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timber0472
06-20-2017, 8:12 PM
Ok. Have an issue with carb spitting and a flat spot on free way.
Went down on my jets...70 to .66 on main and .295 on intermediate. Flat spot is still there. Spitting is gone though.
I have an old super e with the .40 air bleed hole. I started to drill it out to tap with a 5/16 but how far do you drill it out? Seems like I drilled too far? How far does that .40 hole go? I used a larger bit to open it up so I could get the tap in but it looks as tho the tiny hole disappeared. I only drilled about the depth of the jet that I bought. Maybe 1/4 inch down if that.
Any thoughts? Air jet size I purchased is a .58

farmall
06-21-2017, 3:43 PM
You just removed the restriction ("tiny hole") to replace its function with the jet. Tap your hole and install the jet. WD-40 is excellent for drilling, tapping and machining aluminum.

Blow out passages with compressed air and inspect using bright light.

timber0472
06-21-2017, 9:23 PM
You just removed the restriction ("tiny hole") to replace its function with the jet. Tap your hole and install the jet. WD-40 is excellent for drilling, tapping and machining aluminum.

Blow out passages with compressed air and inspect using bright light.

Ok but maybe I didn't drill deep enough. Shouldn't that hole lead or intersect another passage? Or at least lead somewhere? I am now left wth a 5/16 cavity or dimple. I thought this was an air passage way but I can't see where air could get through.

farmall
06-29-2017, 8:37 AM
Apologies for the late reply. It does intersect because of course a blind hole would serve no purpose. You probably figured that out by now but if needed I'll pull a bowl from my new in box spare and remove the jet to illustrate.

Blackbetty
06-29-2017, 10:53 AM
You need to drill until you break through - keep going. Per zippers from their thunderjet instructions:

5. Clamp Carb in vise upside down.
Locate original internal air bleed hole
(photo 5) to be blocked off. (’04 and
earlier) Carefully drill this passage with
a #21 (.159”) drill bit until you break
into cross passage in Carb body. Tap
hole with a 10-32 tap, blow passage
out with compressed air, then plug with
supplied 10-32 slotted screw

Obviously your drill/taps are different if threading for an S&S style main jet for the air bleed.

timber0472
06-29-2017, 1:42 PM
Apologies for the late reply. It does intersect because of course a blind hole would serve no purpose. You probably figured that out by now but if needed I'll pull a bowl from my new in box spare and remove the jet to illustrate.

Hahaha. Yea I figured as much. It didnt make any sense to me to be just a hole and not a tunnel. I just havent gotten around to do it yet. Damn job is interfering with my hobbies. Thanks for the info!!

Sky
06-29-2017, 7:09 PM
I prefer to plug the internal hole and put the air bleed jet hole on the outside.
There is a welsh plug in the air bleed passage just begging to be used as such. It stares you in the face as you sit on the bike.
Makes for quicker fuel free jet swaps...

You have the choice of machining the carb for an S&S style jet or the metric Mikuni style.

Revelator
06-29-2017, 9:08 PM
I prefer to plug the internal hole and put the air bleed jet hole on the outside.
There is a welsh plug in the air bleed passage just begging to be used as such. It stares you in the face as you sit on the bike.
Makes for quicker fuel free jet swaps...

You have the choice of machining the carb for an S&S style jet or the metric Mikuni style.

That's what I did on my E carb, Makes it so simple to swap the jet out. the location of the old air bleed
simply gets blocked off with a screw.