Exhaust pipe header clamps

[jdub6092]

Two of the exhaust head clamps on my 81 GS650E were cracked and broke when torqued.
Tried to use different high heat epoxies and puttys along with steel dowels inserted, but all attempts eventually failed.
Finally took the pipes to a welder, but the material (cast aluminum/zinc?) doesnt hold up to welding.
Looks like the only real option is to replace the clamps which requires cutting the welds on and removing the flange piece, then installing a replacement clamp.
Problem is that the clamps are integrated exhaust parts and not individually available.

Several GS models in the 79-82 year range do have replaceable clamps that are available, but I'm not sure if any of these would fit on my bike.

My dimensions are approximately as follows:
Pipe diameter: 35mm
Pipe Flange diameter: 45mm
Clamp bolts distance: 55mm
I would guess that the clamp inside diameter would need to be around 37-40 mm

One type available seems to be combatible with the 850 and several other models.

Any help on this would be much appreciated.

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[jdub6092]

Likely an issue that very few have dealt with.
I purchased some used clamps from an 81 gs850 as it's clamps appear to be removable and held in place by a couple of collar insert pieces.
The clamps are heavy duty steel and not the brittle light weight composite used on 650s and a few others. The fins extend too far out and the bolt hole spread is a little bit too wide, but can be modified by grinding and a slight elongation of the bolt holes.

I will still need to have the welded pipe flange collars removed to install them.
Going to try a straight die grinder with tungsten carbide burr bits. From reading several articles on removing hardened steel welds in tight spaces, this could take anywhere from 30 minutes to 8, 9, 10 hours.

 

[jdub6092]

In a last ditch effort to score some OEM exhaust clamps, I bit the bullet and purchased a full exhaust from a 650GL for an insanely good price with free shipping. Single pipes in poor to fair shape were asking for the same or higher $$. This set was obviously well cared for as the chrome still has a mirror shine and overall excellent condition.

I was planning on hacksawing two of these pipes on the bottom weld to get the clamps, then reselling the remaining two. Now I see this would be a crime for such nice pipes.

I also now see that the center and right pipes actually fit my bike well, so maybe I just swap them out, at least temporarily to get the bike running again.
From what I can tell, the GL pipes only difference from the E is shaft drive clearance and somewhat quieter.
Anything else to consider?

 

[jdub6092]

I have found some clamps and carefully hacksawed the broken ones off.

While I can see that integrated clamp replacement on these models is basically unheard of, I'd really appreciate some advice on which welds to remove, either from the collar flange as pictured above or the first bottom pipe weld that holds pipe pieces together.

Removing the collar flange weld from the pipe would prevent the need for precise realignment of the pipe.
However, Im wondering if the collar flange is first press fitted and wont move forward after the weld is broken.

Again, Im assuming few have had to deal with this, but if anyone has some deeper knowledge about exhaust construction on these models please chime in.

 

[crazyramen]

Haven't got any advice for ya but just wanted to say good luck and keep us posted on the results!

I might've tried to source/fab clamps that slide over the flange with those collars you put in after to secure it. Horrible description I know, but here's a parts diagram for my Honda xl250 that shows what I mean - part #2 is the collar

 

[jdub6092]

I wish I had those type of clamps with the slide on collars. Unfortunately, mine have a single large diameter collar welded on, so the clamps are integrated and not intended to be replaced.
Since I now have some spare clamps (meaning that the supplier couldnt salvage his pipes and cut them off for sale), I will start the slow process of cutting the collar welds tomorrow.