homemade intake manifolds

I have been playing around at work doing some casting, working on my pattern-making, which i am not very good at. i am attempting to make replacement intake manifolds. My Honda's have a metal tube extending from the head with a short rubber hose connecting the carbs to the engine, and since i am very cheap i figured the same will work on a KZ. the first set will be to mount GPZ throttle bodies onto a stock KZ650, that is to say the inside diameter will taper from 35mm to 24mm. the picture is prototype #3, #1 and 2 were just not right. i will make another pattern tomorrow, the flange needs to be another 1/4 inch wider and the tube section needs to be bigger for the gpz tb's. tell me what you think, and if there is any pattern-makers out there i need all the advice i can get
left to right on the picture Stock GPZ 750, Stock KZ 650, mine

Let me know how it works!

I'm sick of the rubber boot intakes.

dont go all the way to 24mm. stay as big as you can get away with and port match it. im guessing 28-29mm is doable

wow those look pretty nice!

So what will you use to mount the carbs,to insure a tight seal?:huh:

The only problem I see is that heat will transfer better through Aluminum better than hard plastic or rubber.

This might cause vapor lock problems. Another thought is the vibration being transferred to the carbs may cause the jets to loosen and adjustments to change.

ok, version #5 or so is not going well today. inclusions in the pour up the wazoo, oh well just a prototype. also i am trying to bore the hole in the mill instead of on the lathe with a boring bar, my cutter comp was off and hole is off centered sizing is right but just a bit off.
for sealing either i will cut a gasket or groove the manifold for an o-ring.
i just figure if Honda did it on the CB750 for over a decade and the nighthawks for a long time after that, it can't be a bad idea. for mounting i am going to use reinforced hydraulic hose and hose clamps. picture is right out of the mold

Over the years I've made quite a few carb holders out of bearing block shells we throw away at work.

These are for a KZ400s2. The bolts go through right at the edge, but they are very solid on the motor.

I just mounted them with a piece of gasket material. I also created an internal sleeve with aluminum so the inside diameter would stay constant from the carb to head to prevent gas from accumulating there. However, I also did another 400 without the sleeve and it didn't make much difference. Both ways ran great.

Then we just went to a parts store and bought a radiator hose from some unkown car. They had them hanging and we just matched up the diameters. My buddy also made new boots from the carbs to the airbox. It's not pretty, but it's all rock solid with no cracks, and it only cost a bunch of hose clamps and some radiator hose.

Here are the dimensions of what I used. My point is, if you just put in a tapered sleeve, might these bearing shells work for you? If so I can send you some.

The shells actually have the tube on both sides of the flange and I cut one side off and the other side down to the right length.

I guess there may be a problem trying to seal the larger opening to the head, though. Just a thought.

F. Years ago I put a set of 29mm smoothbores on my SOHC 750 honda by means of aluminum spigots. they were, swamped, offset, sealed by dual orings at both ends, fitted w/vac. holes for synch. and located via set screws. because of the various convolutions, they were cast, not machined.... your' project is at least as complex. I would strongly advise that if your' going to spent the time/effort to invent said manifolds, that you link to carbs which are superior to those of the day. G