Exhaust Stub repair.

[Damien]

I have just bought new stainless exhaust down pipes and collector box for my R80 g/s. The old exhaust was shot and had the headers welded into the collector box. Anyway, the right header rose nut was seized so i got out the dremel and cold chisel and cut the nut off. I had to cut the headers also due to the welding.

On examination, the exhaust stub threads on one side are in poor nick. The previous owner told me a mechanic had tried to get the nut off but to no avail. If they are fecked, to whom do I send the head for repair?

The bike has 75,000 km on the clock, so the valves probably need doing also.

I will try to clean up the threads with a thread file in the meantime.

 

[B Murr]

mOTORWORKS DO A MOD HERE http://www.motorworks.co.uk/bmw/pro...&partcode=VR&header_text=&header_text_image=0

 

[Damien]

Thanks, I had seen that, but I would prefer to repair the stub and have it as standard. I don't think a repair would be much more than that anyway.

Just need to find an engineering specialist who can do it, if I can't clean it up.

 

[VAL. H.]

Thanks, I had seen that, but I would prefer to repair the stub and have it as standard. I don't think a repair would be much more than that anyway.

Just need to find an engineering specialist who can do it, if I can't clean it up.

Jill's 100GS Para has had new threaded collars put on both heads. The heads where gas flowed by Jim Cray in Kent. So I'm guessing he did the job.
Cray engineering 01795 538282, in Sittingbourne I beleive.


HTH Val.

 

[Damien]

Thanks Val,

I will give them a call.

 

[DrFarkoff]

Call The folks at motorworks +44 (0) 1484 353600 and motobins they offered this recollaring for the airheads
My first restoration had them about £110 plus post for 2 heads I believe

Steve at Scriminger Engine Developments is another port of call

Thanks Val,

I will give them a call.

 

[Steptoe]

Everyday job for [URL="http://www.blrengineering.co.uk/gallery.html"]BLR[/URL] engineering.
All the work done in house, not farmed out like other suppliers/providers.

 

[Damien]

Many thanks for all the replies guys.

 

[Damien]

Well I finally got around to fitting the new exhaust today, and such is my luck that BOTH exhaust stub threads are knackered. So seeing that I have to send them off to get repaired, I suppose I should get the valves, guides and seats done. I have seen Swiss intervalve parts offered by motobins and the likes, and also K-Line valve guide lining from the cylinder head shop.

Does anyone have any recommendations as to what and whom to use? And should I do anything else while I am at it?

The bike is an R80g/s and has 75000 km and no service history. I plan on keeping it very long term so doing things the best way(only once) is what I am after.

 

[Steptoe]

Well I finally got around to fitting the new exhaust today, and such is my luck that BOTH exhaust stub threads are knackered. So seeing that I have to send them off to get repaired, I suppose I should get the valves, guides and seats done. I have seen Swiss intervalve parts offered by motobins and the likes, and also K-Line valve guide lining from the cylinder head shop.

Does anyone have any recommendations as to what and whom to use? And should I do anything else while I am at it?

The bike is an R80g/s and has 75000 km and no service history. I plan on keeping it very long term so doing things the best way(only once) is what I am after.

BLR will do everything. Including machining their own valve guides to fit your valves, rather than fit off the shelf guides with a set clearance.

 

[Damien]

Thanks for the very prompt reply Steptoe,

Just spoke to BLR, they are doing it all, with the valves I shall supply. I am going to do both inlet and exhaust.

Hopefully no further surprises will emerge during the job.

 

[Mike Wilkins]

valves

Hi Omen
what valves did you decide to use ? Is there a benefit to use the Swiss Intervalves you mention above, over the oem ?
Cheers
Mike

 

[Damien]

Hi Mike,

I am still in the middle of researching various valves, so still none the wiser yet. I will post up what I find though, hopefully someone on here can share their own knowledge/experience.

Damien

 

[Beemerboff]

According to th local head guy you cant put K line liners in existing" bronze"guides like the BMW ones
The main advantage of the Intervalves seems to be cost - Motobins supplied a set of 4 valves and guides etc for less than BMW Oz want for one exhaust valve and they are top quality.

 

[Damien]

Thanks for that Beemerboff.

I have priced valve kits from Moto-bins and the BMW originals are about 35% dearer than the Swiss ones.
I have also done a compression test, the right cylinder is 150, the left is only 120. Valve clearance is a bit tight , but the valves are closing fully. However, looking down the inlet and exhaust ports the bits I can see don't look too bad. Also I can see crosshatching on the cylinder bore so I think its safe to assume the engine has had work at some stage in the not too distant past. It was smoking on start up so it could be the rings on the left pot.

The previous owner only had it for 2 years but the original owner had it for the previous 22. I know he lives in Ireland so I think I will try a bit harder to track him down.

Life is never dull with these old machines, but always lots of help on here

 

[(RIP) Proff]

Don't worry about smoke on start up, especially if it's been on the side stand.
"They All do that Sir"
The cross hatching is the ORIGINAL honing marks on the bores, as they can not be rebored... Bung a set of rings on the pistons along with what you are already doing, and Bobs your mothers brother

 

[(RIP) pastyman]

I had mine done on Bertha my 100GS. I went for a system similar to the K-Line, where bronze inserts are fitted to the original guides. The seats were then recut with a computer/lazer guided cutter and new valves fitted. As I understand it the tolerences in the guides are much closer. the job is quicker to do and there is no risk of "tearing the head as when old guides are forced out. They can be easily replaced when they do eventually need replacing. They have been in for about three years now. The engine certainly seems responsive and the oil stays clean for a lot longer. I believe the system is common in the haulage industry where the engines do very high mileages and also in racing circles. .
I am well pleased with

 

[John Roberts]

Also I can see crosshatching on the cylinder bore so I think its safe to assume the engine has had work at some stage in the not too distant past.

Life is never dull with these old machines, but always lots of help on here

I've just done some work on mine and it was nice to see the crosshatching as you said, unbelievable. There was no wear that I could measure by measuring the ring gap as Proff said, it was the same at the top, middle and bottom of the bore.

I would add that there was remarkably little sign of wear anywhere on mine, engine of gearbox, a tiny amount of scratching on a piston skirt, NO recessing of the valve seats, but some pitting on one inlet (why not on the exhaust, I wonder?) very little on the valve stems, 0.0002" if I remember correctly, and although I couldn't measure the guide wear the wear judged by feel was negligible. The gearbox did have one knackered bearing, the front output shaft bearing (is that the one that usually goes, anyone?) and the other five were perfect, although I did change them all. Oh, except for the inner race on the input roller bearing, couldn't be arsed as it looked and measured perfect. No wear on the forks or cams, minimal on the dogs, and original machining marks visible on the teeth.

As the oilchanges have been, err, sporadic should I say, throughout its life- 28 years but only 65,000mls I really didn't deserve such a pleasant surprise. Good motors, these boxers, they should go far.

 

[Voyager]

Motobins replaced the exhaust stubs and valve guides on my R80RT a few years ago - I thought they did a good job.

This is what the stubs looked like.

Bob.

 

[Damien]

Well, I got the heads back from BLR engineering- very impressed. Easy to deal with, quick turnaround and a quality job.
<a href="http://www.flickr.com/photos/43883611@N07/4750305674/" title="IMG_2836 by Damienoc1966, on Flickr"><img src="http://farm5.static.flickr.com/4101/4750305674_71d4d085e6.jpg" width="375" height="500" alt="IMG_2836"></a>
I also had new valves, guides and exhaust seats installed too.

<a href="http://www.flickr.com/photos/43883611@N07/4750297578/" title="IMG_2835 by Damienoc1966, on Flickr"><img src="http://farm5.static.flickr.com/4140/4750297578_6c3a574874.jpg" width="500" height="375" alt="IMG_2835"></a>


While I was at it, I also put in new rings and as the pushrod tubes were fecked, new stainless items went in too.

Put it all back together and she started first time!

I need to have another go at the balancing as its not quite right. Overall , I am now a happy camper. she just needs a bit of running in.

<a href="http://www.flickr.com/photos/43883611@N07/4750297094/" title="IMG_0221 by Damienoc1966, on Flickr"><img src="http://farm5.static.flickr.com/4098/4750297094_a68ab241e6.jpg" width="500" height="375" alt="IMG_0221"></a>
Thanks to all for the advice and apologies for the crap photo's.