Fractured Rear Header (AGAIN)

**Ghost** · 11 Sep 07, 07:42 PM

Has anyone had this occur this is the second time within a year or 6k miles. I welded it last time and as you can see it has fractured again this time in the heat affected zone. The wire is there just to hold it open for clarity. I shall weld it again and back purge it, but would be interested to know if others have had similar probs. It is a 2004 749

It has a Termi system on and yes I do feel high frequency vibes but its a Duke its meant to.

Phil

XP · 11 Sep 07, 07:59 PM

Quote:

Originally Posted by Ghost

Has anyone had this occur this is the second time within a year or 6k miles. I welded it last time and as you can see it has fractured again this time in the heat affected zone. The wire is there just to hold it open for clarity. I shall weld it again and back purge it, but would be interested to know if others have had similar probs. It is a 2004 749

It has a Termi system on and yes I do feel high frequency vibes but its a Duke its meant to.

Phil

Hi Phil,

Haven't seen this before buddy....

There must be some serious stress going through your pipework to make it do that......

If you get stuck for a vertical header pipe I've a couple of spares mate (No spare horizontals unfortunately)....

Andy

XP

**Ghost** · 11 Sep 07, 08:21 PM

Thanks Andy I did buy a horizontal ages ago just because it was cheap and new I will weld this again and se how it goes. It will last this year out now. Especially with my welding a candle and a length of fuse wire can weld cheese to butter.

Phil

**duke749s** · 11 Sep 07, 10:00 PM

By the looks of the picture it was mig weld previously, please correct me if I'm wrong. Unfortunatly Stainless steel seems to fatigue easier around the weld when mig welded. I would recommend having it tig welded if possible. I have had this problem with some one of prototype cats designed for an engine I had running on my on my test bed at work. It was stainless which had been mig welded. I lost count of the number of times they fractured in quick succession. The latest evolution is tig welded, I've yet to crack them. This is on an engine running flat out 6500RPM, 900c cat temps, glowing red hot for longish periods of time, not a problem.

I'm surprised it has happened in the first place, but again aren't the termi systems mig welded? I'm sure they look like they are!

**duke749s** · 11 Sep 07, 10:02 PM

Oh by the way if you can't get it tig welded easily and you could get it to me I can get it done at my work for you, shouldn't be a problem.

**Ghost** · 11 Sep 07, 10:56 PM

Thanks Kev, but it was Tig welded before, it was at the junction of the pipe to the casting. It did not weld as neat as I would have liked, hence the requirement for linishing. Thanks for the offer to weld but for my sins I am a qualified welder in mig, tig, mma and oxy-acytelene. So I would really get the **** taken out of me If I sourced it out.

Thanks again I know you meant well. This has occured twice now and no one else appears to have had a problem. It must be high frequency vibes doing the damage. I'll try a new one if this fails again.

By the way you wern't the 749 that I passed on the Kenilworth bypass last Weds from the Waterman and then came together at Whitley roundabout heading down Allard way? If so Hi.

Phil

**wrs71** · 11 Sep 07, 11:18 PM

have you tried heating it up before you weld it like you would welding cast, and cooling down in sand if its your cast part thats cracking,
If its cracking next to your weld on the tube try quenching it after welding, normally helps, another thing to watch is the crap on the inside of the pipe being drawn into the weld, are the down pipes stainless or titanium, if they are titanium and your stuck for a rod ,i may just be able to get a couple of rods to you.

**Ghost** · 12 Sep 07, 11:32 AM

Thanks WRS I am sure on the humble 749 that its just stainless. Priority job this morn when I got to work. It probably would have been cheaper for the company to go and buy me a new header.

Does anyone know if there is a sealing washer from the header to the link pipe for the rear cyl. The parts manual shows one for the front cyl but not the rear. I have a new one for the link pipe to silencer.

Phil

**duke749s** · 12 Sep 07, 02:44 PM

Quote:

By the way you wern't the 749 that I passed on the Kenilworth bypass last Weds from the Waterman and then came together at Whitley roundabout heading down Allard way? If so Hi.

Hi Phil,
No unfortunatly it wasn't, I probably wasn't allowed out to play that night!!!

Quote:

Does anyone know if there is a sealing washer from the header to the link pipe for the rear cyl. The parts manual shows one for the front cyl but not the rear. I have a new one for the link pipe to silencer

I pressume it's just the half termi system you have therefore it is the standard header pipe. If so then yes I'm pretty sure you should have a sealing washer fitted as the standard system would have. JHP should have them in stock, I just bought a set a couple of weeks when I put the standard exhaust back on my 749S before I sold it. They aren't cheap for what they are, about £5 a piece!!

**nelly** · 12 Sep 07, 03:03 PM

I've not seen that before?? Twice in a year, is real bad luck.
Have you checked your engine mounts? For it to break, there's got to be a stress coming from somwhere, and that's usually movement.
again, not seen it with s sbk, but have had a few ST's fail MOT's on supposedly shock wear, only to find the rear engine mount has loosened and the whole unit is moving in the frame.

**Ghost** · 12 Sep 07, 03:14 PM

Hi Nelly, because of the spring slip joints on the Ducati system the pipes are not under any forced stress. When its cold I can grab a pipe and move it radially.

Its going in to Mr Hackets next week for them to set the Power commander and throttles as its constantly stalling now since its run to the Ring and back.

An air leak at the exhaust could also be a contributary factor to the stalling. I'll mention the exhaust header prob to them anyway.

Phil

XP · 12 Sep 07, 05:27 PM

Quote:

Originally Posted by Ghost

Does anyone know if there is a sealing washer from the header to the link pipe for the rear cyl. The parts manual shows one for the front cyl but not the rear. I have a new one for the link pipe to silencer.

Phil

Hi Phil,

You should have 4 gause exhaust seal gaskets/washers to complete your system.....

1x Horizontal Link pipe to Horizontal Header pipe
1x Vertial Link pipe to Vertical Header pipe

1x Horizontal Link pipe to Rear Can connection
1x Vertical Link pipe to Rear Can connection

(3 small + 1 large)

Cheers

Andy
XP

**Ghost** · 12 Sep 07, 05:35 PM

Quote:

Originally Posted by XP

Hi Phil,

You should have 4 gause exhaust seal gaskets/washers to complete your system.....

1x Horizontal Link pipe to Horizontal Header pipe
1x Vertial Link pipe to Vertical Header pipe

1x Horizontal Link pipe to Rear Can connection
1x Vertical Link pipe to Rear Can connection

(3 small + 1 large)

Cheers

Andy
XP

Thanks Andy mybe that is the cause as there was not one from the vert header to link pipe. But strange that the my parts manual does not show that one either. The part number 79010091A says 2 off and the large one one off. but I think there should be one in the link to header also, well there is now anyway. I think this thread is closed thanks for all your input guys.

Phil

**Triple9** · 16 Sep 07, 05:46 PM

Not quite closed!

Was out and about today and noticed the bike felt a bit rough and started banging/popping on the overrun.Had a looksy at the rear header and seemed to be able to move it more than usual.Got home,stripped it down and found this.(see pic)
Bike is an '05 999S with 10,500 miles on the clock.

XP · 16 Sep 07, 05:56 PM

How weird is that......

Obviously a friday weld chap....

On a serious note, would be worth everyone just checking there header pipes for any signs of cracks etc.....

XP