Help !! R100GS, exhaust stuck in cyl head

Mike Wilkins

Mike Wilkins

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Have removed my heads for a refurb. One non-stock stainless header is stuck fast in the cylinder head. Have tried much force and heating to no avail !! - it seems firmly welded in place.
Is there a 'trick of the trade' or some magick elixir to soak it in to free it
Cheers
Mike
 
Well that was daft taking the head off with the pipe still in it

The solution is to start the bike and go for a wee ride till it heats up and a couple of appropriate taps with a mallet should sort it

It will be difficult to get enough heat into it with it off but a roofers torch and a good soak in diesel should suffice
 
Thanks Dr but it was too late for a wee ride having drained the oil and removed the front end for headstock bearings !!
It was a case of what the f*** to do next so we took it off to put in a vice
 
Aluminium oxide resulting from the electrolytic reaction with stainless steel is much more bulky than it's base metal.
If soaking in diesel for a few days has no effect, the stainless pipe stub might have to be a cut out with air burr grinder.


Sent from my phone with mangled spelling
 
We had a similar thing with David Nimrods bike a few weeks ago. The only solution was to slacken off the exhaust nut to let some hot gases blow by and a big chunk of wood propelled by a lump hammer. Once out the problem was down to a build up of carbon in the exhaust port. A session in the ultrasonic sorted most of this out the rest was simply scrapped out with a screwdriver. It was touch and go if it was going to come out and took a long time to get it moving.

I wouldn't fancy doing it with the head off the bike though. As Bendy says above a grinder of some sort is going to be the only option.
 
try putting the cylinder head in the oven then with some thick gloves try to remove it ! thats what I would try :D
 
my stainless pipe was stuck in the head too days of bashing and heat mooved it in the end ,bloody hard work
 
get one of my new oversized header setz look the dogs bollucks can be removed in seconds and easy to replace any damaged pipes i hope to get one on the dyno next weekend :D
 
Progress report

Knackered threads on one head were repaired by BLR engineering
The other head, with the stuck exhaust header already had a bronze insert and the header had to be cut out - it seemed to be cemented in place with something very strong !!
-- so I had to buy another set of stock headers from Litelfun - thanks Nigel
-- so now I have 2 inserts with good threads, but the exhausts seem a very sloppy fit into the inserts, is this normal ?
Do the 2 seals (inner split triangular section and outer of softer metal) take up the slack when clamped on with the exhaust rose ?, or should I use some kind of sealant. This I would find worrying in case everything gets cemented together again
Thanks in advance
Mike
 
chrisshrops said:
with LOTS of copper slip on the threads
Click to expand...

Noo! Not copper slip. It burns on and can make things much worse.

Optimal TA anti size paste is the one. rated at very high temperature and has the advantage of not needing the nuts done up as tight. Motobins Part No.95805 - BMW specified for the exhaust nuts apparently. For what it's worth I swear by the stuff.
 
I just put the copper paste on the header that slides into the head and the copper rings nether had any problems yet I wouldent over tighten them thou and its allways best to warm the engine up first before trying to remove them againe if they have been on a while its allso good once or twice a year to just lossen them of and tighten them back up againe !!!
good to hier they arived ok , many thanks
 
Fundamental flaw !!

My exhausts (both old and new) are 38mm OD
I have discovered there are also 40mm which I think is what I need for my heads. Doh
I think I will try to create packing spacers from my already cut stainless pipe to get the bike going and look for a 40mm setup in the meanwhile
Thoughts ?
Cheers
Mike
 
Mike,

40mm headers were fitted to pre 81 bikes fitted with 40mm carbs. Somebodies fitted the wrong ones if they've done that.

There are no standard 40mm headers for a GS.
 
Hi Rob
When I took the heads to BLR he had the inserts already made up, and said he had not done one for a couple of years. I wonder if he once had a batch made for 40mm
The other seems the same, as u know the bike was in Scotland before I had it so someone up there did the same, and someone had used a filler to take up the slack which eventually welded the pipe in place (the ok one had the stuck header)
What do u recommend, perhaps with the stock seals clamped in place with the rose all will be ok but I don't like the space between the stub and the pipe seems wrong
Cheers
Mike
 
You could get osmc http://www.osmc.co.uk to make a pair of down pipes that flare down from 40 to 38mm or contact pipey who used to be on this site. The other options a 1mm thick tube to make another packer but I wouldn't be too keen on that.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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