I think I got it!
Thanks Joel!
I understood porting (IF THE FOLLOWING Diagram is correct)

Same amt of fluid going in both pipes

Good man, that made perfect sense. Very good description. Keep it up.

Thanks!

Applying what i had learned was fun,

thank God what all I learned from book is not all useless (as most ppl say :P )

Many thanks to Joel & Omi - it made perfect sense & I've understood to some extend what this really means & how a simple polishing helps.
But wondering why the so called manufacturers don't do it? Is it such a costly affair?

I will have to completely understand porting to answer

But yea, factory setting are to achieve a target,

It will have to be a MIX, too much polished (glass ex by joel) too rough obstruction in flow...Like Joel said Porting it is wrongly interpreted..

and yes FE figures must be seeing a down after port modification,

besides power is not the sole purpose of ANY Indian manufacturer,
they give the best settings to Serve the purpose.

Joel can you post some pics to make everything more clear?

Lot of googling done

Conclusions

>Bigger Port Less power, bigger port makes it worse than stock
We want the mix to go with Velocity to gain power.

>One actually needs to REDUCE the size of intake port (at choke point) which is usually
65% of the Choke Point (where intake bends largely) and overall by near 30%

>Polishing is A big Myth, it will again result in loss of power,
to get velocity it Should be rough

Doing all this is DEFINITELY NOT a 1000rs job,
Its the Job of a Perfectionist, careful calibration and care has to be taken
Messing it all is the Easiest thing to do


Final Conclusion
If you want to do porting give it to Joel
Joel I am coming soon with my P220
Hail Google, Hail Motoman

@ omi- dude that was a nice presentation..and you did google a lot of stuff..kudos to you..but you forgot to notice that porting actually reduces the low end torque and increases the high end power..at low revs the bigger port does slow down the mixture but at higher revs, when the engine needs to throw out the gases real quick, the big port comes in handy thereby decreasing the low end torque and increasing the high end power..that's why people bore engines along with porting so as to maintain the low end torque..porting is not bad, it's just that to get something, you need to sacrifice something...you got a lot of points wrong there..if you reduce choke point, you will surely gain on acceleration but lose heavily on top end..polishing is not bad..the exhaust port needs to be as polished as possible for optimum gains..there again polishing helps reach greater revs..
correct me if i'm wrong joel..

Thanks about the fluid (though the diagram sucked)

About porting I have Zero experimental knowledge and what is posted is a
direct copy from Motoman (may have missed some points )
Yes i read that a bigger port will be good at high revs
But practically, even your ported Uni will be driven basically in city
The power band will shift, giving poor performance in city,

I am just concluding from what I read, Joel can tell the real stuff
being done all that, i am currently a theoretical guy


Joel can you please enlighten this subject a bit, looks like
the porting stuff (if done properly) can really get some nice power output
after reading motoman

A request to Joel: I really want to learn how basically a engine works,
can you suggest a book? I have just finished my boards and I have a lot of time in summers (after i give all bloody competitive exams)

Porting like I've said earlier is a vast subject.
So quotes like "large ports make low power", "motoman spec ports (smaller ones) make more power", "small ports give power gains" etc do not stand true always.
Port designs and flow characters differ from engine to engine.
A large port does not necessarily reduce low-end and vice versa. YOu need to be competent enough to understand what a given engine requires and then work on it. It comes with tons of tuning experience and after having experimented ports of various shapes and sizes. So please do not assume that smaller is better or vice versa.
Motoman methods were more applicable only on certain engine like the R6 in which he experimented coz the R6 lacks serious low-down poke. By making the port smaller, he gained a more linear power band and changed the torque curve, thats it. Do that on a CBR600 and that same motoman theory will backfire.
Tuning is not a subject that can be derived from books and concepts alone, you need tons of practical experience and it only comes with serious involvement in race tuning and with tons of dedication.
The top tuners in the world are not rank holders from a university, they are people with mammoth amount of practical experience. Trying to imitate is only a waste of time.

so basically what i can guess is:-

if a engine is stock and

1] has less stroke then making port smaller then stock will increase low end

2] has greater stroke then making ports larger then stock will improve topend

so bikes like unicorns etc will benefit from bigger valves\ports , short stroke like rtr160 may benefit form smaller ones

if engine is overbored then bigger ports will help a engine with greater stroke more then a smaller stroke one.

^absolutely wrong. I wonder how u summarised this up.
Read up all the posts again. The answers are all there.

@omi- if u are going in for engineering, you will know how an engine works in due time..like Joel said, somethings come best with experience..may be if u try porting and waste like some 100 odd cylinder heads, u may give him competition

hi

i have ported my uni's head & the initial is pathetic!!! but good with high revs

Can the size of ports be reduced by any chance?

I am using 60mm piston.

It's tough...Good aluminium welding is hard to be done.. You'll have to revert back to the stock head..