i have several extra jets and was thinking of drilling them out. has anybody done this?

 

Yup. It's easy. Look up some geometry basics first though.
pi(r squared) ~~~~which is the radius squared times 22/7ths~~ is the area of a circle. The brains here will correct me if I'm wrong.

My point is that when you do the math, you.ll see that enlarging the hole by just one thousandth of an inch will dramatically open the orifice. It may not appear that way to your eye, but you should then convert the increase to the mathmatical percentage of what the original hole is.

In other words, to increase a tiny holes area by 100%- you would not guess it was so by looking at it is all.

 

atf it.

or just spend a few bucks at mazdatrix and get some. otherwise what sterling said. if anything i'd go to mazdatrix and look at there sizes as a comparison.

 

I don't recommend drilling them out. Let me tell ya a little story. Back in the not-so-good-old-days I worked for a company that made pneumatic parts. One of our customers was complaining about the flow accuracy of our parts. Here some dolt from incoming QA decided to check geometric accuracy of our parts with none other then a drill bit. Yup, little scratches from the drill bit being inserted were enough to throw the parts out of tolerance.

 

should i open up the primaries or the secondaries. i am not worried about messing anything up. i will still have stock jets

 

You're not making watch parts! Just drill it with a brand new bit, nice a nd slow, with no pressure, yaddayadda.

It depends- are you going to mechanical secondaries? Then I would go with just the secondary jets.
If you're still running the vacuum secs, then I would do both.

 

dude, the damnest thing i've ever got was a carb drill kit. go to napa and ask to look at their tool and equipment catelog. look in th ewelding section and in it you will find a nice little thing at the bottom of one of the pages that is a hand drill/chuck and in the other end is about 12 or 15 bits ranging from 60 to 80( i think) in machinists sizes. i pulled out my trusty digital dial caliper and found the .032" or .8mm i needed which is a 80 jet for my idle on the dellorto i have. it's cool

 

Question Sterling: Then why did you enlarge the primary jets on my carb, when you also set it up for mechanical secondaries?
Not trying to sound offensive at all, I'm just wondering what you are saying here.
Can't you just buy larger jets instead of drilling them out?
-->see my title for disclaimer

 

ok i was wrong on the sizes, but here it is: carb jet drill tool

 

It depends on what your fuel consumption concerns are. I'm on mech seconds, and large jets everywhere, and I get 12-13 MPG. Also, if you go mech secs and do my AP mod, then I suggest larger fuel jets. I believe I suggest that in the write-up.
Joe, I don't remember if I did drill out your primaries, but I think I did. And the reason I think I did was because you mentioned that at a later date, you were going to try to do the AP mod. If I remember correctly, you did'nt seem too concerned about fuel consumption...But again, I may not remember correctly.

I do, however, remember that the carb rebuild I did for youwas for free, and so I find it ironic that you would be the one suggesting that people buy new jets instead of drilling them out themselves, thereby saving money.

How's that carb workin out for ya?