Originally Posted by pyoungbl
Hummm, my '10 model went from a quick start (like maybe 1 revolution of the crank) to totally dead; three times. I never had a time when the starter was working hard. That's not to discount the 'decompression lever' issue but the OEM batteries have been an issue for at least 10 years, the lever...not so long. Full disclosure: I have upgraded the ground wire from battery to engine case because that is a critical part of the electrical system and appeared to me to be too small.
Yes, agreed, the OEM battery is not the best. But those replacing it with a stronger battery should be aware that that stronger battery MAY be hiding an underlying issue that should get resolved, if in fact they are also experiencing the "hot start issue". Coincidentally my '08 KTM EXCR also has a known issue with a faulty decompression mechanism, that is on the cam. The '09 cam fixes this. I have not fixed this (yet), but am getting by for now with a better battery that has more oomph to get past compressed TDC. But kickstarting is very difficult--that is what your battery/starter is working against, and may be the reason an OEM battery degrades quicker--and then when you bring it into BMW they replace the battery because it tests bad.