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Old 11-03-2011, 10:35 PM   #89 (permalink)
Stick your neck out...
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Join Date: Jun 2011
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Update 009
Here we are at the halfway stage!

The inlet is working its way down to the carb, section by section, but its a slow tedious process. Each section has to be welded, then the internal bore cut for smooth flow and polished, before the next section can be welded.

It looks like a real Frankenstein part on the outside but the bore is quite smooth, better than the rough cast original. The bore is also about 2mm bigger, so it should flow as well.

The big question (as Jay pointed out) is how bad will the fuel drop-out be. All inlet ports have some degree of drop-out (where atomized fuel particles fall out of suspension) but most avoid “pooling” because the port runs “downhill” into the combustion chamber. My “drop-out” will be greater than most due to the large vertical climb and the cool port wall, which makes “pooling” a serious problem. One advantage that I have is the ability to test the port on the standard C90 and see how bad it is.

As an interesting “aside”, earlier in this thread Patrick mentioned the Honda CT90 trail version which I note has a similar carburettor location, although much less extreme

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