Exhaust header leak - leave it alone or fix?

[gog]

The exhaust header on the LHS of my 1100GS has a slight leak, I can see if puff for a few seconds when started from cold but it soon disappears. The nuts/studs are in an *awful* state and is putting me off trying to remove them to install new studs and sort the leak as ive read its very common for them to shear causing somewhat of a ballache. I cant afford at the moment to send the heads away for repair if a stud shears and extraction fails, so I have just ;eft it well alone.

Occasionally I get a pop coming off throttle, but it doesnt bother me and is rare.

Question is does a slight header leak have much (any) effect on the running of the bike? Fuel economy, balance etc. If its not doing any harm, im leaning towards not fannying about with it for now.

 

[robc]

Sounds like heat expansion is sealing the gap for you. My header studs are in a similar state to yours so I'd be inclined to leave it until it becomes a more permanent leak. In the meantime I'd be saving some pennies for the inevitable.

Regards

RobC

 

[robc]

Mind you.....I have had to have exhaust studs extracted on another bike. I local tinkerer was recommended to me who did a pair of studs for about £60 I think. Studs were drilled out and helicoils inserted with the head still on the bike (125cc single it was). I fitted the new studs and all seemed well. My point is that it might not be earth shatteringly expensive should the worst happen.

Regards

RobC

 

[gog]

cheers rob. suppose it would depend on how many break. they really are in a pitiful state, they dont even look remotely like nuts now. originally i assumed that someone had welded them in!

 

[(RIP) Tunneruk]

Here's one I did on my (use to be) R1100s...

Here's the thread ...

http://www.ukgser.com/forums/showthread.php/428371-BMW-R1100S-Repaint-Refresh?highlight=r1100s

Well that was an interesting couple of hours!

The mission - To extract the rotted exhaust stud.

I started with a bit of heat and the old 'double nut' trick ...... No chance, the stud just snapped.

However, there was still 15mm of thread showing so I would another nut on and welded it on, the hope being that the heat transferred would help release the thread, each time I just managed to snap a bit more stud off .... five times in fact

IMG_2101 by tunneruk, on Flickr

IMG_2102 by tunneruk, on Flickr

So, undeterred, I went back to basics and got stuck in -

IMG_2103 by tunneruk, on Flickr

IMG_2104 by tunneruk, on Flickr

I was very lucky in that I managed to drill out the old stud and just leave a coil of thread which came out like a spring. I ran a top down the hole and wound in the new stud!

IMG_2105 by tunneruk, on Flickr

IMG_2107 by tunneruk, on Flickr

IMG_2109 by tunneruk, on Flickr

The result of this is that I've got naff all painting done today!

 

[gog]

Thanks Tunner - doesnt look that bad, I could probably manage that myself even if i need to use a helicoil if my drilling is not as precise as yours.

Im surprised the heat from welding the nut on didnt work here, it has always served me well on the land rover.

 

[(RIP) Tunneruk]

Im surprised the heat from welding the nut on didnt work here, it has always served me well on the land rover.

Me too, I was sure it'd have freed off the stud but all it did was break off about the last 3mm of the stud. Return and repeat.

I will say, I did get VERY lucky freehand drilling that stud out so straight and true. Well I say lucky, I am a bit godly and awesome so I didn't even blink

 

[gog]

Ill give it a bash when the frost hits and see what happens.

 

[(RIP) Tunneruk]

Ill give it a bash when the frost hits and see what happens.

My advice is this. Only attempt this when you're physically and psychologically able to accept the possibility that you'll have to take the head off if it goes wrong. I'd say that your chances are 50% (No disrespect!)

 

[gog]

no disrespect taken at all. in fact i would say 50% is wildly generous. i've had the heads off my other bikes for various reasons so this ones only a matter of time

 

[Steptoe]

My advice is this. Only attempt this when you're physically and psychologically able to accept the possibility that you'll have to take the head off if it goes wrong. I'd say that your chances are 50% (No disrespect!)

Less than 50%. Don't forget the 1100GS has three studs per head. Not two like in your pictures.

 

[gog]

One thing im not 100% on is whether the studs break when removing the nut, or when trying to remove the entire stud once the nut has already been removed (the replacement kits ive seen are studs and domed nuts)

The "nuts" on mine are no longer recognisable as nuts, more irregular blobs of corroded ex-metal. I would be surprised if they didnt crumble away to dust when lightly touched with a socket. If the nut comes off (or can be cut offf), allowing removal of the exhaust, can the threads of the stud be cleaned and just stick a new set of nuts on?

Sods law tells me this of course wont be the easy solution im hoping for though...

 

[(RIP) Tunneruk]

One thing im not 100% on is whether the studs break when removing the nut, or when trying to remove the entire stud once the nut has already been removed (the replacement kits ive seen are studs and domed nuts)

The "nuts" on mine are no longer recognisable as nuts, more irregular blobs of corroded ex-metal. I would be surprised if they didnt crumble away to dust when lightly touched with a socket. If the nut comes off (or can be cut offf), allowing removal of the exhaust, can the threads of the stud be cleaned and just stick a new set of nuts on?

Sods law tells me this of course wont be the easy solution im hoping for though...

The problem you'll likely have if you're able to get the nuts off is the portion of stud which site within the exhaust flange. There's a good chance it'll look like a twilit!

If the nuts as in really bad shape then the stud will likely just snap if you put any tensile energy through it.

IMG_2096 by tunneruk, on Flickr

 

[gog]

haha bloody hell thats grim, a twiglet indeed. no wonder they snap.

 

[Rugged Path]

My exhaust closed nuts come off easily after 13yrs (1150GSA) because it is one bit of advice I heeded to have them greased. I use silver based grease.


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