1&2..Connecting rod and bearings generally need replacement only if it has play and is making noise under load.
How to check the connecting rod for play ?
--> After the bore is removed,turn the crank so that it is at TDC.
Now with the con rod pointing straight towards you , pull and push the con-rod and there shouldn't be any play(ZERO).
Also check the lateral play by using a feeler gauge,it must have some play but within service limits.
Con-rod wears out normally at 1.2-1.5lac KMs. If it is under 70K kms and with no excess lateral con-rod play,you can safely use the old con-rod with new bore kit or re-boring but if it is over 80K Kms and using new bore kit then it is recommended to do a full overhaul including crank bearings and con-rod and its bearings.

(Whatever I have mentioned above depends upon the condition of the engine and is a very rough approximate)

If re-boring then ONLY USE genuine USHA Pistons. I and sibun had a good discussion on this topic of con-rods and re-boring.

3.Yes,it involves splitting of the crankcases to get the crank out and a lathe operator to install the new con-rod kit by removing and press the new crank pin.

Re-boring is a precision job and most of them do not calibrate their boring machines and it is very common to end up with a bore which has very less piston to bore clearance.I have seen two engines which were re-bored and the fit was very tight. After just 4k kms when I opened one because it was lacking performance I was shocked to see so less clearance and cylinder was severely glazed.(Chikna hogaya ) Luckily it was running on a Usha Piston.

Thanks for the nice explanation.
Where is that conversation on con-rods and re-boring??

Now i understood that lathe guy experience on hone a cylinder is also very vital.
BTW, do you know the clearance on the end of the rings of NEW bore kit?? Service limit is 0.5 mm, but what is actual? A minimum clearance we can have on rings?
If that is considered while re-boring, then would be fine?

Also how to change o-ring of clutch arm? Edited and added on previous post.

Loosen the clutch cable lock nuts and remove the cable. There is a small spring whose one end it stopped by a clutch cover tab,just turn the arm anti-clockwise and the spring should be free,if not try to move it with a small screw driver. Now just pull the arm and it should come out. Lubricate it and install new o-ring and you should be good to go !
No need to remove the clutch cover just follow the steps.

To check the ring end gap put the ring in the bore and push it inside the bore using the piston without rings. It should be less than or around 0.5mm. To remove the ring use a piston to push it out otherwise you may scratch the bore.

I already mentioned that 0.5mm. But if re-bored should how much gap should be there? Look that 0.5 mm is the maximum limit. But in actual it should be less than that. Thats what i was asking for!! A minimum clearance we can have on rings under safe condition!!

And yes my crank has also gone when at 70k, so that estimation is right.

Very good of you .
I have a habit of carefully observing other bikes on the street and I see here (in kolkata at least) 6 out of 10 , sometimes even 9 have some sort of oil leak on the engine . Either from head , bore packings , tappet hole covers , oil filler caps , clutch covers, kick pedal oil seal etc etc . Scooters with a radial starburst pattern of leaked engine oil on rear wheel is common . Bike engines fully covered with oil and adhering debris all over it so that you can't see any surface (or where the leak ever was) is so common too . And most apalling is none of the riders either know about it or never bother and run the bike around like this nonchalantly . I checked some pf my friend's in these condition and they've leaked half their oil already too , because they have never checked the level or even know how to . Aur toh aur - mechanics ( both local & ASCs ) don't bother about such obvious oil leaks while doing some other servicing on the bike .

Same thing here. 4-5 years older bike surely have some short of leaks.
Owner doesn't care or they doesn't even know they are numb not every owner is perfect. But what about Mechanics? They know about the problem, their work is to let the owner know about what to change and cost will incur. Their work is to tell them about the problem, rest is upon the owners if he wants to change something or not. But they didn't even bother ever. I think their motive is to give low cost repair to their customer. Which again leads to other problems in the future.
Get well soon!

Some kind of RTV like Anabond 666. The other one which also needs it is the timing chain cover bolt's washer. If these washer are not crushed(or new) then there is no need of using any sealant/RTV.
Get well soon and check the plug cap.

Found the service manual for Honda CG 125 and CG 150
honda cg 125 titan es-ks-cargo '00 a '02 - manual de taller - Download - 4shared

one is in Spanish & Portuguese, but the content on the pdf can be easily copied and paste it to the google translator.

I went back to 20w40 grade oil after 2100 KMs of A.S.S filled 10w30 oil. Bought Motul 3000 4T plus 20w40 for Rs.220/- and got the oil changed at a nearby work shop.


Have the following queries though:
1. Motul 3000 4T plus 20w40 is hard to find. The shop i found this had just one tin left. So next time i find it in stock, is it wise to buy, say 3 or 4 one litre cans and store it at home? Will it deteriorate over time if left in its original container?


2. The mechanic who changed the oil said its not required to clean the oil filter for every oil change. Is it true? Or did i commit a blunder by not insisting on an oil filter cleaning?

1. You may store sealed oil containers in a cool & dark corner indoors for 5 years . People have used oil twice as old without any deterioration noticed .
2. What oil filter ?
Splendor and like engines have a 1) coarse oil screen and 2) a centrifugal filter that is build into the engine and is to be cleaned once every 10000kms ( by removing the clutch side engine case ) . The oil screen can be replaced if you wish (costs Rs 15 or so) but not necessary . So basically no replaceable oil filters here per se . Many of these bikes spend their life without a oil-filter cleaning either too . i.e if you have never ever cleaned it - do it once , then forget about it for the next 20k kms . Keep to timely oil changes .

Thanks Pinaki-ji for replying to my queries in so much detail. Its so stupid of me not to have learnt even the basics about this beautiful bike i have owned for last 12 years and driven close to 50,000 kms!!


Could feel the effect of the change to 20w40 oil immediately. Today morning it was again very chilly here in Bangalore. Bike refused to start to the first kick, the way it did yesterday when it was on 10w30 oil. Ah, its then i understood the difference between 10 and 20 grade oils!!


The upside being, ride to office felt like riding on clouds (remembered the original HH Splendor TV ad with a smile) Butter smooth ride, where it used to be slightly harsh earlier, engine used to strain post 50kmph earlier. Now all that is gone


Thanks to all members here for opening my eyes to the benefits of reverting to 20w40 oil!!

Yes , with your bike tuned to the earlier oil and filled with 20w40 now it does take a extra kick or two in very cold mornings . After start-up , let the engine idle for a full minute by the watch before you ride off . This lets the oil circulate up and wet all the engine parts - before you put load on it . After warm-up , 20w40 is real nice . Remember that less engine harshness and noise means less friction = reduced wear too .
Next , lubricate the drive chain and adjust the slack to about 1.5inch in the middle of the bottom run . This will give you slick gearshifting and even smoother ride . Cheers .

After the oil change, i started seeing minor oil leak from under the engine oil section onto the floor. Took the bike couple of times back to the mechanic, each time he tightened the drain bolt. The amount of leak reduced but did not completely stop. Finally on the third visit, he used some old cloth threads, wound it around the nut and put it back. Now am hoping this solves the problem, even though i realise its only a workaround/jugaad.


From reading on net, i understand tightening the nut too much after an engine oil change can damage threads and induce leaks. Is this what has happened in my case? If so, can i live with the jugaad or look for a more permanent solution?

May be your thread have became damage, overnighting damage it. So most probably yes.
Mechanic is not going to do anything perfect other than jugaad.
So u need to open it yourself to inspect the thread. Buy a new washer and also apply gasket sealant on the washer and tight it. This will stop your leakage.
If thread have excessive damage, then u would have only two options to fix this....
1st) Oversizing the thread and installing a new oversize bolt. But this will make your hole lager by 2-3 mm more. and will also need to find new aluminum washer for that.
2nd) If u want to stay on the stock size thread, then it needs to the take to the lathe. Then they will first fill that hole with aluminum, then they will make a new standard size thread.

But for both of this, whole engine needs to be open. And after the work has been done, it is also very necessary to wash all the debris down before fitting everything back.

The sealant should be flexible even after application right to account for the temperature changes, expansion, etc due to running?
Since i have ten thumbs and not too sure about these things, should i take it to the A.S.S and ask those guys to fix it? Iam sure the local mechanic would do nothing of this sort.