Rings and piston both come in three sizes.
1.standard size- original size as bore.(nothing will be mentioned)
2.1st oversize- 0.25 more than standard(0.25 will be mentioned on pack)
3. 2nd oversize- 0.5 more than standard(0.5 will be mentioned)
Similarly piston comes in three sizes. For fitting oversizes you have to bore out your bore.
Now for your problem there are two solutions:-
1. fit a new standard size ring and your oil consumption will stop.
2. Fit 1st oversize ring to existing bore and piston. This is the best procedure as it will give more compression than standard size ring.
Here is the procedure how to do it:-
1. Open the bore and piston and separate the rings from grooves.
2. Take the old piston,bore and new (0.25 size) rings to lathe.
3. Ask the lathe to grind the gaps of rings so that they fit inside old bore with required gaps. this process is well known to lathe guys.
The second process will give you a lot more compression and your oil will not decrease even after 2k km.
To give you an idea

This is my joy new bore kit from usha. The red nark shows the ring gap. You can ask the lathe guy to keep same gap.
But first after opening check the bore if it is worn. If it is worn then go for new bore kit or if you know a good boring guy then bore it to 0.25 size with USHA piston. Usha pistons are best and cost very high.
Most probably your problem will be solved by changing to new rings as your performance is good. Follow the second method and change all the rings to 0.25 size and fit by grinding the edges. After grinding just polish the ring edges by using a file and then by sand paper. google ring edge grinding and you will get an ides. This method i follow in my joy and it will not consume a single drop of oil in 2k km while new bore kit will consume a little amount.
See the advise to sarbanoxley and same applies to you.Change the required parts or you will be in more trouble in future and will spend a lot. If you continue to ride like this then after some time you will have to open complete engine instead of just bore piston.
Ok ride with new filter for two days then adjust the ratio. Valves are leaking can be known from mileage and performance. A leaking valve will cause compression leakage and will behave as the engine is running rich. No matter how much you adjust the air fuel mixture your bike will feel it is running rich and also your bike will struggle to cross 8k rpm and top speed will be low. Basically the symptoms will be engine struggling to pull under load.
A extreme in fifth gear will increase speed at the rate of 14 kph for every 1k rpm.At 5k rpm it goes at 65 kph and at 5.5k it goes at 72 kph and at 6k it goes at 78 kph.
Check the pressure in tyres. I keep 29 at front and 36 at rear.

Analogue speedo extreme i have touched till 128 kph and the digital model which has accurate speedo like zmr touches a comfortable 118 kph which is also actual speed(all know zmr speedo is accurate as tested by various mag and hunk/extreme uses same sensor and same dia wheel).
So the actual top speed is near 116 kph for extreme and 114 kph for hunk. Do not test top speed so soon. Wait for 5k kms as hero honda engines take long to free itself up.
Just change the air filter. Your bike will be running rich because of dirty filter.

need some guidance...

I have been running the bike on the stock bore since the last 120000+ kms. the problems are as below:-
lots of metallic hammering noise especially when the engine is cold.
excessive oil consumption - I need to top up every 500 kms.
white smoky exhaust.

during the last discussion, it believed that the bore was busted. but while doing KEEDAGIRI with the bike, i found a couple of things that just dont add up.
for example,
1) if i increase the top up interval to 250 kms, the noise almost stops.
2) the bike has been hitching between 2500 - 3500 rpm - the rpm range when i am in the mood of just pottering arround. its like an on off thing.. at 1500 - 2500 is absolutely normal. if i pull at constant gentle throttle, the engine does not behave strange. If i pull open the throttle a bit hard, the bike simply dies and at 2500, it starts again with a jerk... i believe this is due to carburettion rather that the engine playing games.
3) the bike pulls decently strong from 80 kmph all the way to 115.
4) spark plug has little soot / carbon

now of the above points, first and the 4 point is whats baffling me. Can anyone explain why things are not adding up?

i am pretty much confident that the bore is busted since i know how i have been abusing the bike but why arent all pointers pointing in the same direction...
want to know this just for the sake of knowledge.

My valves should be definitely leaking then. I ve tried with AFR screw fully closed, it still runs rich. Struggles to pull with a pillion. Mileage never above 40 kmpl.

No way man.
5K = 60 kmph.
Some others please share ur condition.

keep it up guys, extremly knowledgeble thread , hope Hero addresses these issues in there future lots.

I am more than 100% sure as every alternate day i take my extreme to work and i ride at 5-6k rpm always.If yours is showing 60 at 5k then you are losing 5 kph which translates to power loss. Can you tell me which model it is(month and year).
Hero has already addressed the issue.The batch from 2008-2010 came with valves problem. this was a problem from vendor end. Thanks for visiting the thread and if you find it informative then you are welcome.

a bump up

just a bump up

Ok i will give the solution but first let me find all the solutions to your problem then i will post. I will also ask my mechanic and will post.

Mine is Hunk, 2011 March.
Infact it has always been like that. It has become a habit for me to check the 5K-60 kmph mark to make sure I m in the top gear.
Also, gearing commander showed the same.

Hunk has short gearings compared to Xtreme which translates to low speed attained by each gear and hence has considerable low top speed on 5th gear. My 4.8K RPM takes my bike to 60 Kmph whereas Xtreme might get 65 kmph in same RPM.

IMO that's the case with both bikes.

I had posted regarding short gearing of Hunk, but that time most of our FM's came up with the info that both has the same gear ratio, the discussion didn't catch up further. Now it needs to be started again it seems.

And for my Hunk also does 60kmph @ 5k rpm.

Thanks Sibun, yes planning to fix it ASAP. Its heard that bad piston/ring can cause more vibes and damage the conn. rod/crank. is it right?

You stated you dont have blower - so you can take the filter out every 1K and just tap in on some hard surface and use your mouth .

wow thats some effort you put in this post .

Can you point me where i can get this USHA piston and rings ? if its available in chennai i can even go all the way to chennai to get it .

Thanks.

hey i didnt take note that you are from namma chennai - where you going to get it fixed ? you going for the usha piston+rings combo as well ?.

First open the bore and check if it requires change. If the bore is worn then buy a new bore kit from hero honda and change it. If bore is not worn and only the rings have more gap then buy 0.25 rings and just grind it. I have told to google it. This is the most common practice. Also i do not know that USHA makes bore kit for extreme. It makes for splendor/joy, boxer/caliber e.t.c. today i will ask my retailer friend regarding it and post.
However pistons and usha can be easily available. But you must buy original USHA and fakes are everywhere. Check the condition of bore and if rings will do the work then just buy usha rings. Else if you know a good boring guy then go for 0.25 piston and rings and bore the engine. Both of you can do the work by doing together, this will help both of you. Since satson is in chennai and if he knows a good workshop then both of you go there and do the work as it will benefit both.
Yes,satson you are right riding this way will cause the con-rod to develop play and thus will require complete over haul of engine.
Why USHA piston and rings?
First of all they Were OE suppliers when hero supplied japan parts.
second their pistons are made in honda foundry, japan and rings are from RIKEN corporation,japan.
third the piston have 11% silicon and are semi forged so they do not expand on heating thus can run tighter clearance.
How can you know original piston:-

Usha pistons come in Plastic packing and have to be broken to take out the piston.


The OE pistons have holograms.

To give you an idea about quality the left piston is of USHA and right is MAHLE. These are pictures of my joy piston.
Regarding availability you can easily get in chennai as if they have distributor in cuttack, then they must be having a distributor in chennai.
Here is the address for USHA dealers:-
Jai Motors Limited
Anna Salai, Chennai, Tamil Nadu
044 2852 2462 ‎

Here is there website. You can call there customer care:-
USHA Sewing Machine, Ceiling Fans, Home Kitchen Appliances, Kitchen Hobs - Usha International Ltd
Even they manufacture valves.
But first determine what needs to be changed. Will ring change suffice or boring or new bore is required.