Topic Approved.

@RockRider: Generally engines do not need to be opened up that early, unless you have not serviced it regularly. My F2 is proof of it-45K kms.done since 2004, no engine issues till date.
However, I feel you can take a second opinion. I have a certain inkling as to whether the silencer cleaning may take care of the problem. That should not cost much. If that does not solve the problem, maybe you need to open up the engine for decarbonation. But be careful&do not get the engine opened up by any other than Honda Authorized personnel. All the best!

@R15Rocks: thanks for your reply.

yeah I dont want those guys to touch the factory assembled engine unless I feel I cant do away without it. The smoke is just one off observation that I did today in the morning. otherwise no recent incidents that I noticed.

I will test the bike in the evenin post how I felt about the decorbonation thingy.

I have never heard or witnessed decarbing the engine at 30k, untill and unless you had run your bike without any engine oil in it.

Sounds stupid !

Its not blue smoke its white, seems you have burnt your piston rings.

Have you changed engine oil at regular intervals? If yes, you do not need a decarb.

This is an interesting topic. I was having the very same discussion with a friend yesterday (last year!).

most (lazy) mechanics say that decarb is necessary only for 2-strokes. but my rtr-fi's manual specifies a cylinder head and piston decarb at 18k kms.

A lot of conflicting and differing opinions in this thread ...

Im adding mirch masala with my take.....

What I've heard that engines need a de-carbonization job every 20-30K kms, depending on your engine type. Carbon formation will take place inside the engine no matter what, even more if the fuel you are using has not been too good. A de-carb job, cleans up the engine and extends its engine life.

There are two ways of going with a de-carb, one is the older way that is opening the head and manually cleaning the carbon. The slightly newer way is to use a engine flush liquid which does the cleaning job. Which between the two is more effective is a matter of debate. But the important part is who does it, if not done properly a de-carb job can also result in things going horribly wrong.

Since there is carbon formation inside the engine, the effective volume available is slightly lesser than a stock engine, that only means that the compression ratio is maintained. Once the carbon is removed there will be slight loss in power with the drop in compression, so a de-carb job is usually followed by a valve lapping job too.

I had a Honda Dio, I got its head manually cleaned at 18K kms....the engine felt SO MUCH better after that.

I'd definitely recommend you going for it, but get it done only from someone who know what they are doing!

I will definitely back praful's statements. Ideally, carbon build up inside an engine depends on various factors. A few that lead to accelerated carbon build up are

1. Improper fuel or oil being used
2. Oil levels more than recommended mark
3. Certain additives
4. Engine loading etc.

As praful says, de-carbonisation better be done by someone who knows what he is doing. Modern day flushes, de-carb treatments (Bardahl has one for sure) ensure that moderate to medium carbon deposits are flushed without opening the engine. Many manufacturers set the frequency of de-carb in such a way that moderate deposits can be cleared off with flushes (in order to preserve a factory assembled engine). This in most cases is between 20K-25K kilometers.

This said, it is also true that 2-stroke engines require a frequent de-carb since the design itself is such that oil burns with fuel during each power stroke. The quantity of oil in petrol (if it is a pre-mix) or the oil pump settings dictate the frequency of de-carb.
In a four stroke engine, since the quantity of oil that burns with fuel is low/negligible (relative to 2 strokes), they may require relatively lesser de-carbs.

okay, got my bike back day before. I got the decarbonation by liquid flush. Also my engine oil was flushed too. I see a marginal change in the feel, in terms of smoothness. But I am guessing it is also due to fixing of few body vibes. In the morning I still smell the smoke but I it isnt visible now.

@psycho_98: I do rip my bike but not to extreemes. Do you still think there is a possibility of piston ring bein burnt.

Check your compression ratio first that will tell you whether your piston rings are burnt or not.

^^^ can you elaborate on it? Dint get what you are trying to say.

Smokes from 4 stroke engine, even though it is small, bike's oil seal need to be replaced.

Joke!!

Guess the service advisor @ bajaj service centre told me decarb job @5k km for my p180