Trivia time!

[LRiddle]

I have a couple questions that have been rolling around in my brain that I don't seem to understand, and I'm sure someone here can answer pretty easily.

1. Why is it that reproduction carbs are so expensive? Almost $300 seems pretty high for such a simple device. By comparison, you can by a 4 barrel 650 cfm Holley for just a few dollars more. So what gives with the high price, especially since they aren't factory IH? I'm guessing supply and demand, but not sure.

2. I will readily admit I know very little about transmissions, gearing and such, so could someone explain to me how the PTO manages to spin in the same direction and at the same (engine) speed, no matter the gear and even in reverse. Probably a simple answer, but it's beyond me.

No rush, and no big deal, just somethings that have my curiosity running. Thanks.

[Urbish]

1. No idea on the carb price. I have often wondered that myself.

2. The PTO can do what it does because the input shaft from the engine passes all the way through the transmission back to the PTO shift collar. That way the PTO is doing whatever the engine is doing regardless of which gear the transmission is in.

[Scrivet]

To expand on the transmission a little bit more. The actual transmission gearing is powered from the input shaft as mentioned. Each gear (each one with a different size and ratio) meshes with the input shaft one at a time (hopefully) to select the speed that is transferred to the differential via a different route while the input shaft becomes an "output" shaft to run the PTO.

For the carb I would agree supply and demand. In all likely hood there's only one company actually making at least a couple components, like the bodies. Limited production runs, change over/set up for the special run all add up. Plus the simple fact that people will pay that amount. If you were selling carbs would you rather sell 10 for $50 or 1 for $500? All speculation on my part of course.

[John *.?-!.* cub owner]

I will expand a little more on Scrivet's statement about transmission. The input shaft (coming from clutch) passes all the way through the transmission turning the upper gears in the process. At the rear end of the shaft is a set of splines, and a pilot bushing. The pto shaft extends into that pilot bushing, and has a splined sleeve that slides over the input shaft splines to couple the pto shaft directly to the input shaft. This means there is no gearing to reduce or reverse the pto shaft speed. If you will go to the top left of the page Quick Links, and select PDF manuals, then go down to Service Manuals near the bottom, then to IH Cub Service Manuals, then to Transmission and Differential, and page 3 shows a cut a way of the transmission that may help.

[schmibm]

Carb question. Kinda supply and demand. More like volume discount though really. The fewer made the more expensive they are. What really makes me mad is spending $300 on a new carb because there wasn't time to straighten the flange and helicoil the inlet because we had to get our project to the 4H fair. Then when you turn the fuel on the first time, it drips fuel. Arg!!!!

Think about it like this. It cost me about $1800 to rebuild my 4 cylinder cub engine putting out 9 horse last winter. I have rebuild many small block Chevy engines. A V-8 putting out between 300 and 450 hp. Those have never cost more than about $1200. Its all about volume of the parts.