Originally Posted by tmotten
As much as I'm enjoying seeing the results of this test I can't help but think that it's a bit circumstantial because of the duration of exposure to the fluids.
I had similar thoughts. The volatility of things like gasoline and carb cleaner, particularly carb cleaner, means that if they were merely sprayed on (as might be the case when chain cleaning) they would evaporate rather quickly. Given the correspondingly short duration of exposure they would likely exhibit much less impact on the o-rings, versus soaking in the fluids overnight.
That said, I still want to applaud your undertaking a rational scientific method, instead of the typical, "well, I've always done it this way with no problems".
I agree with one other poster also, I thought the main point of concern with WD-40 had less to do with its direct impact on the o-rings and more to do with its getting past the o-rings. How that is possible, beats me? Just something I read on a web forum once.
(edit: FWIW, I found where I read about WD-40 being a problem, towards the bottom of page: http://www.webbikeworld.com/t2/motorcycle-chain-lube/
it may not be relevant, but might be of interest)
Keep up the good fight.