Just got a new to me R100RS. Tried to remove the exhausts and the left nut galled and stripped out the threads on the head. The other side looks to have been repaired once upon o a time. So, I need to repair or replace both heads. What 's the advice? Are they repairable or should I just lok for new heads?
The one previously repaired looks ok - why replace it? There are a couple options (in my book) for the mushed threads. I've recently heard that it's possible, using a thread file, to bring the threads back to new condition. Never tried it myself, but it's easy and cheap enough, just purchase a thread file. The other solution is to send it to Paul Sturges in Newberg Oregon. It'll look brand new (functionally as well) when returned and shipping both ways will likely be a third the total cost.
I don't know who does it around here but when I was with the BMW dealer in Canada, we used to have the threaded area built up with weld then have new threads turned back on. It looked quite good and wasn't very obvious. The real trick is to stop trying to force off the nut, as soon as it starts to bind STOP and split the nut. This will save the threads at only the cost of a new nut. When the threads get stripped off by the nut galling, both the threads and the nut will need to be replaced. Yes, when you look inside the nut the threads will look ok but when you try to "work" the nut onto the new threads, there's a good chance you will now trash the new threads.
What condition are the valve guides ,valves and seats? No sense sending them out unless the rest are ok. Or have them reworked and repaired at the same time.
They 'look' fine, but this is going to be a frame off resto, so I will have them completely done over while the threads are repaired. Hopefully, Sturges can do the whole enchilada. I'll do the rings and check the barrels for wear while I'm at it.
Carl..i.e. flying teapot does the repairs too. http://www.flyingtpot.com/main.htm the thread file works good for slightly boogered threads
http://www.tytlerscycle.com/searchresults.htm?q=ssaabmw+exhaust+nut+kitzz~ I bought a set of what Boxa Bits posted. Pretty cool and eliminates the weapon sized spanner in your saddle bag.
And also: Randy Long Long's Mechanical Services R.D. 1, Box 685-K 74 Risbon Road Honey Brook PA 19344 610-286-5870 to give plenty of choices for future Searchers. The big secret? yearly, back the nuts off, clean the threads with a brass-bristle brush and reassemble with plenty of anti-seize. --Bill
That's how Paul does it - cuts off the junk threads, welds up the area, then cuts new threads in the lathe. Like I said, you won't be able to tell it was ever repaired. As for the previously repaired head, he can fix that too. And yes, he replaces guides and seats if needed, as well as fin repair. He's been doing this for 35 years. I hate to mention his name because I don't want him so swamped he can't get to my stuff reasonably quick!
