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paul25g
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Joined: 07/25/2012
Posts: 88

Hi Guys,

I've got a '58 R60 that I got in pieces and am in the process of putting back together. This bike has the larger 6.5 gallon Sport tank. I've been trying to restore it to original as much as I can.

Everywhere I look, the front fuel tank mount bolt is described as M8X1X100. Going through the bag of bolts that came with this project, I found a bolt that matched that description. It is a shoulder bolt with only the last inch or so threaded.

As you can see in the attached pic, this bolt is so long that I can't secure the tank. Obviously, if more of the bolt were threaded I could tighten the nut up, but the real question is, why should this bolt be so long?

So here's my questions:

1. Is 100mm length listed for this bolt a typo on every parts list (and Vech's website) I have seen?
2. Would the sport tank use a shorter bolt than a standard tank?
3. Am I missing some kind of spacer for the front of the tank that would take up more of the 100mm bolt called for?

I realize I could just use a shorter bolt and call it a day, but as I said, I'm trying to do a pretty spot on restoration and would like to know what the deal is with this bolt. I can't imagine that a bike that is so well put together in every other way would have a super long bolt here that isn't necessary.

Any input is appreciated!

Thanks!

Paul

  • front_fuel_tank_mount_bolt.jpg
Beemer100
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Germany
Joined: 05/15/2018
Posts: 51
Paul, just checked my R50 and

Paul,

just checked my R50 and it has a 70mm long bolt which fits nicely considering the washer and the nut. I also checked my R69S (however, only through fotos since the bike is not in my garage) and it also has a bolt which ends right after the tightened nut. So, my assumption would be that 70mm is the proper length. Oh, BTW, both bikes have the Mayer Sports tank.

One thing you have to take care of when you mount the tank to the frame ... make sure there is no stress whatsoever when you tighten the bolts. If there is little gap between the "ears" of the tank and the frame .. please shim it. You want to avoid that the bolt bends the mounting ears towards the tank. Once filled up, these tanks are pretty heavy and with the vibrations of the engine you easily get a stress crack ...

I hope my english is clear enough

cheers
KLaus

R68
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Joined: 08/20/2008
Posts: 457
Trivia...

....the 10cm bolt is for the standard tank, the 7cm bolt for sport and Hoske tanks..."Meier" sport tanks were marketed by Georg Meier aka "Schorch" after his riding days were over and he got the BMW dealership for Munich, I'd assume the most profitable BMW dealership in Germany? Incidentally, he had been Admiral Canaris's driver for a time during his Wehrmacht days, I'm told?...

paul25g
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Joined: 07/25/2012
Posts: 88
Hey guys, thanks for your

Hey guys, thanks for your help, I really appreciate it!

Found the following on Vech's parts site so looks like the 6.5 gallon tank did use a different bolt:

07 11 9 912 537--$2.50--hex bolt shanked front tank 6.5 gallon 8x1.25x70mm SS

Daves79x
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VBMWMO #9030
Joined: 08/09/2015
Posts: 325
You Can

If you are really looking for originality and don't want stainless, search for a right-side transmission-engine mount bolt and nut. Preferably with a 14mm head, which is correct for your bike. Then Dremmel off a few mm (can't remember, but it isn't much) to get to 70mm. Dress the bolt end to a factory look and have it plated - black is correct for your bike, but don't know if you are making any fasteners black.

Dave

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Dave

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