Does the original piston come with some kind of a piston crown coating like ceramic? If it does you will most probably be heading for disaster if you shave the piston crown.

I observed carefully today, and there is knocking in lower gears and at lower rpms, up to 4k. With acceleration, the kat kat noise (its an overall engine sound and not the particular sound). At higher rpms, the bike seems to do well.

And, Just now I opened the spark plug (changed to new one just 1000 kms back) and took some pictures. Tried to look into the plug hole, and and its black, but don't know how much black it is. The plug appears fine and I took some pictures.

Some would say its normal cause of the mixed colours, but from my past jetting experience id say it was running rich previously but recently started running lean.
I have a pic of my plug with the exact opposite reaction, lean first and rich later.

Does the original piston come with some kind of a piston crown coating like ceramic? If it does you will most probably be heading for disaster if you shave the piston crown.

Nope its clean.

I observed carefully today, and there is knocking in lower gears and at lower rpms, up to 4k. With acceleration, the kat kat noise (its an overall engine sound and not the particular sound). At higher rpms, the bike seems to do well.

And, Just now I opened the spark plug (changed to new one just 1000 kms back) and took some pictures. Tried to look into the plug hole, and and its black, but don't know how much black it is. The plug appears fine and I took some pictures.

Ashwin, the plug is just 1000-km old. Didn't change the AFR setting after this plug is installed. So, no question of running rich before and then lean.

Which bikes have pistons with ( ceramic or other ) coatings ? Any idea ?

Hi .
First things first .
You must have either the help of a mech or the ability to do it yourself in order to complete the conversion . If your mech says it can't be done , there must be a reason why he is saying it . In this case I think it might be that he doesn't know how to go about it . First you have to tell him about the things to be done .
Those will be --
1 - Get a 220's 1st oversize piston (1st oversize will have 25 punched on top ). I'm not sure about going for 2nd oversize piston since it might require more and complicated work than I've done .
2 . Re-bore the ZMA cyl to accommodate the piston .
3 . Piston rings to be inserted .
4 . Shaving off a bit of the piston's top is required since the P220 piston is curved . Will tell you details later .
5 . Have to fabricate an item out of brass .It has to be made from a brass rod . So a lathe where the mech has good contact is required . Will give details later .

6 . Have to shave the metal gasket to accommodate the increased piston size .
These are the things I can think of right now . Please contact the mech and ask him whether he can do these things .

While modding my ZMA I told my mech that the risk will be mine . I bought a 2nd hand cylinder and did the mod on it so that if anything goes wrong I could revert to the old status . Luckily I didn't face any problems .

Finally , read all disclaimers printed on all packaged articles and assume all of them are applicable to this mod !!

We can continue this discussion after getting a reply from you .

Good luck in your quest for a 235cc ZMA .

Update after a long time:

2. LED pilot lamps (~28, (2*3)*4+4) @ 300 INR/pair

Get a ceramic led set, way cheaper and way brighter. Costs 90/- for a pair.

4. again a new Speedo cable

Get this one "44830KRY960S" dont go for "44830KRY900S" cause the latter is longer and doesnt look good.

5. standing still in ON position and turning the handle-bar causes a cut-off and resets the meter at a particular position, unable to figure out whats the problem, is it hitting some wire or what... this thing causes a lot of trouble on turns when bike suddenly shuts down!

Repeated issue, many users have faced this. Remove fairing and recheck the wiring.

Update after a long time:LED pilot lamps (~28, (2*3)*4+4) @ 300 INR/pair

standing still in ON position and turning the handle-bar causes a cut-off and resets the meter at a particular position, unable to figure out whats the problem, is it hitting some wire or what... this thing causes a lot of trouble on turns when bike suddenly shuts down!

Get a ceramic led set, way cheaper and way brighter. Costs 90/- for a pair.
Where to find that now? Can it be fixed easily in place of pilot lamps?

Get this one "44830KRY960S" dont go for "44830KRY900S" cause the latter is longer and doesnt look good.
What is the difference? Is that available globally/easily?
Repeated issue, many users have faced this. Remove fairing and recheck the wiring.
Yeah will have to

So finally an update you getting 28 smd led ? Check ebay if i remember correctly 28 smd led are around 160/180 for a pair .

May be a wire touching body at that point . Fix it as early as you can to avoid any major issue .

May be a wire touching body at that point . Fix it as early as you can to avoid any major issue .

Hi just a question in general ...

When do I get my bike checked for the PUC certificate.

I got my bike in feb 2012. Till date I have done 8000+ kms ..

Hi just a question in general ...

When do I get my bike checked for the PUC certificate.

I got my bike in feb 2012. Till date I have done 8000+ kms ..