Can any one tell me how to do porting the right way. I have an 06 RCM that is bored to 138cc a 26mm carb and an iner roter. I just want a littel more more out of it.
How to do porting
stillplaysinmud
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Can any one tell me how to do porting the right way. I have an 06 RCM that is bored to 138cc a 26mm carb and an iner roter. I just want a littel more more out of it.
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Yea it takes experience and knowing what your doing and what will make it flow right. bigger isnt better! have some one who knows what theyre doing do it.
search porting and you will find 100's of post that might be usefull if you still want to do it.
search porting and you will find 100's of post that might be usefull if you still want to do it.
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3,864 Posts
A couple of the vendors offer porting.
Hey,
Ive just finished a diy porting job and am pretty happy with the results. Havent got the engine running yet tho so cant comment on performance. These chinese engines generally have pretty poor ports so theres about of room for improvement.
Heres a thread off another forum which is a pretty good guide line...
http://www.pocket-bike-racing.com.au/forum/showthread.php?t=6988
If your not competant with engines ide recomend you get a professional... make sure you know what your doing before yo go diving into it.
good luck
Ive just finished a diy porting job and am pretty happy with the results. Havent got the engine running yet tho so cant comment on performance. These chinese engines generally have pretty poor ports so theres about of room for improvement.
Heres a thread off another forum which is a pretty good guide line...
http://www.pocket-bike-racing.com.au/forum/showthread.php?t=6988
If your not competant with engines ide recomend you get a professional... make sure you know what your doing before yo go diving into it.
good luck
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ancient chinese secrete
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if you're gun hoe on doing it yourself head to your local library and read up so you can help understand the internals of a motor. I suggest reading
4 stroke performance tuning by a. graham bell
and when it comes to porting take your time, since you're starting out try to keep the speeds of the cutter below 6,000 rpm.
4 stroke performance tuning by a. graham bell
and when it comes to porting take your time, since you're starting out try to keep the speeds of the cutter below 6,000 rpm.
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And the chinese secret is:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=129663-353-400-4/55&lpage=none
http://www.lowes.com/lowes/lkn?action=productDetail&productId=129663-353-400-4/55&lpage=none
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I have all the tools and eveything to go with it about $478.00 to tell the true.I ve done porting before on my 50 and SDG 110. what i wanted to know is. Is it better to leave the valve guides in ports or cut them out? At the track here in vegas i ve asked 10 people and no one knows. Somebody on here has to know.
With the intake you want to grind flat the guide and the hump around it. Depending on how serious you are on the port job you can go all the way then weld it up (you will break thru) or play it safe and leave a little bump.
Exhaust you want to leave as much guide as possible, it helps transfer heat away from the valve. You also want to leave material around the guide to tranfer more ;-).
Remember bigger isnt always better... have a good read up of that link, awsome info
Exhaust you want to leave as much guide as possible, it helps transfer heat away from the valve. You also want to leave material around the guide to tranfer more ;-).
Remember bigger isnt always better... have a good read up of that link, awsome info
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cutting the guides out will flow MORE air with WORSE flow caracteristics, but leaving them in and shaping them will only cause a slight decrease in CFM but will have BETTER flow caracteristics.
Porting is not for faint of heart it is a art and if you don't have like 10 heads to practice on I suggest you just clean them up.
you will also need to chose the right carburetor and one thing most people over look the right length & design intake.
Once again I suggest you speak to some serious porting guys look for a decent price and go that way.
PS. there is a lot of power to be gained out of our motor like all things it comes down to how much money are you willing to spend.
you will also need to chose the right carburetor and one thing most people over look the right length & design intake.
Once again I suggest you speak to some serious porting guys look for a decent price and go that way.
PS. there is a lot of power to be gained out of our motor like all things it comes down to how much money are you willing to spend.
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Being echoed again, bigger isnt better. The most bang for the buck you will get will be in radius on the short side of the port ( the floor ) just before the valve seat. Again cutting the valve stems all the way out in some heads works, but as already said, most of the time you will increase cfm ( and not by much unless there is a huge block in the way ) but will induce turbulence. The best thing you can do is to boat tail the area, reduce it , but dont remove it completely.
I always say this and will repeat it a million times, you only see high lift once and low lift twice. Meaning the valve opens and closes at.100 , .200, .300 lifts twice vs being lifted to .700 once. If you improve your low lift #'s you will get more increase in velocity. This will be a better gain then most all out race ports that are so huge you lose velocity to gain mass amounts of cfm , which wont do anything unless you spin the motor to 30,000 rpm or have forced induction.
This is one topic I really like to discuss with people , because it is very misunderstood.
While I havent ported a bunch of these little heads, I have ported and flowed and worked on many many race motors over the years. I have worked for several race shops and did a stint with GM and DCX race divisions.
Porting is an absolute science and if you dont have a clue of what your going to do , then dont touch the ports. YOU WILL RUIN THEM.
Good luck and read , read and research before you make chips....
I always say this and will repeat it a million times, you only see high lift once and low lift twice. Meaning the valve opens and closes at.100 , .200, .300 lifts twice vs being lifted to .700 once. If you improve your low lift #'s you will get more increase in velocity. This will be a better gain then most all out race ports that are so huge you lose velocity to gain mass amounts of cfm , which wont do anything unless you spin the motor to 30,000 rpm or have forced induction.
This is one topic I really like to discuss with people , because it is very misunderstood.
While I havent ported a bunch of these little heads, I have ported and flowed and worked on many many race motors over the years. I have worked for several race shops and did a stint with GM and DCX race divisions.
Porting is an absolute science and if you dont have a clue of what your going to do , then dont touch the ports. YOU WILL RUIN THEM.
Good luck and read , read and research before you make chips....
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I just want to say thank you! And i will let you know how it turns out
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Who would be the best shop to send your head to for porting?
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This is stillplaysinmud posting from another name and so i would just like to give the results of my porting job and i would say it looks and performs fantastic ,it is faster and powerfull then befor,thanks agian for all the info and taking the the post information.
P.S. my tranny sucks balls on a fat lady....
P.S. my tranny sucks balls on a fat lady....
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