| Below:
What I did to create the dual intakes
was to disconnect the two stock rubber intake boots from the air box/frame and rotate
them 90° out from the carbs...
(The white material you see on the intakes is a nylon fabric I used to keep debris out of the intakes while I waited to get the rest of the parts together.) |
|
Below: I then installed two 2-1/4" OD, 90° ABS plumbing elbows from Home Depot on the ends of the rubber intake tubes with the original clamps that held the boots to the frame. |
| Below: Next, I added the two K&N tapered filters with a 2-1/4" base, attached with the clamps that came on the filters. |
K&N part # RC-1250
| (There are other "Pod Filters" on the market that are much cheaper than the K&N, but the K&N filters come in the right diameter (57mm) to fit the elbows, and are superior in that they can be cleaned and re-oiled for a much longer useable life. In the end, even at the higher price, the K&N filters are by far the best buy.) |
| Below: Rain becomes a huge problem when you run this kind of intake system. The water can enter the filters and get through to the carburetors, causing all kinds of trouble. I was fortunate to get these two aluminum rain covers to solve the problem. (These rain covers were designed in 2003 by 'WidowMaker', a member in a forum I used to frequent. For some reason I cannot locate these covers for sale anywhere now). The addition of these rain covers required a 1/4" hole drilled through the center of the front cap of the filter. Installed in that is a 1/4" x 20 bolt, a 1/4" x20 nut, 2 washers and a 1/4" threaded chrome pike nut. In the image, you can just make out the bolt and pike nut installed on this filter. This is how the filter looks when you run without the rain cover. |
| Below: A couple of images of the intakes with the rain covers installed. The first with the cover oriented for use, the second with the opening out to show you how the filters can still get air when they are installed. |
| The rain covers are machined aluminum, polished on the outside surface. The inner surface remains unfinished. |
| Below;
Due to the fact that I can't find or afford larger
jets for these old Hitachi carbs, I have been learning the theory
behind creating my own jetting with the use of step drills and a second
set of stock jets. Until I am ready to take on the task, I have
restricted the new intakes to fool the engine into thinking it's still got
the stock intake system installed. To do this, I have added
what I call a 'restrictor plate' in each intake where the ABS elbow is
attached to the stock intake tube. The diameter of the holes in the
restrictors were made through trial and error, starting small and
working my way up to the present size where the carburetors run just a
bit richer than stock. This will do until I am ready for the task of
stepping the jets up to a size that will perform.
You may recognize the restrictor plates - made from the tops cut from Campbell's Soup cans! |
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