Dont touch it now,Do all other works and after that,see whether its doing good or not.

If you have seen all the damage for yourself and not going by then mechanic's words then the following things needs to be checked and replaced.
Valves
Valve guides (if damaged.)
Timing chain,tensioner and guides.
New bore-piston kit.(If the bore is worn out)
Inspect Rocker arms,rocker arm shaft and camshaft.
Inspect Timing chain sprockets (On camshaft and crankcase)
RE-seat the new valves so that they make a good seal.

If the con-rod play is out of specification then re-build the crankshaft along with new crank bearings.(For this engine needs to disassembled completely.)

Consumables- Head gasket,Head cover gaskets,O-ring kit,Crank case gasket.

If you plan to re-bore it-
Reboring,New piston and rings <1200
Crankshaft overhaul <1000
Valves,timing chain etc <1000
Labor <1400

So 5000 seems reasonable,although I am not sure. If you want peace of mind along with other items get a new bore-piston kit and it shall give her a new lease of life.

Other members like PSR,SIBUN,....... can give you more information.

Re: Karizma/Karizma R

Maxzma, never get tensed and leave the bike to a unfamiliar mech. Could have asked blore members help in my opinion, anways thats for your future. I would suggest that you along while buying spares. In normal circumstnces, you did nothing abnormal from your narration. But will need good understanding of what went wrong from the wearout.

Sent from my GT-P3100 using Tapatalk 2

Yes bro thats the plan!

There is very little play in the connecting rod. He says this could be the reason for the piston to hit the valve! But anyways have opened it till this extent so thought will change off those bearings as well. Got my camshaft, rocker arms and cam chain changed around 10-15k km back. But now he says the cam chain is worn and even that needs replacement.

True Sriram. Did not expect it to be this much. And I wanted to stay and watch what all is going in; so the nearby mech. Will make sure I go along when getting the spares. Thanks!

@maxzma- Your mechanic cannot determine what is the fault, so he is trying to change everything that is possible to clear problems.
The main problem in your bike is that your cam chain guide has worn out and also your tensioner. So when you revved the nuts off the bike in 2nd gear, the cam chain got loose and slipped on the cam sprocket. This caused the timing to mis match and valves hitting the pistons. So what you essentially need to do:-
1. Get new valves and rockers. Since valves are bent so new guide also.Change the guides at Lathe, polish the valves and seat.
2. New cam chain, new guide(both side), new tensioner, and new cam sprocket. If possible check the cam chain sprocket which is on the crank, but it wouldn't have worn as it doesn't wear so soon.
3. New 1st oversize piston. If possible get USHA- the best in market, but beware lots of fake. If USHA not available then MAHLE and then GOETZE. But please search for USHA, worth the pain.Bore the cylinder in boring machine and do it from reputed workshop.
Some of the dealers of usha piston rings in bangalore-

Vishnu Hydraulics Engineering
A 10, HMT Industrial Estate Jalahalli Bangalore

The Rubber House
# 3/1 Muneshwara Industrial Estate Tumkur Road Bangalore

Vishnu Hydraulics Engineering
Plot No 17 I 1 C Main Road 2nd Phase Bangalore

South India Auto Engineering Works
No 50 Bangalore

South India Auto Engineering Works
No 249 Sivan Chetty Garden Bangalore

AS Enterprises
No 93 Dodda Mavalli Bangalore

Sri Sai Tech
4, 8th Cross & 3rd Main Road Mohan Kumar Nagar Bangalore

Ganesh Engineering
Plot No 17/I, 1C Main Road 2nd Phase Bangalore

Nagendra Enterprises
No.1/3 1st Crs Kpm, Kalasipalyam Bangalore

So nothing to worry to get usha piston rings in bangalore.

Connecting rod- Nothing to worry as vertical cylinder engines do not need con rod replacement so early. They will run for 1.5 lacs or more before needing replacement. When con rod develops play then whole engine is overhauled and not partially.
The side play that you are describing is there even in new cranks otherwise crank will cease. Check for vertical play in con rod(up-down play). If no vertical play then nothing to worry. But i am more than 100% sure do not touch the con rod. Just do the top overhaul and your bike is ready to run like new.
Clutch plates- Why would it have any problem with this. Why did you let him touch the clutch plates. Did he opened it or just told you.
Cam shaft- if you have changed it then it doesn't gets worn out so soon. However check for any marks or wear on it physically. If there is wear then one side of lobes will have deep grooves on it.

Wow thats a lot of info and what all you had said forms up the puzzle.. Thanks a ton!! As you had said, the connecting rod only has a little play sideways. There is no vertical play. He opened up the clutch plates side to access the crank. But that was stopped there. So will make sure all the above are done. Will try my best for the USHA piston or we ll see what he suggests.

But bro I got the cam chain and tensioners changed only around 15k km back. How could it wear out so soon?

Off to the shop now. Hope there is some good progress today. Will keep you all posted.

Took the head to the lathe shop. The valves were bent indeed! He only is going to change the piston(the new piston will be around 0.5mm wider than the present one), rebore it, change the valves, oil seals for the them and set them all up. He told he will get this done in 3 hours. Please find the bill below. He has quoted Rs2540.

Will be going back in an hour. Will update again tonight..



@ACS(Arun): Hope I got your name right. I enquired with the lathe shop guy about the 220's piston here and he did not have an idea either. He told to stick with the stock one. Seems the 220's piston will be around 2mm wider than the zma's. Also, is the piston mod just a swap of the pistons? Any changes have to be made to the head or any other part? I am not going for this now but just for future reference. Thanks!

Awaiting your updates bro...

Regarding the 220 piston swap thingy, the answer is NO!
You need matching gudgeon shims for the con rod and add gaskets (if needed) to match the OE compression ratio.

I think you need a very capable mech for the same.

Update after switching over to Castrol Power 1 Racing FS Oil.

#The can was given from Castrol Themselves, not from any trader, so the genuinity need not be questioned here.

1.Bike feels sluggish after 5K-6K rpm. It takes ages to reach 100-110. But yeah the bike is smooth all through the range.
2.Heats up the engine faster compared to any of the Min/SS/FS i have used till date.
3.The problem occurs when you try to extract the low range torque of Zma. The same place where I used to ride uphill in 4th, is just not possible, have to shift to 3rd and accelerate.
Might be changing over back to SS if theis prolongs.

Bike stats:
Mileage : 54K kms
Clutch plates: Changed once, the present ones doing fine even now.
Sprockets: Still running on stock. I have a spare sprocket(original Rolon kit) set which i am waiting to swap for about 6 months now , but this damm thing is not giving up at all.
FE: around 35 which ever terrain,
Tyres: Front :ZApper FS 80-100-18 Rear : M45 4.00-18
Valve setting done in the previous service.

Lathe guys have no idea about these things - when I went to re-bore the cylinder they were reluctant to do it . They did it only because the mech was personally known to them and even so they gave me a warning ' we won't be responsible if anything goes wrong , what we do is as per your request and specification' . I said go ahead 'cause I had faith in my mech( I guess) and because I was willing to risk it . It is because the 220's piston is bigger that you get a bigger engine . Divya Sharan is right - the gudgeon pin in the ZMA is smaller (than required) for the gudgeon pin hole in the 220 piston . My mech had a washer made out of brass ( I think ) to match both and then there was a hole to drill on the brass thingy ( for oil circulation !?) which I did with a hand drill . There was no changes made to the head except for some 'fine tuning' to accommodate the additional load . The compression ratio changes because the piston of 220 is curved where as tho ZMA's is flat , co additional gaskets may be required . Also dents have to be made to accommodate valves ( which again was done by hand by shaving off the top of the piston ) .Basically , either the mech or you have to know what is to be done . Otherwise it is a hit or miss scenario . My mech had done it on other smaller cc bikes but it was a first for him on a ZMA . Since he was confident and I was willing to take the risk , we went ahead with it . Now , if anything goes wrong I can revert to 223 cc since I had done the mod on a 2nd hand cylinder and the original cylinder/piston is with me .

Thanks for the post!

Meanwhile, my bike is almost done. Have to mount the engine and fire her up. Hope all goes well. Will put up a detailed post tonight.

Just went through your posts...sorry to see the extent of damage in your bike...My thinking is that the timing chain tensioner had gone bad and chain became loose leading to severely altered cam rotation and valve timing, which lead to the Valves hitting the piston top......was the new timing chain and old one checked side by side or with scale to check if the old one had actually stretched ?...I am asking because you had done the job about 10~15 k kms back and the timing chain lasts for much more time.....if it is found stretched then the last replacement was with a sub standard one....When the timing chain went loose you must have heard the noise and recognized it immediately....since it had happened before and you know the sound...I guess the chain tensioner must have failed suddenly when you were driving ,and the damage happened on the run.
Do keep us posted..
Wishing you lots of good luck..
P.S. for timing chain and tensioner, buy spares only from HH outlet.

psr sir,how much life of tensioner and timing chain we can expect for our zma,my zma completed 48700 km,there is loss of power.while chnging 1st to 2nd gear small knocking takes place at low rpm could it be due to tensioner??tappet noise is not that much audible yet.carb air screw is at 4anticlock.my daily commute is 60km and it consistently deliver 40kmpl.

Did a 360 kms round trip between chennai and tirumala. The ride was fantastic. I am very much impressed with the way zma behaves on highways and hills. I loved the low end torque and the unstressed characteristic of the bike at high speeds. There is one thing I do learn for life from karizma. There can be performance without drama!!!

some ZMAs have run 75,000 Kms without problem , while some have developed problem in just 15~18 k kms. Basically an engine subjected to sudden acceleration, bad fuel, LONG OIL Change Interval(more than 2,500 kms)and poor maintenance,all lead to increased wear and early onset of problems.Judging by your FE the engine does seem to be in good condition..still it is better to check with a knowledgeable mechanic to find out if your engine actually requires any part to be changed.
From what you have posted, there are Two possibilities...
1. Air Leak through the AFR screw, which will lead to knocking at lower RPM
2. Timing chain slack leading to altered Valve timing leading to Knock.
Get both checked with a knowledgeable mech near you...at 48K+ kms ,there is a definite possibility of the tensioner+timing chain wear.