While searching the net.....

[gsxr400 racer]

I was researching some stuff on swapping a zx9 motor into my 1990 zx7 and ran across this site has a ton of good info and best of all pictures so if you ever wondered how most all build motors or check clearances have a look at this also this guy had modified his ports which is something I'm working on the bandit head...

http://homepage.ntlworld.com/webzxr/zxr750r/Features/sigvart_zxrr.html

[97af]

Great documentation.So how do you know if cutting the center section out of the intake track helps or hinders? Why wouldnt Kawasaki design that way to begin with if thats the way to go?

[Banditmax]

Cutting the centre section out is all to do with where you want the power to be made kawasaki will be more conservative with where they want their power to make the bike more ridable on the road.

[gsxr400 racer]

Velocity...ummm GOOD stuff more fuel if you can compress it and burn it big power. I think of it this way with the bandit it is a small motor that really runs better once on top, any help getting there is a real bonus...Maybe i should start a list of things ive tried...and others can add to it like the carbs with the longer intake track from the 750-600 dude...

[97af]

Lets here some suggestions...There's no time like the present!

[Chris H]

Forgive me but where duz it say he cut the middle section out of the inlet track?

[97af]

Forgive me but where duz it say he cut the middle section out of the inlet track?

Its not completely cut out,but I'm sure he gave his Dremel a pretty good work out.

[gsxr400 racer]

Velocity...ummm GOOD stuff ,big power.

[97af]

Velocity...ummm GOOD stuff ,big power.

Jay,I'm not so sure in this case even though there may be some performance gains.Opening up the diameter of anything decreases velocity.
If you push the same amount of water pressure through a garden hose then hook up a fire hose to the same source,its just gonna trickle out......

[gsxr400 racer]

no he filled them in... i think most ports on older stuff are to big

[Chris H]

I d'nt like his work!
He has filled part of the port in to make it smaller/increase air velocity, but he would get bigger gains by knife edgin the the point at which the port splits to feed the two inner parts.

[gsxr400 racer]

i hear you but tell me this why is the most arrow dynamic thing a raindrop why ar bird wing fronts not knife edged or airplane wing fronts... I think the knife edging is to be done on the exhaust where the air flow needs to come out of each port crisp.

[97af]

If he actually filled them in and decreased the port diameter,that would make sense but from the pictures,it looks like it is opened way up.I need to see two identical shots to see exactly what he did.One picture being off angle from the other doesnt do any good.

[Red01]

i hear you but tell me this why is the most arrow dynamic thing a raindrop why ar bird wing fronts not knife edged or airplane wing fronts... I think the knife edging is to be done on the exhaust where the air flow needs to come out of each port crisp.

Depends on what you wanna do with the aerodynamics... airplane wings are fat in the front and knife edged in the back because they are trying to get lift.  Raindrop shape comes from mass and gravity.  A knife edged split in the ports of a head would cause less turbulence... but that may or may not be a good thing.  It's not uncommon to design some tubulence in to help promote complete combustion... but that not usually something the average shade tree howler monkey can do in his garage.

[gsxr400 racer]

i hear you but tell me this why is the most arrow dynamic thing a raindrop why ar bird wing fronts not knife edged or airplane wing fronts... I think the knife edging is to be done on the exhaust where the air flow needs to come out of each port crisp.

Depends on what you wanna do with the aerodynamics... airplane wings are fat in the front and knife edged in the back because they are trying to get lift.  Raindrop shape comes from mass and gravity.  A knife edged split in the ports of a head would cause less turbulence... but that may or may not be a good thing.  It's not uncommon to design some turbulence in to help promote complete combustion... but that not usually something the average shade tree howler monkey can do in his garage.

less turbulence good for the exhaust (cause then you get into harmonics??I believe). Turbulence, swirl, velocity good for the intake well some kinds of turbulence