Problem, is it intake reversion?

what a nice picture.
yep on the smaller base circle camshafts or sink valves in after decking head nearly to JAPAN.


glad to hear the back pressure of a silencer helped make the torque curve more even for some of you guys.

there are tuning gains on the exhaust side. besides have you noticed the loudest bikes are NOT the fastest ones?

the big chain theory == every link matters and you are only strong as the weakest.

oh yeah I forgot to mention in response of that 1045 ...

we built this 1030 KZ motor here for a friend. stock yamaha XS 1100 pistons and a 92 cfm head .500/.480 cams 37.5/31 mm valves slider clutch trans work blah blah blah you know the pro set up. 400# bike

130# rider and we are talkin 9.30s'here at cordova track, on a cold day maybe high 20s'

call me sanford and sons but if it fits correctly ????

we laugh all the time at the yamaha powered kawasaki beating modern sportbikes and such.. cheers !! all around!!

heck I know a guy with a 1428 and cant get into the 9s' he asks advice and never follows it. cough sputter spin you name it everything but makin power and putting it to the ground.

trippivot wrote:

glad to hear the back pressure of a silencer helped make the torque curve more even for some of you guys.

My theory is, rather than producing back pressure, the comp baffle is actually responsible for maintaining velocity through the exhaust which helps with scavenging during low and mid RPM. My comp baffle is straight through 2.25ID. This is a fairly large pipe and it make a very smooth transition at the collector/meg junction. From 3 to 5K it makes a big difference compared to an open meg where exhaust velocity drops off in the megaphone immediatly after the collector.

The transition from collector into baffle is tapered better on the comp baffle compared to a more blunt entry on the street baffle. I was wanting to experiment with downsizing the thru hole on the performance baffel but make the entry transition more tapered to increase velocity at lower rpms and keep the mid and top power with less noise.

Anyone know of a source for "long cone" exhaust adapters? The usual automotive ones I find make the transition in too short a distance. Edit-I found Burns stainless sells long transitions.

I once knew a turbo guru that showed big power gains by using long transitions in his custom exhaust systems. He said the transitions "fooled" the exhaust into behaving like it was a larger pipe.

Old Man Rock wrote:

@ Mark1122... "2" baffle in my Kerker"

I purchased the 1.5" baffle for my Kerker for I was concerned with the loudness of the 2"... The 2.5" was rated for racing only, blow your friggin ear drums out.

Is the 2" too loud to talk with a passenger while driving?

OMR

here is the post with a pic of Davel's home made baffle.
mid way through page 2.

kzrider.com/index.php?option=com_kunena&...mit=20&limitstart=20

Exitpupil wrote:

The transition from collector into baffle is tapered better on the comp baffle compared to a more blunt entry on the street baffle. I was wanting to experiment with downsizing the thru hole on the performance baffel but make the entry transition more tapered to increase velocity at lower rpms and keep the mid and top power with less noise.

Anyone know of a source for "long cone" exhaust adapters? The usual automotive ones I find make the transition in too short a distance. Edit-I found Burns stainless sells long transitions.

I once knew a turbo guru that showed big power gains by using long transitions in his custom exhaust systems. He said the transitions "fooled" the exhaust into behaving like it was a larger pipe.

Try Burns Stainless www.burnsstainless.com/

They'll pretty much make you anything you want and their prices are fair IMO. I had good service from them as well.

babyELR wrote:

I'm no mechanical genius here, but I do have two observations for you.
Years ago when I used to drag race motorcycles, one of the guys I raced with ported many heads. He really believed in D shaped ports, and it worked for him. His best run with no nitrous was 8.20 with a '78 2 valve suzuki motor.
Second, I work on F-18 aircraft in the military. The intakes are D shaped. Guess there has to be something to it.

D shape is good and has been used for many years. On the intake side, combined with widening the floor, it can help pick up the flow by slowing the air over the SSR so it doesn't all try to shoot to the far side of the valve.

The floor at the apex of the SSR is a fast [sometimes fastest] part of the intake port. It depends on the upstream mechanical design. Pushrod pinch areas are problems on other types of engines.

On the exhaust side, the floor is slow to dead. You can raise the roof to give area where the flow wants to go and also raise the floor to take up the dead space for velocity gains.

Don't confuse the D shape itself with epoxy filling to obtain a specific CSA. They are not one in the same but are commonly used together.

A simple DIY test method would be to use your shop vac on the exhaust side to force air through the exhaust port. Use a thread on a simple wand to discover the dead and fast section of the port.

It's possible for an exhaust port to be breathing air back in on the bottom of the port while also exhausting air at the roof of the port.

Here's a Top Gas head that was on Ebay this week

Now thats 1 big port.i would have to think that it would produce very poor performance at low rpms,(low velocity)and screem up top(high volume).

trippivot wrote:

oh yeah I forgot to mention in response of that 1045 ...

we built this 1030 KZ motor here for a friend. stock yamaha XS 1100 pistons and a 92 cfm head .500/.480 cams 37.5/31 mm valves slider clutch trans work blah blah blah you know the pro set up. 400# bike

130# rider and we are talkin 9.30s'here at cordova track, on a cold day maybe high 20s'

call me sanford and sons but if it fits correctly ????

we laugh all the time at the yamaha powered kawasaki beating modern sportbikes and such.. cheers !! all around!!

heck I know a guy with a 1428 and cant get into the 9s' he asks advice and never follows it. cough sputter spin you name it everything but makin power and putting it to the ground.

That's an unique combination of parts. How much did you have to cut the pistons for valve relief?

mark1122 wrote:

Now thats 1 big port.i would have to think that it would produce very poor performance at low rpms,(low velocity)and screem up top(high volume).

There's no worry about low RPM for that application. It's a drag head. I think that particular one has 42mm intake valves. Notice the welded on spigots for really big carbs.....

i really need to learn to resize pictures!:blush: :laugh: trying to post pictures of one of the heads i ported many years ago for one of my 1170 motors.it came out better than the first couple aluminum doorstops i made on earler motors!:laugh:

Hey Plummen, sell them KZ door stops on e-bay. LOL!

Hell, those people will buy anything no matter how ridiculous or costly.

OMR