Professional porting

I know how to port match manifolds, smoothing, and seat blending. Does anyone have photos or descriptions of more involved porting on a KZ1000 head? I am looking for some real hard facts about what works for this particular head, not a bunch of theories. I am looking to maximize a street motor with the following combination: 1075cc, 10:1, 34mm carbs, stock valves, K410 cams. I would hope for increase across a broad rpm range. Or am I wasing my time to do more than "clean it up", blend the seats, and match the carb holders?

you might want to look at this article about variable length intake runners. My 96 ford minivan (3.8L 6) has a pair of runners for each jug with a butterfly valve at plenum chamber-runner interface. The performance difference is quite noticable with the system active as opposed ot usning one r the other set through the full RPM range.

Can't help you on the porting. Have never gone beyond removing the step between carb and manifold. This made a big difference in the 73 2002

-Duck

well ive got some pictures somewhere of a gpz/j head i did but cant find them:S so ill just type out one of my usual longass posts for ya! anyway use your new intake boots for guide to scribe outside of ports then gradually funnel ports getting gradually smaller as you go in towards bowl area.do not polish intake ports,leave them a little rough to keep air/fuel mixed up and do not go crazy removing material from intake ports this will only kill low-midrange power which is what you really need for a streetbike.on the exhuast side i like to make bottem of port kinda flat and concentrate on top of port since that is the natural area exhuast will concentrate when leaving combustion chamber.you will end up with something resembling a D laying on its back,use an old exhuast crush gasket as a guide to scribe around port keep the D shape slightly smaller then your scribed line to prevent reversion back into port from header.just clean up bowl area,dont try reshaping things.stocksize valves are fine for smaller motor no need for all that fancy stainless stuff,just good springs and shim under buckets to go with those big cams!:evil: if you can swing it id reccomend having combustion chambers,valve faces ,piston domes and chambers done in piston coat.oh yeah dont forget to clearance head for cams and a good valve job.

Wireman, that is about what I've done for porting so far. APE says shim on top is OK for these cams. Am I asking for problems with shim on top?

if APE says they are ok id go with that,but thats right on borderline to my way of thinking especially if you wind her to the stars.:evil:

Jay at A.P.E. knows what he is talking about-no doubt. He didn't get where he's at by not being one of the best. I will say that my brother-in-law was running cams about .400 lift(this was years ago) and spit out a shim and took a chunk out of the head. Never seen another one ever do that since. Bad luck? Probably, but for my money, I'd spend the extra little bit and use S.O.B. bucket set-up. Cheap insurance.

There are many hundreds of KZs running out there with our 410s and shim on top. And I have also seen stockers spit a shim.

There are two reasons for a shim getting out. The first is component separation, better known as valve float. The bucket moves away from the cam lobe and permits the shim to escape.

The other is what we call "tidily winking" the shim. With large lifts and certain ramp profiles, the lobe will contact the shim at it's outermost edge. This causes the shim to be pushed down into the radial groove in the bucket which causes the shim to raise up out of the bucket on the other side. As the lobe comes on around, it just slings the shim right out.

The 410s will not "tidily wink". With our VS900K springs, there will be no separation.

Jay

Post edited by: APE Jay, at: 2006/10/05 02:24

Alright.I just had to get into this one. You can take your shims and spit them right back into the head, and do away with the .008 clearances. This clearance is looking for trouble, do you want a shim to exit? Huh, do you wnt it to go? Alright then listen to me. It does'nt matter if you work for ape or whathoever. I gaurentee i rev my bike higher than all of you have ever done to get the most out of the motor. I run .004 and will never have that problem. Now lets talk porting. You take that head, you port the everlivn pss out of it. Open the ports so wide that the boots have 2mm to rest on. Flatten the floors, d the roofs, OPen the throats, feel with thou finger for smoothe transition. Fill with jb weld where it's shy. Make your exhaust ports huge. Make metal fall from the grinder like rain. And don't anyone come in here and tell me different, that low end torque will suffer and whatever else comes out of mouths with no teeth. Ime neverr lost torque in my life. These heads need to breethe and that's final. And that doesn't mean spending money on crap you can do without horng out to a silverback for so you can keep them in bis ness. I woudn't hit my nees for anyone unless i wnted to. Im not going to pay someone for nothing. And i won't listen to the talk ither. My bike can hang with them all and won't brake either. Its tough when its your job, and its all you got and such. But i got a backbone and its real. AS i dont work for nobody, i can tell you what works and dont have to worry. IM sick and tired of the propaganda around and around the mry go rob a bank so i can have what dreamers want me to spend on. I know. I've done it. And it's always worked. And my bike is fast. ANd it will ppullll and it wont quit, and neither will you. so i have to say my piece. Does this make sense? NO. come back now all...

Nads.com, the difference is that you are working on your bike, you know what it will withstand, how high you can twist it, and if it breaks you have to fix it, while APE does work for 100's (1000's) of people that they don't know, and they are going to be blamed/sued if anything goes wrong, so APE has to stay on the safe side of all issues.

I am the same way, I do stuff to my bikes that I don't tell anyone about, simply because I have the tools, equipment, facilities, spare parts, and experience to repair/replace anything I break, while others may only have a single bike and be working in their deiveway. So if mine blows up it don't cost me anything but my time, while if theirs blows up it may cost them considerably more $$$$ than they can afford.

While you are perfectly happy pushing the limits and walking on the wild side, it's not for everyone

APE is well known, and I don't think they have to look for business

Post edited by: wireman, at: 2006/10/05 21:27

Jay, thanks for the shim explaination. Now, are you willing to share some porting advice? I read where you commented these heads are restrictive. With my combination and goal of a hot street motor should I stay conservative or can I open it considerably without the bottom falling out. I've read a lot about porting and have been experimenting with porting since the 60's (made some better and some worse). I expected the conflicting advice given so far. I just don't want to reinvent the wheel. These are old motors and everything has probably ben tried at one time or another. I would like to be able to use a pro's past experience. Heck, it's only a motor head. It can be replaced if messed up. At my age I just don't want to waste a bunch of time I could be riding enjoying the fruits of my labors. I am guessing that the valve job is more important than the porting?

i didn't see where anyone mentioned the small valves?

increase the valve diameter, get some more flow. won't matter how big your cams are, or how much you hog the ports if you don't get some more valve area.

ask yourself this: do you wanna wind the engine out, make your power at high rpms? or do you wanna have a fun torque engine that has a broad flat power band?

you can do either, and a decent blend of both, just put some thought into it.

my .02 is that you clean up the ports a bit, match up to your carbs, have new guides and seals installed, and go with larger valves.

i also think your carbs are too big for a 1075, but that's my opinion.

--r

Post edited by: solomrus, at: 2006/10/05 12:00