porting/polishing help

[440exnacsracer]

i know my sig says its ported, but thats what im doin this week, including the 450 and cam...im just gettin excited. for those expierienced porters/polishers though, how much can i take off the ports? i was guessin around 1mm would be good, maybe 2? thanks for anything. lata
Ben

[Sick0]

From whats I've read and look through. You will not get any gain from boring out the porst. A milded clean up, polish the exhaust ports is all thet you would really need. Any more then thats, you would might ruin you head, you quad wouldn't right and you atleat lose lowend. A radical port and polish if more for highly modifyed engines. Like 440 and bigger with all the goodies made to make more peak horse power.

[AndrewRRR]

I wouldn't do it unless you really know what you are doing. Porting can wake up your motor a little but can ruin it if done incorrectly. It's part rocket science, part art, and part voodoo (j/k). You can polish the exhaust if you like (dont polish the intake) and clean up the ports a little but I wouldn't suggest opening them up. Opening up the ports will allow more CFM to flow (assuming you make the path straighter than stock) but will result in reduced velocity which usually hurts bottom end. Usually people get oversized valves with porting, which is also something you can't do without proper equipment.
You can try it if you like but I'd suggest having a back-up head just in case!

[Maryland 400EX]

Ditto RRR... There is little to gain and a lot to lose for an inexperienced guy with porting tool. If you absolutely have to get it done, take the head to a high performance automotive or motorcycle shop to have it done by someone who ports heads on a regular basis.

[YZROOSTINYA]

why wouldn't you want to port the intake?

smoother path for air to travel?

[dariusld]

Go here for the answer to "why not polish the intake?". HERE (http://www.airflowdesign.com/articles/port_cylinder_head.html) Kinda of technical but you get the idea ... or not. If it was my head, I would go for it. I just wouldn't go crazy. I would concentrate on the polishing part.

[YZROOSTINYA]

OMG i was thinking the exact same thing as to NOT port the intake

kinda funny

[L.Vegas400]

here is a good site the explains it step by step. and they say to port the intake.
http://www.sa-motorsports.com/diyport.htm

[AndrewRRR]

You can PORT the intake (although I wouldn't do more than a little cleaning and port matching unless you know what you are doing). What you don't want to do is POLISH the intake. The intake port needs to be a little rough to cause enough turbulence to keep the air/fuel mix good and atomized. If you polish the intake to be smooth as glass it gives the mixture a chance to separate and pool the fuel. On occasion people polish the intake ports but its usually for extremely-high rpm motors that have huge intake velocities.
For me, with the cost of a new head in mind, I'd rather spend $200 and have someone who knows what will make it work and who has done them a million times before do it. But if I had a spare head lying around I might give it a shot. I have a spare 250r jug and head at my shop that I'm going to practice porting on. I've got a pretty decent idea of how to port 2 strokes, I feel. And if I screw up, who cares.

[Sparks425Ex]

Unless you are an engine builder do not do it. Engine builders have proven ways of Port/polishing heads. They are great at it. If you take off to much in diff places or leave to much you can kill your bototm end or your top end. There are so many diff ways to port and polish a head. You can do it for top middle and bottom end. Let the professionals do it.

[airheadedduner]

Hey AndrewRRR, have you read the book Two Stroke:Performance Tunning by A. Gram Bell?? I am also learning about porting so I could do some myself. It is an awesome book. Lots of excelent info. I bought it from Amazon.com for little over 30 bucks shipped. Also have you checked out [url]www.macdizzy.com ??Good stuff their too.

[AndrewRRR]

I haven't read that book yet but I've heard about it before, I'll have to pick it up.
Macdizzy has a ton of info, from basic to serious rocket science. It's a pretty cool site.

[airheadedduner]

That book is now my bible. It was difinatly worth the money, I take it everywhere with me. ****, I sleep with it:rolleyes: :eek: :blah After reading every chapter everything becomes so clear.

I KNOW WHAT A SQUISH BAND IS!!!!!! NUFF SAID:cool:

[440exnacsracer]

thanks for all the help and info. actually i am not porting the heads, i would only try it if i had like 3 extra heads! but anyway, my next door neighbor used to ride R's and he has a friend who does it. hes lookin for another R for a good deal, but he doesnt want like a race ready bike or nothin. lata
Ben