I disassembled the entire engine and found that there are two small holes on Left and right main crankcase and is covered/sealed using m-sealalso most of the threads are stripped.
Gears,clutch basket,bore, piston and head are good.
How much does a crankcase cost ?

You can easily fix that original crankcase at any good metal workshop on a lathe . They'll put in new inserts and make exact size threads like new and plug the holes and grind to finish too . Cost is low . Find from a mechanic who does engine work where he goes for the metalworking .

There are two big holes and some cracks in the main cases
How to fix cracks ??
(I will post a picture soon )

P.S -I also got a complete o-ring kit for just Rs.12.

Can you post photos of the crankcase and i will help you. And regarding engine rebuilding if you have any doubt then post it here i will help you and if possible i will give you my number and you can call me if you face any problem.
This thread is completely dead for past many days.
The chart that you have posted is of which bike. Although it is important but with experience i can tell without measuring what is the defect.
Can you please find the service manual of splendor/Joy/passion.
@pinaki- The oil that you have posted, where did you find that. I am using Shell Ax 7 Of 10W 40 grade for many oil changes and is best for my joy. It cost about Rs.280. It is semi synthetic. I don't like to use 10W 30 grade in this heat.
Shell Advance AX7 | India
I am planning to use the same for my extreme after finding it good for my joy.
However the best oil that i have used is Veedol super swift which is semi synthetic and of 10w 40 grade and next time i am going to use it for all my bikes- splendor/joy/pleasure and CBZ extreme.
I am ordering the same of one cartoon through my retailer friend. As far my experience goes veedol has the best quality as on their label you can see they have MA certification and all oils are API SM certified- currently the highest certified valve train wear for oil in indicate.They also mention oil oxidation stability,aged oil performance e.t.c rating.
Please use veedol super swift and see the difference.
The thing with veedol is that they make gear shifting super smooth than any other oil. In our car we use Mobil engine oil but gear oil is always veedol as they make gear very smooth. Even in my bikes when we use veedol oil the gear becomes super smooth.
Tide Water Oil Co. (India) Ltd. - Products
Regarding performance of super swift :-
I usually ride it for 3000 km in summer season without any noticeable degradation of oil and my running consist of daily 70 km of 70-80 kph running on NH. I have not used it in my extreme as it is only 6 months and under free servicing but i will use it this time as the Hero honda oil doesn't last for even 1000 km. In my joy it easily last for 3000-3500 km in peak summer and sometimes i get bored of the oil and change it without any performance degradation. Last summer i had gone to balasore a distance of 210 km on my joy with my friend and all the way we were at 70-80 kph two up and the engine didn't overheat. While returning he was bringing his apache 180 from balasore and we were returning at 100-110 kph with he leading on his apache and me following it on my Joy. I maintained this speed on my joy for about 30-40 km and you can gauge the performance of the oil and also my bike. At 11 years old and 2.7 lacs(at that time now-3.1 lacs) it maintained above 100 on speedo for 40 kms even without overheating although it is only a 100 cc bike. My friend was amazed by its performance.
So if you can find super swift use it and see the difference. Today i am ordering a crate for my bikes.

@pinaki - If you are using motul 3000 4t then it is the best oil. And regarding the oil you mentioned i will ask my retailer friend. But in summer season use 20W 40 grade and in winter use the above oil. And do not be so frustrated, give the splendor some 20,000 km and you will see there is lot of improvement. And if you want then come to bhubaneswar i will give you joy's new silencer and you can get better performance. Even you can ride your bike to BBSR and i can help you in better performance by servicing your bike by my mechanic. A 20W 40 oil will feel only sluggish in initial running but after 2-3 km it will feel OK and you cannot feel any difference.
And regarding my joy i have not seen any other 100 cc bike perform like it(off course RX100, Shogun and shaolin are not included). Even it can teach few 125 cc a few lessons about performance. And please wait for 20,000 km and at 20k km decarbonise the head and after that see the difference in your splendor. You will feel that it has gone a lot improvement in performance.

Thank You Sibun,no need to give your phone number as I don't want to disturb you.


How do you support/mount/place the engine while rebuilding it ?

It took me about 1/2hours to disassemble completely and 2hrs to re-asemeble it back for the first time .

Camshaft ,rocker,pins are "toast" (head needs some work and all new parts)

Piston is usha make 50 oversize,bore looks good but piston has vertical scratch marks.
Gears and crankshaft are in very good condition.
All bearings are good.
Clutch assembly is good.

Why did you tell me not to open the oil pump ?

Here are some of the pictures of an old used cd 100 engine without any pollution reduction technology,no air injection no nothing.



Washed each and every part with diesel and hot water.

Note the holes,one at bottom and another near the cylinder stud thread(covered with m-seal)










Did I install the rockers arms correctly ?
It looks wrong to me.








I couldn't find any thing better than a old wooden stool to place the engine.


The stator plate was damaged by the tensioner guide as the tensioner arm's bolt was loose.







Same here,I use 20w40 oil year round,feels little sluggish for 2-3mins till it warms up but it revs like crazy after warm-up.
My splendor's engine has become "free/smooth" now after more than 15,000kms.
When I de-carbed passion's Head and piston crown ,the engine became a lot smoother.

What kind of servicing ? Please let me know.

Firstly Shoeb'Jee , that is an awesum post .. reading it over and over .. and the pics are awesum too (using picasa now?) . No better way to understand the engine .
The engine looks like it's centrifugal filter is blocked by dirt , needs cleaning with petrol or other solvent (carb cleaner would work great) . Moreover there was much dirt inside .. probably the blocked oil-filter was impeding oil circulation at all . That would explain the damages ?
Those holes and other defects in the casing is repairable by any competent lathe guy . Remove m-seal with heat(blow-torch) and scraping. No serious defect in casing . Piston can be replaced with 1 oversize , no ? With a good cleaning , a few parts , a set of new gaskets I think you can get it running fine . This is THE original Honda cub/CT-90-trail bike engine, voted the best in the world ever . Please continue the autopsy with more pics ,we are all learning a lot from this . Thanks .

I finished re-assembling just now but I forgot to take any pictures.
I have replace all the oil o rings and gaskets,cleaned it thoroughly,inspected all the parts for service limit.
I will test the engine tomorrow.

Only top-end needs reconditioning and some parts are to be replaced(top-end only),holes got to be fixed but If a new LH crankcase is available then it will be better.
Also I fixed most of the threads today and replaced all the old bolts with new shining bolts .


I am using picasa to host the images,these are raw images(un-edited)

A small hole(Oil passage) which provides oil to head was blocked which caused the camshafts to run without any oil. .
I had to use a similar size jewelers screw driver to unblock it.
The camsaft was "Black and the remaining oil got baked and formed a very hard layer on the cam".



To get a better idea.

I have already ridden from Bhubaneswar to Kolkata once , but I was then in my early twenties . My best friend had just completed his MSc at Bhubaneswar university (staying at the hostel) and was coming back home here permanently and he was not ready to put his beloved CD100SS on the train , so I went there and we rode it back to Calcutta , taking turns at the handle . At 40+ now I don't even know if I can manage that now , but it surely is tempting me .
I have an RX-135 too , but it is stored now because the cylinder-piston is shot from a bad rebore job and Yamaha is asking unreasonable amounts for the parts or it's not available anymore . I am missing that light powerful torquey machine . My other 2-stroker is an old suzuki Max-100R which is running fine , but it hasn't got that much power like the RX . It's pick-up is great however , mileage is around 40 kmpl . Yes I am sorely lacking a good mechanic here , so I'm kinda decided to do as much of the maintenance work myself(which I enjoy) on the running bikes, in my spare time . That way at least I'll know what went wrong when something does . The damn mechanics here are either cheats or plain incompetent or mostly both . Whenever I've been to one , I have always come back with one more problems in addition to the original one .
Have you got the carb-cleaner spray ? It's very useful in such situations , you can just pump it in one end of a passage and it will clean and blow out at the other end , ensuring clear passage . That centrifugal filter has a oil pass-thru at the center , check that it is clear too . Replace the mesh filter (15Rs) .
You can resize the images to 480x360 or so before uploading to picasa web albums . That size is perfectly good for webpage posting here . That way you won't use up all the free space provided by picasa soon .

You guys really mean that ? That this engine will still continue to set-in and get smoother untill 20k kms ? Mine is just a bit above 10k now .
Yes , untill now no better oil found than the motul 3000 4T plus 20w40 for the harsh summer here . Yamalube SL 20w40 was as good , but it's got pricey now .

Need to get the foll. tools for a perfect overhaul.
1.Valve spring compressor.
2.Feeler gauge set(Metric).
3.Snap ring pliers.
Carb cleaner.(Which one ?)

Planning to change.
1. valves
2. big roller,small roller, push rod,rubber & spring, oil pump sprocket, and timing sprocket,rockers, tappet screw and nut,timing chain,guides.
3.Tappet cover bolt
4.New piston and rings and cylinder re-boring.

Is this engine more powerful than the current BS-4 engines ?

No this engine is not powerful than current engine. This engine is only 7 bhp and the Y2k engines are at 7.8 bhp.
To remove the confusion for all members i am posting the detail series of the engine series:-
1. Pre 2000 series- 7 bhp and with short silencer and no cat con and no secondary air injection.
2. after 2000 and pre 2006 model(y2k) - 7.8 bhp with longer silencer and no cat con. Only secondary air injection added. Splendor/Passion-7.8 bhp and 7.7 N-m torque, Joy- 7.8 bhp and 8.1 N-m torque.
3. After 2006 and pre 2010 models- Same as Y2K models but with Indian parts rather than Japanese parts in previous series. No change in engine.
4.BS-4 or after 2010 models(black silencer models)- Along with the y2k models only cat con is added to further control emissions. This is for splendor which is presently with old engines and the new Passion pro/splendor pro/CD deluxe/CD dawn comes with new engines.
Air injection in no way affects performance. It is a simple technology to inject fresh air from air filter to exhaust port to burn the unburnt gas in the exhaust. In no way it affects performance. Only cat con affects performance as it doesn't decrease power but it only reduces the low end torque.
The y2k engines had the best performance among all the series.
Rumor is that AVL Austria will develop new engines for splendor and passions which will be more powerful and vertical cylinder engine.You can mount the engine in- between stool legs to work on it.
@pinaki- Yes your engine will run more to get free. What i have found is that all hero Honda engines from 100 cc to 225 cc require longer time to run-in completely than any other manufacturer.If you would have noticed the shine and unicorn usually smoke at 50k mark but all hero Honda engines run for more than 1 lacs without smoking. So you can imagine the tight tolerance in new engines.
Regarding your RX 135 i can help you as my mechanic recently rebuilt a Rx 100 with the help of his friend who owns a lathe. The lathe is so much experienced that he installed a new sleeve of MAHLE and a Standard size piston and the performance was note worthy. Even without run-in the owner rode it for 100 kms at 70-80 kph without any problem and presently reporting a mileage of 50 k pl. If you will send the bore then i can help you.
@shoeb- I will help you with your crank case in my next post.

Thank You Sibun.

What makes the joy generate more torque than spld/passion ? camshaft design ?

Sibun,So how do you remove the valves ? Any easy trick ?

Can you list some more tips and tricks for beginners like me ?

Waiting for your reply.

I am looking for this kind of shift lever as my passion's lever has worn out.

Which bike's shift lever is cheap and best ?Shine's/pulsar's/discover's/platina's shift lever? Will it be a direct fit ?