Fox 35 muffler

I have just bought a 40th Ann Fox 35 and find the muffler attachment holes are not tapped - is this normal?

What size tap do I need to use?

You're talking about the ones above and below the exhaust, and not the "ears", correct?

Yes, it is normal for this engine to have untapped blanks. Do you intend to use a tongue muffler? I guess I would drill and tap for 4-40.

If It's the 40th anniversary model,the bolts go through the ears,and the muffler is tapped.
Mike

Yes this is what I have - the bolts pass through the ears but the muffler is not tapped!

Duke Fox liked to do things different. Sometimes he had great ideas. Sometimes he just had ideas (as in, the Edsel was an idea.) His first attempt at a muffler was a muffler bolted on from the muffler side (good idea) but bolted on with one bolt above and one bolt below the exhaust (bad idea!). Not only were these very difficult to mount, but the holes where the muffler bolted into would allow crankcase pressure to leak out. They were, also, relatively easy to strip out the case, if you ddidn't strip the screws first.

When he next added "ears" to the sides, he made it so the muffler would bolt on from the opposite side of the exhaust and the bolts threaded into the muffler (good idea). But to make the mufflers backward compatible, he, also, made over/under lugs on the mufflers for a while (so the new mufflers could be used on older engines) and tapped the cases (compounding a bad idea, because now there wouldn't even be screws in the holes to seal the leaks from the crank case pressure) in case one wanted to use an older muffler on a newer engine. Eventually they quit tapping those holes above and below the exhaust, but used the same castings which included the "bosses" in the case anyway.

For a muffler, a muffler that will fit the 35/40 FP will, also, fit the Fox. (Oh, yes, did I mention that the first fox mufflers were tapped a little narrower than the width of the "ears"? So, now, when they finally made the muffler mounting lugs go all the way to the exhaust as nearly every one else was doing, they had to taper these holes in slightly to accomodate the earlier mufflers. "Backward compatibility"! That is what makes our computers so reliable and crash proof.

Hah!

>I have just bought a 40th Ann Fox 35 and find
>the muffler attachment holes are not tapped -
>is this normal?
>
No, it was not. And sorry for mis-reading your query!

>What size tap do I need to use?

The stock muffler was tapped for 4-40 bolts at the factory, unless they skipped a procedure in production, as seems to have happened to you. I did write you directly, back-channel, since I was having to wait and wait interminably to read or write much of anything here at SSW yesterday.

K.

If the Muffler holes are not tapped and the 4-40 screw will NOT go into the holes on the muffler, you can tap them with a 4-40 tap and use the muffler. IF for some reason you got one that was drilled out too big, or was stripped out, you can install a 4-40 heli-coil.
Bigiron

*sigh* The .19-.35 size tongue muffler straps right on after you pull a figure 9 on pavement and break off the stock muffler and the ear.....

Can you re-do these ears? Anybody try JB Weld or something? The tongue muffler looks like crap.....

You could also fashion a strap for the stock muffler - a liberty clip cut in half works well.

I also know of someone who sells muffler straps for 25p/37c a go!

Tony: You lost me on the liberty clip and the 25p/37c.

I have a Fox36 with the over-under lugs, Leonard you are right it is a REAL pain mounting the muffler.
My question is, What size are the screws holding the muffler on ?
I have lost one and can't find anything to fit.

I think those screws are a 3-48. Duke was never one to follow the crowd. He did use American threads, though. Again, as you discovered, this was not one of his better ideas. (Good idea to be able to mount the muffler from the muffler side. Bad esecution of idea because the muffler gets in the way.)

Hi Currell!

25 pence/37 cents!

A liberty clip is a circular clip with a single screw which tightens it - used for attaching hoses to a tap (fawcett) - cut it in half and it makes a decent muffler strap!

Now I know what you are talking about; a radiator clamp.

It's even worse in the car world with these US/Brit expressions. Like ground/earth, top/hood, hood/bonnet, spanner/wrench, fender/wing, dash/fascia, etc.

How we ever defeated the Nazis with this language barrier is anyone's guess.

Hi Rob Stagis
As a matter of fact I have had another ear welded on my Fox, just be sure to find a welder who knows how to work with small things and that he puts the case on ice while he's welding, I had this done 4 years ago and it's still holding.
Good Luck
DW