R65 exhaust crossover tubes? spec rear tube too big? 26mm vs 30mm ID?

[rustedframe]

I pulled the entire exhaust of this R65 to clean it.  Both crossovers were in bad bad shape, so I pulled them off.   That was fun.

I went to a few BMW parts sites (Max's, Realoem) and bought the "stock" crossover tubes listed for an '83 R65.

But what I got in the mail doesn't fit the headers.  Both the front and the rear stubs on the headers want a crossover with an ID of 26mm.

The stock part #'s gave me a shorter crossover (~200mm) with an OD of 26mm.  That works.  But the other longer crossover (~255mm) has an ID of about 30mm.  That's too big.

I was wondering if anyone else has hit this.  The rear tube at Max's is 18111337234.  That's about 255mm with an ID of 30mm.  Maybe I have non-standard headers? 

[mrclubike]

I think they sent you  the wrong pipe
Both my front and rear are 26 mm ID
I know this is correct because I have replaced them with the OEM BMW ones
 
I would not buy the OEM ones 
The ears fell off in less than a year
Not really a big deal because they work just fine with out them

[Bob_Roller]

I vaguely remember a member here using a chrome vacuum cleaner extension tube for a crossover pipe replacement .

[Justin B.]

I'm not sure if the front and rear are the same but on the R65RS I used a piece of 1" electrical conduit.

[dogshome]

I think electrical conduit definitely fits the b for bodge category 

[Barry]

I vaguely remember a member here using a chrome vacuum cleaner extension tube for a crossover pipe replacement .

I remember that too Bob, it was an Electrolux tube and a long time ago. We can read how it went.

https://bmwr65.org/smf/index.php?topic=2536.msg26549#msg26549

[mrclubike]

I will defiantly go the Stainless route from Motobins the next time
I suspect the OEM steal don't last that long since the clamps have broken off already

[dogshome]

The Keihan stuff fits very well and is built to last. I luckily got the mufflers second hand (30 years old) but even the bobbers and choppers still want the front pipes. Without crash damage, they will last pretty much forever. Very solid and look unlikely to fracture or split. I've had a couple of pops in the exhaust from kick back or turning the ignition when primed and there is no sign of anything moving, rattling or stirring in the slightest.

My only criticism is that they are very quiet. No chance of rattling granny's china set or slumbering Kia drivers.