Looking at the pic it looks 'ok' but a real answer would lie in the service manual were they mention the correct ring gap and other values. that's why i asked earlier if you took any measurements to compare clearances.. but its always 'eye balling' measurements in hamara india
Did you see the marking 'us ha' on the piston or not - and you don't have to get scammed by your mechanic, even the spares guy could scam you or the spares guy might have been scammed by the distributor.. end of the day its you who ends up with the spares for actual usage. I am asking because sibun has pointed out that usha pistons come with the 'us ha' marking, and also the piston pic you posted looks very very similar to the one listed on sunbeams site so am JUST CURIOUS. and i guess SAL means sunbeam auto limited.
anyway now that the piston is inside, lets wait until it is removed again later on in future (hopefully not very soon).
sir ji, you can take all the time.. no hurry.

Sid, I got the piston in a sealed plastic container with USHA hologram (sealed means, its really sealed; you have to break the container to open the contents). You can see the pics of the container two pages back. If its a counterfeit, I can't help it, but to pray.

sealed hologram etc.. but after the major operation did you break a coconut and do puja ? if not do it asap.. its part of your 'praying'

Didn't do any puja. Now that you reminded about it, will do it.

Nothing to worry, that is original USHA pistons. Rest assured this will perform better than OE pistons.If you carefully notice then all engines are almost same. Check the engine in splendor thread and here all the engines are almost same. Bike engines are easy to work, the real difficult are to work on bajaj and LML scooters. Almost all engines are easier and more so in HERO bikes.From the ring gaps, i feel gap is slightly more, but in vertical engines it is okay. In Horizontal engines gap will be less. Also good that you came to know a lot ABOUT ENGINES.Looks like it is season of engine overhauling in XBHP as paul has overhauled his bikes engine, Krish his P220 and then You. Looks like next will be I as my Joy crank pin has worn down in the clutch side. Previously the same problem and this is because of these idiots lathe who do not set the crank pin properly. Since the clutch side of crank is loaded as the torque is fed by crank through clutch and the other side only works the magnet, so clutch side gets worn soon. The first time i opened the engine, the lathe guy who worked on the crank did an excellent work and crank ran again for 1.1 lac before opening, but the next lathe guy didn't did a great work and after 30k the crank showed the problem of pin wearing out clutch side. Again the crank was repaired and again after running for 35k the crank pin has worn down the clutch side. A normal guy cannot know the problem as it will make no con-rod sound and bike sound will be smooth while running, but while pulling bike will make crank noise.This is more dangerous than worn big end bearing as worn bearing will cause the con rod to develop play, but in this case, the one side of crank will vibrate on pulling and also chances of crank getting mis-alinged is there. Also it will wear the bore one side.So this time i will change the complete crank to new one as the lathe guy are hopeless and they have already damaged the crank enough in this three times that no further repair will be helpful. I will not clean the engine, as i change oil at 1500 km and my engine is as clean as a new engine, So i will just split the crank and put new crank and fit new piston and bore kit from USHA.Hopefully, i will open the engine next month.

Guys, can someone post the price of the clucth plates.
Tried checking the link provided by 'Divya Sharan' for the ZMA spares, but that link isnt accessible.

I purchased on this price Rs1425,new price is Rs 1485.

@ Ravi, The Credit for the entire sucessful completion of the job goes to You and the Mechanics and lathe work guys.
Regarding the Picture of your earlier Piston....there is a massive compression leak, and the piston had not run true, and had touched the Bore....Your old bore was definitely worn and beyond hope....
Regarding the small lines and pitting on the gears , I learned after extensive talk with some of my knowledgeable friends who rebuild engines, that a thin oil will cause the marks on gears, ...since the thin oil will not be able to form the required film on the moving parts thus allowing metal to metal harsh contact and backlash , leading to the marks.....
So I feel it is better to use a w40 grade than a w30 grade to safe guard the Gear box..

But as you will we replacing the bore along with the crank then why not run it till it develops play/bore gets damaged ? I mean if you were going to re-use the bore-piston then replacing the crank early would make sense but as you don't have the risk of damaging the bore why not use it for few thousand kms more ?

Are you planning to the bore and keeping it as a spare ?
Most of the lathes here don't have access to the hydraulic press and I have seen them hitting the pin with a heavy hammer to slide the crank-pin out and also to install it which is not the correct way.

After the pin is installed they don't care to check the gap between the two halves of the crank. They merely put it on the lathe and shave it off to true the halves which is again an incorrect way to do.

Here boring is done without any precise measurements.They bore it out and then slide the piston repeatedly to check if it is free to move. This results in either seizure due to very less clearance or burns oil and piston slaps due to excess clearance.One must be very lucky to get correct clearance.Till date I have never seen anybody use a "real" computerized boring machine for small bores.

Many parts which can be repaired are replaced unnecessarily just because of idiots doing these jobs. I am seeing that many lathes take up all kind of works but specialize in none.But there are some guys who show interest in work and will do the work correctly or won't take the job at-all.

Shirish, you sure about the link not working? I guess you were trying from office, where the external site may be blocked.
BTW, new clutch plates cost 1,480 bucks.

Thanks a ton for detailed explanation. Indeed I got to learn a lot about engines because of this overhaul, and yet there are so many minute things to learn which affect in a big way, like you pointed out above. As my bike's crank also was fixed on lathe, now I too doubt about the perfectness of the crank. I have all the normal measurements of the crank to check for, but feeling stupid that I didn't do that; I could have bought a calipers and check for those measurements. Of course, its a learning experience and not repeat this next time.

Regarding the piston ring gap, I too was a bit skeptical as I have expected a little more less gap. But, lets see how it goes.

And, all the best for the overhaul of your Joy.

I should have checked the compression before the overhaul, that would have given me some insights. Anyway, I will buy a gauge and keep it for myself. I would check the compression at around 500 kms and see how its doing. And does compression figures change because of rebore? and if so by how much?

And regarding the grade of the oil, I have used 10w30 oil only once and its the recent fill which ran for 1500 kms only. When my bike was with my friend, he might have used the 10w30 oil. I will not use any w30 oil in future.

I completely agree with you. The lathe workers here, unfortunately, would work exactly as you described. I tried to find a real CNC machine lathe worker but couldn't find one here. So, I had to go for this well-known lather worker, famous among the mechanic shops here. He gets to do at least 20 bores a day, numerous crank and valve lapping works.

Completed 2.3k kms on Super HDB Turbo, and still doing fine, planning on changing oil at 2.5k or sooner, depending on my free time.

And guys a while back had reported an issue with the self starter not responding at times. Now after using Kiney battery, the issue pops up frequently, its like if HL are on for a while then bike wont crank, only when we turn off HL bike will crank. So what I've come to understand is that, the ZMA has some kinda system which prevents starter from working when battery charge goes below X%.

Divya Sharan, yes i tried accessing it from office. That could be the reason for the link not to be working. Anyways thanks for the inputs.

NOT TRUE...You simply don't have enough juice to pull the relay and engage the starter motor...

Changed to Shell Rimula R3X for Rs.250/- , R4 wasnt available will take a week more for 1L stocks to arrive, costs Rs.360/-.

First Impression.


Thicker than the Super HDB Turbo, and gives way too much feedback, which can be abit irritating, other than that its all the same. Completed 50kms.