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Old 06-25-2016, 06:31 PM
Frankenstein Frankenstein is offline
Motorized Bicycle Newbie
Join Date: Jun 2016
Location: Allentown
Posts: 6
Default Oversized (80+) jets, where or how?

So, installed Reed valve, and other mods, had to increase my jet sizes a few times, latest mod involved needing more than size 80. Looked and looked, nobody sells them past 80 unless it's foolishly expensive (5-8 bucks PER jet) to buy it.

My method, use calipers to find a steel pin or needle of the appropriate diameter (79 jet is .79mm diameter hole. I like to press a micro drill bit of the Carbide variety against the pin perpendicularly with my fingers and turn the pin round and round untill a spiral groove is cut along the entire length, creating a pathway to remove material like a drill bit would, doesn't have to be deep, just noticeably there. The first 5-10mm from the point I rub a diamond grinding bit along it to rough it up a little, helps make it a bit more abrasive. Fasten the jet in a drill chuck one way or another, just not via the threads, a good way is to use a stock carb with the long brass rod that holds the jet. Run the drill, and slowly drive the pin in place.

Now you've got a custom sized jet. Works with any pin far as I can tell. Currently experimenting with drilling multiple micro holes in a closed jet, and adding up the surface areas of the holes to make a specific jet size. The multiple holes can atomize the fluid better than one large hole. Think about carbs with multiple jets per intake.

Whatcha think? Easier way to do this? It a bit of a pain to sort through jars of pins but the end result is always beautiful (and cheaper by a long, long shot.)

Also contemplating a way to stuff my crankcase with jb weld so that the chances of losing bits of epoxy being virtually eliminated. I'm looking as using some micro bits to cut holes, tap them to a 1.3mm thread, then locktight a few micro sized screws into said holes, and those will be the anchor to the jb weld, it would be next to impossible for the epoxy to fall off unless chiseled away. This method might not be for everyone, in fact it's not, you'll need a steady hand or a very small and precise drill pressing stand to make working threads. A little slop can be made up for with jb weld. Alternatively you can drill 2 small holes towards eachother at a 45 degree angle, and push pins into them, once jb weld cures around them they will be locked in place at the angle, locking the weld down too.

Mongoose terrex, stock engine ported, Reed valve, piston to match, delorto clone, modified shift kit, and a gastank from a 1970s suzuki ts125. My expansion chamber is cut and welded in my backyard, might be less effective than it was stock, but works well, looks fine, sounds like i chopped the baffle off, which is what I did, but around here everyone and their brothers car sounds like they took their muffler off so no biggy. Also bike gives me headaches as often as it doesn't.
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