke was emitted and carbon particles were seen on the white paper.
After that there was a slight improvement in the feel of the engine; it revved freely and a mileage test returned a 73kmpl on highway.
And he didn't sell the bike for 6 months.
But I never dare to do that thing on my Unicorn.

@ madhavparashar
Do u experiencing a low pick up? low Top speed? bike doesnt pull on UP as it should be?
If answer to all of these ques is NO, then your block is fine. because a worn out cylinder will have less compression, so less pick up, less mileage, bike will not pull frequently on up direction, and will let out white smoke.

As u said your mileage is good at 40 kmpl. I doubt on this. This cant be happen. Check your mileage again. Also check the oil level. If your oil level remains intact. Then, problem is not in your block.

As we said, black smoke indicates excess fuel is burning. If excess fuel is burnt off then bike will not give 40 kmpl. Both things cannot be happen at the same time. You know what i mean?
I went to the bajaj ASC and here the mechanic told that head is fine, dont open it off. Excess fuel is burning off.
Here is the conversation....here u'll hear two mech voice, first one is not so much experienced (told about opening head), after 48 seconds u'll hear another mechanic who is experienced one told the head is fine.... Listen to Audio conversation on P220

He said 40 mileage on black smoke is impossible. You have to fiddle with your carb.
He asked me whether it is carb or a pump one. I was not known about it, i told its carb. But the thing is he told head is fine and doesn't need to open. and thats what i was thinking when u told its black.

The things u need to do now!
1) Check if there is change in oil level.
2) Check your mileage from reserve to reserve and report back.

Pls clear all my doubts dont forget to answer each question. The more u provide information, the more it get easier to get fast into your solution.

Paul, first of all thanks a ton for going out of the way to help. And for that audio clip, I really want to thank you in person someday

Please find my inlined answers in bold.

I'll describe a bit in detail about average, please bear.

While coming back from Agra on 2nd October, bike was in reserve. Trip one was reset exactly when it came in reserve. I added 450 rs petrol once and later added 650 rs petrol more. That makes 1100 rs worth of petrol @68.46/litre (I love Delhi )

That makes 16.07 litres of petrol. Bike has done 532 kms on trip1 as of now. Still it is good for 100 kms more before it comes to reserve (Today came down to 4 bars from 5)
632/16.07 gives a healthy 39.32 kms/litre
I'm not ripping it off. It's just my bro who rode in God mode for 40 odd kms

As of now, I'm trying to avoid getting tensed about it because average is good, pick up is good and engine is as smooth as I would expect on SS Motul.
I just make it a point to check oil level daily when I reach office. Waiting for it to conclusively fall below lower mark.

Note: Updated 1st post with lots of data.

@ madhav, clarify one thing, is the black smoke only when engine is cold? And you also mentioned that spark plug color was silver in your earlier post.. So there can be a possibility of your bike's auto choke is malfunctioning. Bad auto choke is just my guess, because Your spark plug's saying engine is running lean. Ideal color is tan/brown.

Only once did I experience smoke in hot engine after a hard ride of 20 kms. Will post the spark plug pic during the weekend.

Important update:

Being a Friday, I thought of breaking the shackles. Decided to go for top speed. If anything went wrong, I thought I could have it taken care of on Saturday.

So on my way to office, on the Noida-Greater Noida expressway, I crouched and let the bike sing its song.

It easily went upto 143 on the speedo. Thats what I could see, I believe it reached 145 before I released throttle as I saw traffic coming up.

Reached office and saw that the engine level was still between the two lines. Have taken a pic of the oil level.

Buddy, your bike is in good condition. Don't worry much. Keep oil level under check all the time and keep on munching miles

I reached home today.

If de-carbonize has been done with water, then what kind of metal plate has been changed and resealed as u mentioned? Does your decarbozination has been done manually or not? i.e, opening a head and scrapping the carbon on the head with blade or paper. If yes done manually then why water is being used? Its still not been cleared to me if what method is actually used to decarbonize. Clear this to me.

On the other hand,
as per your description, your engine is good. The speed u mention 145 cannot be touched when the bore is worn out. and if its easily pulling on the upward direction as usual then make up your mind your bore is perfect.
I still cant see your spark plug picture.
All i can say, keep a track on your oil level.

BTW, what is the common top speed as said by the company or other P200 owners used to get?

P220/200NS top speed is around 136km/hr. P200's would be somewhere around 130.

Given the right conditions, both newer P220s and 200NS can breach 150+kmph. P220 carb from 2009-10 manage 145kmph. P220 Fi manages 136kmph. P200 (twin spark) does a top speed of 130kmph. Which one exactly do you need?

I don't need anything.. was just trying to answer the last sentence of Paul's query.

150 km/hr on a 200NS!! That's a nice finding please share with Bajaj, may be they would want to update their website which mentions 136km/hr
Pulsar 200ns Technical Specs, Pulsar 200 cc Specifications

And Pulsar 200NS and 220F has same top end as per this thread - http://www.xbhp.com/talkies/what-bik...ne-guys-3.html

I have touched 151 on this bike earlier (You may consider tailwind and downward slope, and a crouching position). But that is on speedometer. Manufacturers depict higher speeds on the speedo almost as a rule to overcome the speedo error. And it's 10% higher than actual meter reading. So you can say touching 145 km/h is actually around 130 kmph. 151 would actually be 135 odd.

I read it on wiki that manufacturers show higher speeds by 10% considering their meters would have max 10% error. I think that it is made mandatory by government so that no one is charged with speeding when the meter actually showed less speed.

Sorry paul1911, I'll upload it soon. I have never opened spark plugs on my own before. But this is a good chance to do it for the first time

As per decarbonising, it was performed similar to

Decarbonising IC Engine using Water - YouTube

i.e. pouring water after removing air filter.


BTW, bike travelled 644 kms on 16.07 litres giving me just above 40 kms per litre!

Man.. I know you don't need this info. I was only giving the TS all the info he needed in one place . Of course, there is a +7.3% speedo error on any Pulsar which has a speedo indicated top speed of >140 kmph .

Recently did 135Kmph on NS200, and am very sure that there was enough juice left to get it over 140kmph any time!!

even MG had got good figures over 140KMph and many people have got it.

This is not a good way for de-carbonizing. When using water the carbon particles get remain inside the head i think. and it may damage inside. There is no universal evidence to prove this, but i personally & many others here feels doing it manually is the best way.

Next time, get it manually done when u cover about 15000 kms.

I think the black smoke & black spots on your palm on high rev is something related with this water method.

Well, drive freely, don't worry.