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After Market Bigvalve Head

vav_mugen524

vav_mugen524

Veteran
I noticed that the after market BIGVALVE HEAD head having the same diameter/circumference to a stockhead at the exaust side where our elbow connected or header., and even at intake side. I bought a 22/20 SPS bigvale head and i noticed they are the same in stock head exaust and intake. Im planning to port the exaust but i dont know how big to be removed. Please help me how to calculate how many mm to be removed at the exaust side. The FORMULA if you have. Im using 62mm block ang 28mm pe carb. Hoping your assistance and God bless!
 
ianghol

ianghol

Super Veteran
vav_mugen524 said:
I noticed that the after market BIGVALVE HEAD head having the same diameter/circumference to a stockhead at the exaust side where our elbow connected or header., and even at intake side. I bought a 22/20 SPS bigvale head and i noticed they are the same in stock head exaust and intake. Im planning to port the exaust but i dont know how big to be removed. Please help me how to calculate how many mm to be removed at the exaust side. The FORMULA if you have. Im using 62mm block ang 28mm pe carb. Hoping your assistance and God bless!
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lc135 sps head is oem yamaha lc 135 head modified the valve seat to fit 22/20 sps valves..this is why the exhaust and intake potrs is same with your cylinder head from your bike..hope this help;)
 
vav_mugen524

vav_mugen524

Veteran
How big to be removed or to be ported, the INTAKE and EXAUST. They only modified the valve seat for 22/20 valve. Do we need also to make bigger the exaust or intake? How to calculate the size?
 
ianghol

ianghol

Super Veteran
vav_mugen524 said:
How big to be removed or to be ported, the INTAKE and EXAUST. They only modified the valve seat for 22/20 valve. Do we need also to make bigger the exaust or intake? How to calculate the size?
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puhunan ng mga mekaniko yan kya d basta basta tinuturo bro..just try to search it in google maybe it would help..
 
NextLevelSaibot

NextLevelSaibot

New Member
ianghol said:
puhunan ng mga mekaniko yan kya d basta basta tinuturo bro..just try to search it in google maybe it would help..
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This statement is true. We share general info but we never divulge trade secrets. Why? Because we spend time researching and trial and error and then researching and then do more trial and error.

Porting is an art. Having the proper tools is just one piece of the equation. One other thing you'll notice with mechanics who are really good with porting, is that they don't base it on the size, but the shape of the port. You don't just make the intake/exhaust tract bigger and call it "porting". There are several things you need to consider.

How I learned to port? I used my own bikes and learned from experience.

Just my 2 cents...Ride safe!!!
 
Sniper 03

Sniper 03

Veteran
NextLevelSaibot said:
This statement is true. We share general info but we never divulge trade secrets. Why? Because we spend time researching and trial and error and then researching and then do more trial and error.

Porting is an art. Having the proper tools is just one piece of the equation. One other thing you'll notice with mechanics who are really good with porting, is that they don't base it on the size, but the shape of the port. You don't just make the intake/exhaust tract bigger and call it "porting". There are several things you need to consider.

How I learned to port? I used my own bikes and learned from experience.

Just my 2 cents...Ride safe!!!
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Yes we all understand that. But we are not the competitors here! We are brother here @ t135, so why dont you share your knowledge to help others? Para naman po pag nag pagawa kami sa mechanic alam namin ang gagawin sa motor namin at naiintindihan. Para iwas loko sa ibang mekaniko. Pls tnx.. God bless and ride safe to all!
 
ianghol

ianghol

Super Veteran
Sniper 03 said:
Yes we all understand that. But we are not the competitors here! We are brother here @ t135, so why dont you share your knowledge to help others? Para naman po pag nag pagawa kami sa mechanic alam namin ang gagawin sa motor namin at naiintindihan. Para iwas loko sa ibang mekaniko. Pls tnx.. God bless and ride safe to all!
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toma we are brothers here in t135..
pero eto ang hanapbuhay ng iba satin dito sa t135..
kaya d nila masabi kung papano nila ginagawa(puhunan kung baga)..
parang art kac ang pag gawa..
iba ibang style..
iba ibang approach..
iba ibang paniniwala..
at..
iba ibang source kung panu ang pag gwa..
maybe u can pm them pero sakanila na yun kung sshare nila sayo kung panu gawin..

truth is..
aq nangopya lng ng gwa ng iba..
pero d q pwede share..
isa kac yung sa pinagkikitaan nya..
for personal use only kung baga:D:thumbsup:
ok nmn kunalabasan..
142 sa gps:thumbsup:
 
H

haen

Super Veteran
well.. share some basic :

intake port diameter 80 - 83% of intake valve diameter
exhaust port diameter 83% exhaust valve diameter (calc first equivalen size for the two valves into one valve)

while porting :
avoid sudden turns, think airflow as water, which don't like abrupt change in flow
under seating try to get 110%
choke area around 80% intake diameter
general rule.. 'LINE OF SIGHT PORTING', make it so the intake valve can be seen from intake

general rule of exhaust : floor are may be raised, ceiling reshaped
 
NextLevelSaibot

NextLevelSaibot

New Member
ianghol said:
toma we are brothers here in t135..
pero eto ang hanapbuhay ng iba satin dito sa t135..
kaya d nila masabi kung papano nila ginagawa(puhunan kung baga)..
parang art kac ang pag gawa..
iba ibang style..
iba ibang approach..
iba ibang paniniwala..
at..
iba ibang source kung panu ang pag gwa..
maybe u can pm them pero sakanila na yun kung sshare nila sayo kung panu gawin..

truth is..
aq nangopya lng ng gwa ng iba..
pero d q pwede share..
isa kac yung sa pinagkikitaan nya..
for personal use only kung baga:D:thumbsup:
ok nmn kunalabasan..
142 sa gps:thumbsup:
Click to expand...
Very well said, Sir ianghol!

I understand that being a member of this thread comes camaraderie, friendship and "tropahan" in every sense of the word. But as Sir ianghol said, some of us use it to earn money so we don't need to divulge everything. It's hard to come by a good, to be trusted mechanic but if you do find one, stick with him. It's hard to have too many mechanics fixing your bike. As Sir ianghol said, we all have our own way of doing things and how I approach setup and modification will be different from the next mechanic. The basics are the same but when it comes to modifying a bike for more power, we have different approaches.

Sorry if I don't post everything here. I still have secrets that I don't want to just share to anyone.

Peace out!
 
NextLevelSaibot

NextLevelSaibot

New Member
Just to add some more info about porting:

Don't focus on the intake tract too much. About 90% of the gains you get from porting is with modifying the "bowl", the area around the valve guide top to bottom, side to side.

Also, blend the valve seat to the rest of the area inside it.

Just my 2 cents!
 
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