Chainlube
Well-Known Member
You know a boost port does nothing for the intake flow other than change the sound, right?
Carby Reed Valve on stock Nt carb with billet intake
- Thread starter Rconce01
- Start date
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Deleted member 12676
Guest
I'm sorry chainlube but what you just said is so f***ing stupid it doesn't even deserve an explanation of how wrong you are, not an explanation of any sort because I'm sure you would butcher the explanation to fit your bazingo world version of things.
If all it does is change the sound then why do ALL high performance engines have them?
If all it does is change the sound then why do ALL high performance engines have them?
Karl Snarl
Well-Known Member
Actually it does help clear the cylinder on low rpms. It does help. At high rpms its not even noticed by the engine. Ive researched this a lot. Helps create better torque in turn better acceleration. The key is to have it slightly, like just a tiny bit higher than the transfers and angled 15-45 degrees, depends on how you want your motor.
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Deleted member 12676
Guest
this is the basic rule for ports: the bigger the time*area, the higher the powerband and the higher the peak power.
"Time" is the length of time of port opening.
"Area" is the size of the ports. Adding a boost port increases the area and so you feel the difference most at high RPM.
www.dragonfly75.com/moto/porting.html
"Time" is the length of time of port opening.
"Area" is the size of the ports. Adding a boost port increases the area and so you feel the difference most at high RPM.
www.dragonfly75.com/moto/porting.html
Karl Snarl
Well-Known Member
Depending on your blow down. The boost port mainly helps with clearing the cylinder on low rpms if the hieght of the tranfers are not raised. At high rpms the port is invisible to the engine. This is straight from the lords of 2 strokes. Now if you change your ports, yes its job changes too. Bit if you leave your ports at low end producing it will have almost no effect up high. The exhaust port and pipe is the biggest part of gaining rpm. The transfers unchanged will hinder high rpms. The roof is wrong and so is the height for high rpms stock. Try the boost port on a low end machine. You'll see the lord of the smokers got it nailed.
You dont hog out the boost port. Just a skinny line up the cylinder to about 1mm higher than the transfers with about 15 degree roof and its all low end power. High end is not effected.
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Deleted member 12676
Guest
This is why I rarely visit this forum - too many idiots with opinions that are totally wrong but they are willing to fight to the death to protect them.
I'm going to make notices from this forum as Spam so I don't have to be exposed to the idiot opinions here.
I'm going to make notices from this forum as Spam so I don't have to be exposed to the idiot opinions here.
Karl Snarl
Well-Known Member
Wow bro, kindergarten got ya down? The info comes straight from the sources you use. Lmfao. Try again. Really should lose that name calling. Makes you look like a child. Sorry you cant make it work, should try reading the sources you quoted for ever and a day. No wonder everyone fights with you, you go right to name calling an acting like a child instead of good ol adult debating. Oh well, some people just refuse to grow an learn.
Karl Snarl
Well-Known Member
Whats ever worse and now i feel bad, i used to defend you and your sources. Now you're saying your source is full of crap. I still believe in them though. Those books are still being reprinted today, and at a huge cost to the buyer. An all of the information is still relevant to our style engine kits. Man, why did i ever stick up for you if all you're gonna do is start crap and call names. Used to look up to you and all your hard work, now im not so sure.
Street Ryderz
Well-Known Member
More names to add to the wolf pack, LOL.
Street Ryderz
Well-Known Member
Now that reed intake valving has come into fashion, there will be a lot of “sixth
and seventh” porting done to various engines. There are two different approaches to
adding extra rear-cylinder ports in reed-valve engines: That chosen by Yamaha is simply
to carve a slot leading up from the intake port to link the port cavity with the cylinder
when the piston is down at the bottom of its stroke. This “sixth” port is not fed from the
crankcase; mixture moves up through it and into the cylinder due to the ramming action
of gas inertia in the intake manifold, and also because of the partial vacuum formed in the
cylinder by exhaust system dynamics. Yamaha places the top of this extra transfer ports
on a level with the four already found in their five-port engines, and the roof of the port is
angled upward very sharply - about 70-degrees, in fact. Apparently, such “tuning” as is
done with this kind of port is mostly a matter of varying its width, but not enough
experimental work has been done with it to provide us with any guidelines. The other
approach to this particular kind of transfer port is to cut windows in the rear of the piston
to permit part of the charge compressed in the crankcase to blow up into the intake port,
from where it is then able to escape through the boost port and into the cylinder. From
early reports, the effect of this modification is to improve very substantially an engine's
power range at some expense to peak power. This is, of course, precisely the effect to be
desired in a large-displacement scrambler or motocross engine, but hardly what one
would be looking for from a road racing engine. My own experience with reed valves is
still too limited to permit me any firm conclusions, and the potential benefits of the
porting they make possible, but I am inclined at present to believe that they fall
something short of being the answer to the two-stroke tuner's prayers. Indeed, it may be
that their principal contribution is to keep carburetion clean over a wider speed range than
is possible with piston-controlled intake porting. I very much doubt that reed valving
will ever equal the ordinary piston-controlled induction in terms of maximum horsepower
- though I recognize that reeds have their uses in engines intended for general, all purpose motorcycles.
and seventh” porting done to various engines. There are two different approaches to
adding extra rear-cylinder ports in reed-valve engines: That chosen by Yamaha is simply
to carve a slot leading up from the intake port to link the port cavity with the cylinder
when the piston is down at the bottom of its stroke. This “sixth” port is not fed from the
crankcase; mixture moves up through it and into the cylinder due to the ramming action
of gas inertia in the intake manifold, and also because of the partial vacuum formed in the
cylinder by exhaust system dynamics. Yamaha places the top of this extra transfer ports
on a level with the four already found in their five-port engines, and the roof of the port is
angled upward very sharply - about 70-degrees, in fact. Apparently, such “tuning” as is
done with this kind of port is mostly a matter of varying its width, but not enough
experimental work has been done with it to provide us with any guidelines. The other
approach to this particular kind of transfer port is to cut windows in the rear of the piston
to permit part of the charge compressed in the crankcase to blow up into the intake port,
from where it is then able to escape through the boost port and into the cylinder. From
early reports, the effect of this modification is to improve very substantially an engine's
power range at some expense to peak power. This is, of course, precisely the effect to be
desired in a large-displacement scrambler or motocross engine, but hardly what one
would be looking for from a road racing engine. My own experience with reed valves is
still too limited to permit me any firm conclusions, and the potential benefits of the
porting they make possible, but I am inclined at present to believe that they fall
something short of being the answer to the two-stroke tuner's prayers. Indeed, it may be
that their principal contribution is to keep carburetion clean over a wider speed range than
is possible with piston-controlled intake porting. I very much doubt that reed valving
will ever equal the ordinary piston-controlled induction in terms of maximum horsepower
- though I recognize that reeds have their uses in engines intended for general, all purpose motorcycles.
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