To some extent, yes--they might hassle you a little bit if they are having a bad day, but they will not refuse you entry for no valid reason. I have exited/entered Russia probably about twenty times now and the Russian borders guards have ALWAYS been very professional. And if what you say is true, it would be true regardless of what type of visa you have...

Maybe they guy was having a bad day, maybe there were issues with someone's visa. There does not seem to be any indication that the "problem" (if you can call it that) was cause by having the wrong kind of visa.

With Turkey, it is a different and far more serious matter, because of the recent breakdown in relations between Turkey and Russia; currently Turks are often not allowed into Russia regardless of the type of visa they have (previously they did not need a visa). But this is directed from the top, not at the whim of individual border agents. So if your country shoots down a Russian jet, etc., it is true that you could face problems entering Russia, even if you have a valid visa. But for instance, as a US citizen I've had no problem entering or exiting Russia many times over the last couple of years.

I disagree that it is the "wrong" type of visa for motorcycle travelling. I have a three year Russian business visa--are you suggesting that during that period I cannot come here on personal business? Frankly it does not make sense. Moreover, the website of the Russian embassy in the US does not say anything at all about business visas being solely for "business" purposes; the only difference between the visa types seems to be who does the invitation (a business, a private individual, a cultural institution, etc.).

While it is certainly possible in a theoretical sense that business visas might cause moto travellers problems at the borders, I think we should focus on whether anyone has had an actual problem rather than hypothesizing about what could happen.

And as mrsroynie points out, whatever kind of visa you get, you should be careful about choosing your visa agent and how you fill out the application.