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Old 01-19-2011, 03:18 PM   #24
JRWooden
Beastly Adventurer
 
Joined: Jul 2008
Location: The great state of confusion
Oddometer: 4,101
Quote:
Originally Posted by The Griz View Post
I don't know about that, man. Mine's cracked twice now. Once with the charcoal canister installed and once without it installed. My opinion is that the charcoal canister has nothing to do with it. It's just shotty plastic molding: horribly formulated plastic and too thin.
Griz:
Did you read the fine print in the poll
Have you removed your pressure check-valve? If so that would be an interesting piece of information!

I'm not asserting its the CANISTER it's self, but the canister "system".
The canister system has a checkvalve in it that allows the fuel tank to build ~5psi of positive pressure. The rest of the world's F800GS never build any significant pressure. I think this is a key factor. (I could be wrong...)

EnderTheX & Griz:

I am a mechanical/mfg engineer as well.
I do not dispute any of your assertions (well at least I don't think I do )

I do think the radius is too sharp, and that over time the non-USA bikes might crack as well. Some folks with the new Rev #2 tank (more gentle radius) have had tanks crack as well.

Materials selection, wall thickness, wall thickness transitions, location of mold injection ports/knit lines, and ... maybe process problems ???

Along the crack line of my tank there appear to be some small bubbles which might lead me to beleive injection temperatures were too high, perhaps there was too much moisture in material, or the cooling rates were non-uniform.

I'm not saying the ONLY factor is the pressure checkvalve in the canister system I'm just saying its an aggravating factor.

The reason I haven't had mine replaced is that it just doesn't piss me off that badly ... I think (hope) that BMW has called in some experts in plastic molding process by now and is working on Rev. #3 of the tank - so I intend to wait till near the end of my 3-yr warranty and get a new tank then ... hopefully it will be rev #3 if not than I'll have 2-yr extension on the warranty and by then have a rev #3 tank.

Maybe I'm just talking out my a$$...
It's happened before...
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