Announcement

**RaajD** · 07-24-2013, 09:43 PM

Re: Hero Honda Karizma ZMR

Finally!! After a mail to the corporate honchos and a bamboo-bashing as an after-effect to the dealership, my ZMR is finally running normal.

The piston-slapping issue was finally zeroed down to advanced timing and faulty fuel injection, something that I pointed to on the very second day to the ASC. They had earlier said that the timing cannot be adjusted. I had repeatedly contested that, but after the lengthy discussion with an official from Hero hqrs, my ZMR was taken in for all possible tests. Yes, the timing can be mechanically adjusted!! I guess working on my Bullet 350 CI for years proved to be fruitful. The idle RPM earlier was around 1700 and after the adjustment, it has come down to around 1300.

AS told by the ASC, there was no damage to the cylinder or piston/ piston rings whatsoever; something that I cannot be sure of! I test-rode the bike and it's running better than ever. I just wish they work like this without waiting for the DANDA from above.

My heartfelt thanks to everyone for the support and push!!

**abhi7013** · 07-24-2013, 10:00 PM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

Guys, I might just be bringing up an interesting topic.. I have read so many folks confidently stating that our ZMR/ZMA engines are one of the most relaxed engines on road.. But I was wondering what prompts us to make that statement ?? Just a popular belief or it is backed by any substantial evidence ??

I just came across some very interesting performance findings which actually shocked me to an extent.. would ofcourse share my own findings.. but would like to hear from some of you guys first so that I can compare & be sure of the what I have found..

Guys, open up n lets discuss on this...it might just help many of us to learn something more abt our bike & to also understand further limitations so that we can ride safer....

One clue; if our ZMR engine is really so relaxed, can it then take up further performance mods ??? If not, then why !!

I would let you know my understanding once I come back from gym..

Well, I am under the belief that when a karizma and a p220 do the same speed (obviously not the speedo indicated one) the rpm of karizma is lower than the pulsar's. Meaning the pulsar has to work harder to maintain the same speed when compared to a karizma. Which then implies that ours is a bit relaxed.
Hope my understanding is correct?

Sent from my MT27i using Tapatalk 2

**anmol_1990** · 07-24-2013, 11:05 PM

Re: Hero Honda Karizma ZMR

There is no doubt about the Karizma's engine being most relaxed which is required for long tourings!

**Bibhudatta** · 07-24-2013, 11:28 PM

Re: Hero Honda Karizma ZMR

Originally posted by psr View Post

For a 223 cc it makes only 17 Bhp with a long stroke....the compression ratio is 9:1 and even when some newbies accelerate like no to-morrow, a seizure is unheard of....the bike is a good package overall....now I look forward to your findings...

Originally posted by abhi7013 View Post

Well, I am under the belief that when a karizma and a p220 do the same speed (obviously not the speedo indicated one) the rpm of karizma is lower than the pulsar's. Meaning the pulsar has to work harder to maintain the same speed when compared to a karizma. Which then implies that ours is a bit relaxed.
Hope my understanding is correct?

Alright..Here is my finding..I was just analyzing the reason behind yamaha providing an all aluminum cylinder in my R15 V2 & that led me to these observations...

One of the key factors which specifies the level/amount of mechanical stress on an engine is the "Mean Piston Speed", commonly called as MPS by performance analyzers.. According to them MPS is THE factor which confirms the extent to which an engine is stressed/strained & it is calculated with the formula below

MPS = 2* Stroke * RPM/60 mm/sec or 2* Stroke * RPM/60000 m/sec

MPS is nothing but the mean speed at which piston travels through the cylinder. More the MPS, the more is the friction between itself & the cylinder walls and therefore more & more mechanical stress on the engine.. It does not depend upon gear or power generated.. Instead it simply depends on the RPM at any stage & the stroke which is a constant..

For a stock engine performance max limit considered by the performance guru(s) is 20 m/s. Anything above 20 (with 25 being extreme) means the engine needs special parts like forged crank, peened rods with good bolts / aluminum rods,forged piston/aluminum piston, lighweight pistons to handle the stress.. else the engine would simply blow off...

That is the precise reason all the bikes come with a "red line rev limit" which is 8500 RPM for our ZMR. Pretty less when compared to other street fighters, ain't it !!!

Well, lets have a look at the mechanical stress level (MPS) in our ZMR engine at 8500 RPM...

RPM	Bore(mm)	Stroke(mm)	Stroke/Bore Ratio	Corrected Piston Speed	MPS	Stress Factor
8500	65.5	66.2	1.010687023	1.005329311	18.75666667	18.65723646

Does it now explain why the rev limit is red lined at such a low level ???

coz guys our engine is already touching the higher MPS limit & there is already too much of stress.. you do some performance mods, change the filter to K&N, replace ECU with an aftermarket one to increase rev limit, & at some point engine would go BOOOOMMM..

Contrary to the popular belief (read MYTH), ZMR engine is no way a relaxed one at higher RPMs.. Infact it is way too stressed.. The engine has such a long stroke that it is just not designed for sustained riding at higher revvs.. However on a bright side HM atleast has ensured that the engine parts are of quite superior quality so that they dont break under this pressure so easily.. It is a bike designed to be ridden at milder revvs for long hours & that is the precise reason the engine is marked as a tourer instead..

Now to make you all happy, guess which bike is the most stressed one in Indian market ??? our very nemesis Pulsar 220 !!! with an MPS close to 21 !! & with such low quality engine parts, no wonder why P220 breaks down in 3 years

& guess why 200 Duke engine is hailed as one of the best ?? at 8500 RPM the MPS is less than 14 !! add to that, it is actually a rebored 125 CC duke engine, but still such capability due to a very short stroke of 49 mm !!

Originally posted by rreneav1987 View Post

Addicted to gym??? :-) mee toooo..

Oh yeah, can't live without it..

**abhi7013** · 07-24-2013, 11:49 PM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

Alright..Here is my finding..I was just analyzing the reason behind yamaha providing an all aluminum cylinder in my R15 V2 & that led me to these observations...

One of the key factors which specifies the level/amount of mechanical stress on an engine is the "Mean Piston Speed", commonly called as MPS by performance analyzers.. According to them MPS is THE factor which confirms the extent to which an engine is stressed/strained & it is calculated with the formula below

MPS = 2* Stroke * RPM/60 mm/sec or 2* Stroke * RPM/6000 m/sec

MPS is nothing but the mean speed at which piston travels through the cylinder. More the MPS, the more is the friction between itself & the cylinder walls and therefore more & more mechanical stress on the engine.. It does not depend upon gear or power generated.. Instead it simply depends on the RPM at any stage & the stroke which is a constant..

For a stock engine performance max limit considered by the performance guru(s) is 20 m/s. Anything above 20 (with 25 being extreme) means the engine needs special parts like forged crank, peened rods with good bolts / aluminum rods,forged piston/aluminum piston, lighweight pistons to handle the stress.. else the engine would simply blow off...

That is the precise reason all the bikes come with a "red line rev limit" which is 8500 RPM for our ZMR. Pretty less when compared to other street fighters, ain't it !!!

Well, lets have a look at the mechanical stress level (MPS) in our ZMR engine at 8500 RPM...

RPM	Bore(mm)	Stroke(mm)	Stroke/Bore Ratio	Corrected Piston Speed	MPS	Stress Factor
8500	65.5	66.2	1.010687023	1.005329311	18.75666667	18.65723646

Does it now explain why the rev limit is red lined at such a low level ???

coz guys our engine is already touching the higher MPS limit & there is already too much of stress.. you do some performance mods, change the filter to K&N, replace ECU with an aftermarket one to increase rev limit, & at some point engine would go BOOOOMMM..

Contrary to the popular belief (read MYTH), ZMR engine is no way a relaxed one at higher RPMs.. Infact it is way too stressed.. The engine has such a long stroke that it is just not designed for sustained riding at higher revvs.. However on a bright side HM atleast has ensured that the engine parts are of quite superior quality so that they dont break under this pressure so easily.. It is a bike designed to be ridden at milder revvs for long hours & that is the precise reason the engine is marked as a tourer instead..

Now to make you all happy, guess which bike is the most stressed one in Indian market ??? our very nemesis Pulsar 220 !!! with an MPS close to 21 !! & with such low quality engine parts, no wonder why P220 breaks down in 3 years

& guess why 200 Duke engine is hailed as one of the best ?? at 8500 RPM the MPS is less than 14 !! add to that, it is actually a rebored 125 CC duke engine, but still such capability due to a very short stroke of 49 mm !!

Oh yeah, can't live without it..

Could you show the calculations in bit detail? And 60mm equals 6000m?? How?

Sent from my MT27i using Tapatalk 2

**Bibhudatta** · 07-24-2013, 11:56 PM

Re: Hero Honda Karizma ZMR

Originally posted by abhi7013 View Post

Could you show the calculations in bit detail? And 60mm equals 6000m?? How?

Sent from my MT27i using Tapatalk 2

60mm does not equal 6000m mate... but sorry i had also mistyped.. it is 60000 mm = 60 m.. i have corrected my above post..

**rreneav1987** · 07-25-2013, 12:25 AM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

Alright..Here is my finding..I was just analyzing the reason behind yamaha providing an all aluminum cylinder in my R15 V2 & that led me to these observations...

One of the key factors which specifies the level/amount of mechanical stress on an engine is the "Mean Piston Speed", commonly called as MPS by performance analyzers.. According to them MPS is THE factor which confirms the extent to which an engine is stressed/strained & it is calculated with the formula below

MPS = 2* Stroke * RPM/60 mm/sec or 2* Stroke * RPM/60000 m/sec

MPS is nothing but the mean speed at which piston travels through the cylinder. More the MPS, the more is the friction between itself & the cylinder walls and therefore more & more mechanical stress on the engine.. It does not depend upon gear or power generated.. Instead it simply depends on the RPM at any stage & the stroke which is a constant..

For a stock engine performance max limit considered by the performance guru(s) is 20 m/s. Anything above 20 (with 25 being extreme) means the engine needs special parts like forged crank, peened rods with good bolts / aluminum rods,forged piston/aluminum piston, lighweight pistons to handle the stress.. else the engine would simply blow off...

That is the precise reason all the bikes come with a "red line rev limit" which is 8500 RPM for our ZMR. Pretty less when compared to other street fighters, ain't it !!!

Well, lets have a look at the mechanical stress level (MPS) in our ZMR engine at 8500 RPM...

RPM	Bore(mm)	Stroke(mm)	Stroke/Bore Ratio	Corrected Piston Speed	MPS	Stress Factor
8500	65.5	66.2	1.010687023	1.005329311	18.75666667	18.65723646

Does it now explain why the rev limit is red lined at such a low level ???

coz guys our engine is already touching the higher MPS limit & there is already too much of stress.. you do some performance mods, change the filter to K&N, replace ECU with an aftermarket one to increase rev limit, & at some point engine would go BOOOOMMM..

Contrary to the popular belief (read MYTH), ZMR engine is no way a relaxed one at higher RPMs.. Infact it is way too stressed.. The engine has such a long stroke that it is just not designed for sustained riding at higher revvs.. However on a bright side HM atleast has ensured that the engine parts are of quite superior quality so that they dont break under this pressure so easily.. It is a bike designed to be ridden at milder revvs for long hours & that is the precise reason the engine is marked as a tourer instead..

Now to make you all happy, guess which bike is the most stressed one in Indian market ??? our very nemesis Pulsar 220 !!! with an MPS close to 21 !! & with such low quality engine parts, no wonder why P220 breaks down in 3 years

& guess why 200 Duke engine is hailed as one of the best ?? at 8500 RPM the MPS is less than 14 !! add to that, it is actually a rebored 125 CC duke engine, but still such capability due to a very short stroke of 49 mm !!

Oh yeah, can't live without it..

Observation seems fine.. but the engine feels relaxed even at 110 kmph though we are not hitting the red line..

Yeah.. me too.. I can't live without hitting the gym

The pain after gym is simply fantastic

**Divya Sharan** · 07-25-2013, 12:30 AM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

Well, lets have a look at the mechanical stress level (MPS) in our ZMR engine at 8500 RPM...

RPM	Bore(mm)	Stroke(mm)	Stroke/Bore Ratio	Corrected Piston Speed	MPS	Stress Factor
8500	65.5	66.2	1.010687023	1.005329311	18.75666667	18.65723646

Except this portion, your finding is right.

Our bike maxes out at 125ish speeds says that the engine is stressed already. The relaxed nature we talk about is attaining similar speeds to other bikes at a lower RPM as pointed by @abhi7013.

Red line for ZMR is somewhere around 8250 RPM.

Now, MPS = 2 * Stroke * RPM / 60000 m/s
[However, corrected Piston speed is a method to more accurately represent stress on an engine.]

Corrected Piston speed (CPS) is calculated as:
CPS = mean piston speed divided by the square root of the stroke/bore ratio

MPS = 2*66.2*8250/60000 m/s = 18.205 m/s.
CPS = 18.205/(square root of 1.010687) = 18.1084 (you got this one wrong)

Hence, our pistons are already getting mad at 18+ m/s, hence extracting more out of it is not possible without making structural changes to the engine. In short; this is already the best that this engine can produce, keeping the safe threshold limit in place.

------------------------
FYI

Classes of CPS in motor-sport :

low speed diesels
~8.5 m/s for marine and electric power generation applications

medium speed diesels
~11 m/s for trains or trucks

high speed diesel
~14 m/s for automobile engines

medium speed petrol
~16 m/s for automobile engines

high speed petrol
~20–25 m/s for sport automobile engines or motorcycles

competition
Some extreme examples are NASCAR Sprint Cup Series and Formula one engines with ~25 m/s and Top Fuel engines ~30 m/s

**Bibhudatta** · 07-25-2013, 01:03 AM

Re: Hero Honda Karizma ZMR

Originally posted by rreneav1987 View Post

Observation seems fine.. but the engine feels relaxed even at 110 kmph though we are not hitting the red line..

Yeah.. me too.. I can't live without hitting the gym

The pain after gym is simply fantastic

I think you didn't get my point.. am not talking about attaining an occasional top end or anything of that sort.. i just showed with facts & in a technical manner that there is already too much of mechanical stress inside the engine at higher RPM.. talking in a strictly techie way that is not good.. you still "feel" fine bcoz of the quality material used & due to the way engine has been tuned to withstand this level of pressure .. but a feeling like that does not mean the engine is relaxed in real.. i hope i explained it correctly ?

Originally posted by Divya Sharan View Post

Except this portion, your finding is right.

Our bike maxes out at 125ish speeds says that the engine is stressed already. The relaxed nature we talk about is attaining similar speeds to other bikes at a lower RPM as pointed by @abhi7013.

Red line for ZMR is somewhere around 8250 RPM.

Now, MPS = 2 * Stroke * RPM / 60000 m/s
[However, corrected Piston speed is a method to more accurately represent stress on an engine.]

Corrected Piston speed (CPS) is calculated as:
CPS = mean piston speed divided by the square root of the stroke/bore ratio

MPS = 2*66.2*8250/60000 m/s = 18.205 m/s.
CPS = 18.205/(square root of 1.010687) = 18.1084 (you got this one wrong)

Hence, our pistons are already getting mad at 18+ m/s, hence extracting more out of it is not possible without making structural changes to the engine. In short; this is already the best that this engine can produce, keeping the safe threshold limit in place.

------------------------

I dont think i got the calculation wrong.. & if i still did then MS Excel did

just that i used 8500 RPM instead of 8250.. that is why you got a relatively less value..
Yes, the other point is right.. this is the best ZMR engine can offer with design unchanged..
------------------

Anyways, i just thought of sharing this finding coz facts help us know the actual capability, limitations & make us cautious for any future action.. But many people dont enjoy facts coz it distances them from their beautiful world of myths & assumptions.. & there is always that emotional quotient ('oh am a fan' thing).. but may be i have grown with my age & experience; so i talk a bit differently...

All said n done, i too own a ZMR !!!

**Divya Sharan** · 07-25-2013, 01:11 AM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

All said n done, i too own a ZMR !!!

OT: Do u still have your R15?

**Bibhudatta** · 07-25-2013, 01:20 AM

Re: Hero Honda Karizma ZMR

Originally posted by Divya Sharan View Post

OT: Do u still have your R15?

Kind of 50-50..

coz i have sold it to my cousin actually.. so its still kinda mine, yet not

.. but am just so attached to my bikes that i still use "my"

**Divya Sharan** · 07-25-2013, 01:29 AM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

Kind of 50-50..

coz i have sold it to my cousin actually.. so its still kinda mine, yet not

.. but am just so attached to my bikes that i still use "my"

Darn! I've never ridden a V2. Wanted a ride. :'(

**siddharthsure** · 07-25-2013, 01:52 AM

Re: Hero Honda Karizma ZMR

Originally posted by Bibhudatta View Post

Kind of 50-50..

coz i have sold it to my cousin actually.. so its still kinda mine, yet not

.. but am just so attached to my bikes that i still use "my"

OT May I know what is the MPS of R15 ??? Just out of curiosity.

Thanks

Sent from my MT11i using xBhp Connect mobile app

**abhi7013** · 07-25-2013, 01:53 AM

Re: Hero Honda Karizma ZMR

So if a p220 has that much stress, can we say that karizma is still relaxed and stress free?

Sent from my MT27i using Tapatalk 2

**Bibhudatta** · 07-25-2013, 02:05 AM

Re: Hero Honda Karizma ZMR

Originally posted by siddharthsure View Post

OT May I know what is the MPS of R15 ??? Just out of curiosity.

Thanks

Sent from my MT11i using xBhp Connect mobile app

Close to 20.. but it still absorbs extremely high revving coz the engine is built that way to support it..

----consecutive posts auto-merged-----

Originally posted by Divya Sharan View Post

Darn! I've never ridden a V2. Wanted a ride. :'(

i wish i would have still been the actual owner of it; then i would have met you one fine weekend & would have given it to you..

am sure you would love riding a V2 any day.. but only on a highway & solo..

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