TOPIC:

oh boy.. that's about CAD $30 for 3 and that's one carb set... for the jets... There must be a cheaper way!....

Just have to search:
ebay: "Holley Carb Carburetor 1/4-32 GAS MAIN JETS KIT 50-109 YOU PICK SIZE 12 PACK" for example.
You're still going to need the 1/4X32 "Tap for these jets.
If you want "cheap" - "A 3/16" Pop-Rivet with a length of 1/8" brass-tube pressed into it. A "Mig" tip. (Common thread), a plastic "Drip Irrigation" plug drilled out with a 1/8" brass-tube insert.....etc.

Should have mentioned that in both "2 month" starts the shop temp. (where my bike is always stored), was about +5c.
Typically we exhaust the battery trying to get these engines started after sitting for long durations.
Previous to starting this topic I had done numerous "Test" starts after having the bike sit for 1 to 7 days. Easier starts then the 2 month intervals and less Choke manipulation - probably due to some fuel/air being sealed in a couple of cylinders. In these "short-term" starts the Choke behaved more as it always did, with a linear response.

Regarding the (valid) concern of scharf when threading: The 1/4X32 tap I received is a "second" tap ( look it up) To get the correct full diameter thread, the tap had to be run-in almost 3/4 of it's length. As such (mine) did not extend into the plunger-bore!!!!! For those that are tapping for their preference of jet this is a critical point to remember to avoid the tap point coming in contact with the side of the choke-plunger. Otherwise; CLOSE the plungers - stuff a small piece of tissue down the hole up to the side of the plunger, soak with a couple drops of oil (to trap scharf), tap and carefully remove tissue and scharf. Use a Q-Tip to remove anything that may remain.
"So easy, a Cave-Man can do it" !

Sounds good scotch. After all, it's just about blocking that whole a bit by threading it and screwing in a piece of brass.

To get the correct full diameter thread, the tap had to be run-in almost 3/4 of it's length. As such (mine) did not extend into the plunger-bore!!!!! For those that are tapping for their preference of jet this is a critical point to remember to avoid the tap point coming in contact with the side of the choke-plunger.

What I have been doing when refreshing some blind threads on the bike is I had a pair of taps - one regular as they come with a well tapered tip for easy start, and a second one with that tip ground off flat. After cleaning up the first few threads I'd use the flat one threading only just a bit deeper than the bolt that would go in there. To check the depth I use bamboo skewers from a dollar store, this way easily avoiding bottoming out and stripping or damaging anything.

Should have mentioned that in both "2 month" starts the shop temp. (where my bike is always stored), was about +5c

Same here, if anyone wonders. My bike sits outside so it never gets warmer than the outside temperatures. I had smooth start ups with this mod even below zero.

Maybe I missed this info.... From the list of the sizes of these Holley carb jets, being from 50 to 109, which size corresponds to the desired size 3/32" size?

The price for the Holley jets 12 pack is right!

The 14 x 32" tap, what is the actual tap size in metric, as I think these jets are metric, right?

Oh Boy !!
First, for those that don't know, taps come in 3 different styles. A start tap which has a long lead start thread 3-4 threads), a "second tap" which has about 1-1/2 threads reduced for starting and then the "bottoming tap" which has no start threads and is for tapping a blind hole. Machinists usually have all 3 styles in their tap sets. The average Joe usually buys a tap set from a local supplier and it will almost always be a start tap set unless specifically asked for as a second tap set or a bottoming tap set.

1/4" x 20 NC (National Course)
1/4" x 28 NF (National Fine)
1/4" x 32 NEF (National Extra Fine) not a common size by most but still a standard. Sometimes hard to find NEF taps due to limited requests and not normally stocked by suppliers.

Kawboy:

Oh Boy !!
First, for those that don't know, taps come in 3 different styles.

LOLOL You like to amuse yourself, don't you! haha I see that 3 tap styles principle hasn't changed since the 1980's then!! haha But there is something you are missing there kawboy (no pun intended lol). Some taps come with flat tips, some don't. And they don't have to be starter or bottom.

So it happened that the duplicates of each size I inherited came all in one style. Not the start style for sure, but by the looks all with very nice sharp threads till the end and with very nice conical tips! Cheaper to grind one flatter than buying a whole new set ending up with more of the same, right? Especially when they are metric and not widely available.

Example. This might be useful for anyone fighting with attaching the tank badges. Those threads for the tiny screws require a tap size 3 mm - 0.50. It's marked as size #39. Guess what - I found only one available at a local specialty store! No set - just one tap. And if you don't know, as far as I remember, these tiny taps come often with conical tips - not flat. So, I had to grind that down a bit because otherwise I'd be puncturing the poor tank with the pointy tip and I just had it sealed and painted! Job done!

In Europe, we actually had taps marked from 1 to 3. I think it was in Latin - I, II, III. I can't find that on the taps purchased in Canada, but I see the NC and NF. We also were writing months in Latin. If you're born on December 11, you'd mark 11, XII. I have no clue if that has changed, but I am just trying to point out that some things, including technical matters, are not as black and white.

I am just looking at taps I have here, made in Canada, and some marked NF are conical, some flat. Actually, I don't see even one marked NEF in the collection I have. And there are taps that don't have any markings like that. And repeating myself again, some identical looking taps come flat, some conical. I am not a machinist nor am I intending to become one, so I want be reading any books on taps and dies, lol And I'd argue that an average Joe like me, or rather Stan - don't call me Joe hahaha, might work sometimes with what they have thinking outside the box and improvising. So, in my case, having all the taps and none marked NEF, I am perfectly fine with grinding some to make them bottom friendly (no pun intended again). I am all the way for proper and good quality tools for the job, but unless threading some deep holes in thick steel, I'd say grinding a tap for refreshing some threads in aluminum, or even cutting some fine threaded new, is adequate measures for the job.

Now, regarding those two concerning questions:

- From the list of the sizes of these Holley carb jets, being from 50 to 109, which size corresponds to the desired hole size 3/32" size, or that mentioned earlier Mikuni 280?
- 1/4 x 32" tap, what is the actual correct corresponding tap size - in metric?

Here is a link to a bottom tap for ya - conical tip. That's why I grind mine flat when needed!

1/4 x 32 UNEF HSS Plug Bottom Tap