Hole in manifold

[goxu1]

What size is the small hole on the underside of the manifold meant to be ?
Mine needs drilling out but don’t want to make it too big

[Glen]

Hi,
The hole is small.
You could try using drill bits in a vice grip pliers, no electric drill, and turn them in by hand.
Then you can probably tell when the bits are cutting carbon or dirt, or cutting metal.

[Gary Dotson]

I’ve never measured one but I think it’s about 1/8”.

[Bill V in Md]

I am assuming that the hole in my 48 Cub manifold has not been altered. It is a tad larger than 5/64". I have a bicycle spoke that is 0.08" diameter, and it fit through ok, but was not tight.

[goxu1]

Close enough to 2mm for me
Thanks

[Bill V in Md]

Close enough to 2mm for me
Thanks

Aha, forgot you are from down under.

[goxu1]

Slightly off topic , but is the manifold the same for a cub and lowboy with an underslung exhaust ??

[Jim Becker]

The same manifold, a special elbow in place of the vertical pipe turns the exhaust back for the underslung pipe to clamp on. In '75 the manifold was changed to the next size larger pipe thread.

[goxu1]

Just wondering as there is a good looking manifold on feebay with the right angled elbow
It’s advertised as a lowboy manifold
I didn’t know if there was a difference or not

[Jim Becker]

A lot of sellers on sites like that one don't go down the path of what all something fits. They just list what it came off of and let the potential buyers decide for themselves.

Edit to add:
I was only talking about the offset Lo-Boys. The numbered Lo-Boys (154, 185,184) all use the manifold with the larger outlets as used on the Cubs from '75 on. I didn't check, but believe some of the power units add more complication to the story.

[Peter Person]

Close enough to 2mm for me
Thanks

Aha, forgot you are from down under.

2mm is just a hair over 1/16". 4mm would be closer to the 1/8" suggested.
As a place to drain water/condensation, the surface tension of water is such that even an 1/8" hole may not be large enough.

[Jim Becker]

2 mm is an almost perfect match for "a tad larger than 5/64". Without even looking at one, the 1/8 answer seems closer to right. Most I look at have a lot of rust in them, sometimes completely plugged. From the comments here, I think Bill V is the only one that actually looked at one.

[Gary Dotson]

I looked at an aftermarket manifold, yesterday, it was 1/8”.