Exhaust pipe fit into the head.

[Plugsnpoints]

Recently I bought a complete system from a supplier.

The bike is a '58 standard 350 M16

The original was a snug push fit into the head.

The one I've just bought was a little slack, and consequently blows at the head. This causes it to backfire and upsets the neighbours even more!

My measurements are (new pipe-head end) 37.93mm, original pipe 38.4mm and the head opening measures 38.65mm

I won't name the supplier as I'm giving them the opportunity to sort it out, and they say they will.

Has anyone else had this problem?

Thanks chaps and ladies.

Andy

[lawrence]

If the supplier doesn't sort it then you can expand the pipe end by putting it over a mandrel (such as a stanchion) and tapping it gently as you rotate the pipe. Obviously only do it on the portion that is hidden in the head. Check frequently.

Alternatively, you can use some very expensive ultra-thin aluminium shim rolled round the pipe. A beer can is perfect. This is the lazy way of doing it. Works for me every time....

[Plugsnpoints]

If the supplier doesn't sort it then you can expand the pipe end by putting it over a mandrel (such as a stanchion) and tapping it gently as you rotate the pipe. Obviously only do it on the portion that is hidden in the head. Check frequently.

Alternatively, you can use some very expensive ultra-thin aluminium shim rolled round the pipe. A beer can is perfect. This is the lazy way of doing it. Works for me every time....

Thanks Lawrence, that's really helpful

I'll see if they sort it. Otherwise I'll try what you suggest.

[laxy]

I've had this problem just this week on my 55 single. I'd noticed for a while that the silencer would give a single pop on the overrun. It started to get worse so I stopped at the side of the road and gave the exhaust pipe a kick where it enters the head.the pipe moved into the head about half an inch and all seemed well for a couple of miles but then started poping again. When I got home I removed the exhaust and went to the local car spares shop and bought a tube of hylomar exhaust paste. I re assembled the exhaust pipe using the paste where it enters the head. The exhaust pipe fits into the head about an inch. Checked bracket was not straining to line up then ran the engine at tick over for a couple of mins to cure the paste. Left over night for good measure went for good run next day . Everything absolutely fine.

[Andy51]

Ordinary clear silicone sealant does the trick as well as Hylomar, and doesn't crack and fall out over time - as mine did when I used it back in the 70s when I rode a G80 as my everyday bike. Of course, Hylomar may have moved on since then. Andy

[P10]

This was a minor problem even when new and AMC fitters occasionally had to use a tapered steel plug driven in with a hammer to carefully spread just the very end of the pipe to make a perfect fit. However, your clearance is a bit extreme to do this and you are right to go back to the supplier in the first instance as the diameter appears to be too small. On other makes I have had similar success with exhaust cement but it will need renewing if you remove the pipe again.

[clive]

Recently I bought a complete system from a supplier.

The bike is a '58 standard 350 M16

The original was a snug push fit into the head.

The one I've just bought was a little slack, and consequently blows at the head. This causes it to backfire and upsets the neighbours even more!

My measurements are (new pipe-head end) 37.93mm, original pipe 38.4mm and the head opening measures 38.65mm

I won't name the supplier as I'm giving them the opportunity to sort it out, and they say they will.

Has anyone else had this problem?

Thanks chaps and ladies.

Andy

Years ago I had this problem and worked out that the pipe was the correct inside diameter to fit an early Iron head with the external spigot on the head rather than push fit in. As i had bought it for a push fit machine but had a spigot head one as well I never argued with the supplier especially since I had bought it at a jumble based on my assessment it was correct!