How to loosen exhaust system?

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schrader7032
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Location: San Antonio, TX

How to loosen exhaust system?

Post by schrader7032 »

"Foot plate"? I'm not sure I understand what's contacting what...

Crossover pipe...that's the one behind/underneath the tranny?

The "vented header clamps"...what are those? Are those the finned exhaust nuts that create the seal onto the large threaded "pipe" that sticks forward on each head? If so, and they don't budge now, you should stop applying anymore force and cut them off. It's quite easy to gall the threads on the large OD pipe and that will ruin your day. You can use a hacksaw down to the point where you're nearing the threads and then use a cold chisel or something to expanding the nut so you can get it off. Of course, if you end up cutting them off, you'll need to completely remove the exhaust system in order to install new finned nuts and clamp rings.

And, once the exhaust system is off, you may be able to more easily deal with the crossover pipe and get things loosened up.

I had trouble getting off one of my mufflers for my R69S rebuild...only one would come off and the crossover pipe would not separate. With one muffler off and the finned exhaust nuts off (luckily, they spun off without too much effort), I could just barely wiggle the entire system forward and out from under the bike. With some help and generous soaking with both Aerokroil and PB Blaster, I was able to separate the other muffler. However, the crossover pipe remained solidly in place, which meant that the headers remained attached. No matter, I was able to reinstall as is.

But on those finned nuts, be very careful and don't get too hamfisted.

Oh, you might try some focused heat, but that might only boil off your penetrant and cause the chrome to discolor, so that might not help too much.

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

charlier
Posts: 10
Joined: Wed Mar 21, 2007 12:43 pm

How to loosen exhaust system?

Post by charlier »

Yeah, sorry, finned exhaust nuts is what I meant. Well, this DOES sound challenging. Might be better for now (as I have no plans to rebuild the exhaust system at this point) to work out some way to put a spacer either on the side stand's rubber bumper or on the place against the engine where it is supposed to rest. By "Foot Plate" I meant the flat plate that's welded onto the bottom of the sidestand to give it more surface area when it hits the ground and holds the bike up.

Thanks...

Charlie in NorCal.
--Charlie Rubin
VBMWMO Secretary
'67 R69S
'75 R90S

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schrader7032
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Location: San Antonio, TX

How to loosen exhaust system?

Post by schrader7032 »

Charlie -

My bad...I read centerstand, not sidestand. Now I get the picture. I just checked mine and you're right, if the stand is too long or the crossover pipe is too far forward, the flat part of the sidestand will hit the pipe.

Just to be sure, how long is the sidestand? I don't think Vech would sell you something you can't use, but I believe there are two lengths of sidestand. There's one for the R69S and one for the R69US. My R69S has the original sidestand. It's difficult to get a very accurate measurement, but I get about 10 inches from the center of the pivot bolt to the fartherest point on the foot plate.

Another way to tell the differences is in a relative way... The two stands are the same from the pivot point down to the curved tang that sticks out for catching the stand to deploy. The correct R69S sidestand has only about 2-3/4 inches from that tang to the farthest point on the foot plate. The R69US stand probably has another inch or so of distance...the R69US sits up a little taller so the sidestand had to be longer.

Hopefully you have the correct one. Beyond that, you'll have to get creative if you're going to create a different spacer to keep the sidestand from touching the muffler. Maybe there's a way you can restrict the movement by putting something up near the pivot point...

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

charlier
Posts: 10
Joined: Wed Mar 21, 2007 12:43 pm

How to loosen exhaust system?

Post by charlier »

Thanks, Kurt. My stand seems to be about 9.5" long, but if it was longer the problem would be worse. I took another look and it's actually hitting the muffler pipe before it gets to the crossover. I'm going to try to get creative about it. Vech said that the mufflers must be in the wrong place, but I can't see any other place where they could be, frankly.
--Charlie Rubin
VBMWMO Secretary
'67 R69S
'75 R90S

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schrader7032
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Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

How to loosen exhaust system?

Post by schrader7032 »

Sounds like you have the right sidestand. Actually, my sidestand is somewhat difficult to deploy. The small rubber bumper on it is a very tight fit past the underside of the muffler. It'll move in and out but it's tight. Actually, I tend to use the centerstand all the time. It's quite a bit easier to use than my /7, so I figure I'd do that instead.

There's a circlip or washer that's used up by the pivot pin. What if you were to locate it on one side or other and see if that translates the whole sidestand one way or the other and maybe clear the muffler better. I guess you still have the problem with the length such that it'll contact the crossover tube. One thing at a time I suppose.

Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Allan.Atherton
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Re: How to loosen exhaust system?

Post by Allan.Atherton »

... I can't get... the vented header clamps on the cylinders to budge. Tried using a spanner tool from the original BMW toolkit, but no dice....
The finned header nut requires a special fingered wrench that slips into the fins:
http://w6rec.com/duane/bmw/exhaust/extool1.jpg
The spanner in the toolkit works on the chromed steel header nut on the other bikes, but I don't think it works well on the R69S nut. The spanner might mess up the hole in the soft aluminum nut, and I don't think the spanner can exert enough torque anchored by that one soft hole.
As noted, if the nut does not loosen with a fair amount of torque from the finger wrench, or if it loosens but then immediately jams, cut the nut off to save the threads on the cylinder head. Hopefully the previous owners have not buggered them already.
Read "Installing the BMW motorcycle exhaust system" toward the end of this page:
http://w6rec.com/duane/bmw/exhaust/index.htm

charlier
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Joined: Wed Mar 21, 2007 12:43 pm

How to loosen exhaust system?

Post by charlier »

Thanks for the tool tip, Alan. I tried the tool in the original kit and no, it does not exert enough force on the aluminum finned header nut. I'm going to leave that end of things alone for now and try to work out something for the sidestand. I have a lousy back and while I can (and do) use the centerstand in the garage, I'd rather not have to when I'm just out riding and parking the bike temporarily somewhere.

Thanks for all the input, folks!

Charlie Rubin in SF Bay area...
--Charlie Rubin
VBMWMO Secretary
'67 R69S
'75 R90S

Allan.Atherton
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How to loosen exhaust system?

Post by Allan.Atherton »

... I have a lousy back and while I can (and do) use the centerstand in the garage, I'd rather not have to when I'm just out riding and parking the bike temporarily somewhere....
I have had a back operation and use a technique of putting the bike on the center stand using the leg as a lever that does not involve lifting. You actually press your fingers down on the seat and handlebar to steady yourself and bike, as the bike is rising onto the stand. Email me and I'll send it.

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jerothe7301
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Center stand technique

Post by jerothe7301 »


I have had a back operation and use a technique of putting the bike on the center stand using the leg as a lever that does not involve lifting. You actually press your fingers down on the seat and handlebar to steady yourself and bike, as the bike is rising onto the stand. Email me and I'll send it.

Alan, Could you send me a copy of this?

Thanks! Rick (richard@jerothe.com)

Allan.Atherton
Posts: 503
Joined: Fri Oct 27, 2006 3:00 am

How to loosen exhaust system?

Post by Allan.Atherton »

OK, will send.

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