How to properly drill carb jets?
So if I have a jet that's 0.076" I can just ream it to 0.085" and not use a drill at all? Is that something I could do in my garage or should I just perhaps take the jets to a machine shop?
You can probably remove .011 with the reamer but be damn careful. Brass is grabby **** and you can stick a reamer, although that small a reamer with that short length of engagement should be doable. Just use a good lube.
Again, you also need to account for the radius at the entrance and exit of a jet. If you drill out that out, you can have a jet with a bigger hole that flows LESS and you will go wild trying to sort it out.
In the late 1980's I was working with mechanical FI and alcohol. I was buying jets and nozzles that were said to be flowed. I was at the track and it was hot Hot HOT and the DA was so high the birds were wearing oxygen masks. Anyway, I increased the return jet .010 (on mechanical injection the jet, or pill is in the return line so a bigger jet is LEANER which is opposite of a carb but the principal is the same) and the car went slower. And the plugs looked like the engine was a bit more fat. I said W in TF is going on. Threw another .010 at it and it slowed down more. I said piss on it and went home. If I was so stupid I couldn't pull fuel out and my tuning was slowing the car, I should pack it in.
So I called a buddy and he hooked me up with a local guy who had a flow bench for fuel injection. I ran down there after work and I watched him flow all 20 of my pills. On 2 or 3 actually flowed as marked. The pills I was using that should have been leaner were in fact, flowing LESS than they should have because the company that made them had ZERO standards. All that junk went in the shitter and I order Kinsler nozzles and jets.
The moral of the story is drilling jets is a bad idea. BUT, you have to do what you have to do. Actions have consequences. Once you remove materiel it's near impossible to put it back.
