Torque converters?

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Does anyone know anything about torque converters? I am wanting to know how to increase the stall on a torque converter out of a CB 750 A. I can fit one in my lathe to cut it apart, and do any machining, but am not sure what it is I need to do to it once I have it apart. I am wanting to make one that will not start pulling until around 1500 RPM instead of the 700-800 RPM they do now.
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[shinyribs]

Stall speed is all about the angle of the internal blades. I'm not sure which blades you move ( there's two opposing discs in there, both with blades- impeller and stator iirc), or if you have to move the pitch on both sets of blades. But I do know that it's a crapshoot on what the new stall speed with be. There's a guy here that used to go thru my convertors for the Olds. $75 to cut one open, clean it, new bearings and/or shims, welded shut and rebalanced. It was an extra $50 to adjust the stall. He was pretty familiar with convertors for GM trans, so he could adjust the stall pretty accurately. I had a 9'' convertor that was stalling around 3500 and we shot for 6000. Ended up with about 5700-5800.

Changing the pitch of the blades depends on how the convertor in question is constructed. Some hade individual blades brazed in to position on a main disc. Lots of labor to re-braze all that mess. Though they cant also just bent bent. One-piece solid steel discs with stamped out blades have to just be bent, obviously. I have no clue which way you move the blades to increase or decrease the engagement point, but logic tell me a more severe blade angle will lock up sooner, whereas a less severe blade angle will require more rpm to pressurize. That's just a stab on the dark,though.

Also, a certain diameter convertor can only achieve certain stall speeds without losing efficiency. Meaning, a 10+'' diameter convertor forced to stall at high rpm (4000+) is gonna have a lot of internal slippage. But a 8'' convertor can be made to stall at 6000+ and have little to no slippage at operating speed. This is based on Gm stuff, of course, so your particular convertor won't directly apply.

It's kind of a black magic to it. Many convertor manufacturers for racing applications will sell a full race convertor for about $1200. There's tons of data to supply to them when you place your order. Total weight, tire diameters/construction, final gearing, hp @ certain rpms, tq @ certain rpms, internal trans gear ratios, engine size/compression/full cam specs, cylinder head flow charts...and the list goes on. Even with all their experience and data they will adjust stall speed (usually) twice after initial purchase, for free, since even they can't nail it the first time.

If you want I can get you his number. Just shout at me.

Oh,yeah. There's a guy at the sohc4 forum that bracket races an A. I remember reading something about him playing with stall speeds. You might find some info there.