Exhaust noise surging on cruise control. And lack of centre exhaust mounts?

[Pistachio]

My exhaust has been blowing a bit lately. I've noticed that with the cruise control on at 70 the noise surges loud to quiet roughly every second. It just constantly happens, making a horrible booming sound. Last week I took it to the garage and they said it was blowing between the connecting pipes in the middle. They resealed it and it sounded quieter, but not quite right. I've got a miltek rear silencer which normally sounds really nice, so I know something is still not quite right.

When it was on the ramp we were noticing how there isn't any support in the middle section really. Is that normal? And can anyone think what could be causing the surging? I'm going to have to take it back for them to have another look

 

[AlexW]

Most likely the join between the cat and centre section, it has a silly flared join, I forget the proper name. Common to sleeve it as this solves it forever.

Also, there should be a mount just in front of the fuel tank, often stretched etc, recommend replacing it, £16 from Adam at Wolverhampton IIRC.

 

[Pistachio]

I think it might have been that connection that was loose. I just had the two rear mounts replaced recently. Not sure about the fuel tank one

 

[Pistachio]

It was the clamp on the adaptor between the cat and the miltek pipework. The threads on the clamp were stripped, so the garage that re sealed it last week doubled up the nuts instead of replacing the bolts. I took it to my trusted (but slightly further away) garage today and they have sorted it. Sounding sweet again