I'd agree with Eran there. After all, Paul had an awful lot to say about the role of Christ in salvation, but Jesus himself didn't. Yet it would seem odd to suggest that an authentically Christian view is one that ignores half of the New Testament. After all, a Christian isn't simply someone who follows Christ; it is someone who thinks that Jesus was the Christ, and that is a belief which cannot be certainly ascribed to Jesus himself. Even if he did believe it, it certainly wasn't the centrepiece of his teaching. So why base the name of the religion itself upon the title? Because the religion isn't simply about his teaching.
A post-biblical example of this sort of thing is abortion, which neither Jesus nor Paul mentioned, but which the early church unanimously opposed. Was that opposition unchristian because it concerned an issue not mentioned by Jesus?
Firstly, I don't think I'm entirely disagreeing with this point. I agree that Christianity naturally evolves into more than what Christ taught, and definitely includes one's perspective of who Christ is.
I also would maintain that Christianity has to develop in response to the social, economic, and political realities of the time. I'm not suggesting that Christianity isn't pure unless it sticks to Christ's teachings - I'm most certainly not saying that it is 'unchristian' to worry about issues that Jesus didn't speak of.
I'm simply suggesting instead that those issues are not the prerequisit to Christianity that some might claim. There was, and is, significant diversity on what makes one Christian and on which scriptures to accept or reject in the form of canon.
To use your example here, abortion is one of those issues not central to the Biblical message but over time has had a biblical commentary added to it - a perfect example of culture and political reality informing and shaping a particular interpretation of Christianity. One should not claim to be any more or less Christian on the basis of their stance on abortion any more than their ownership of a computer. Their Christianity might influence their perspective, but is not dependent upon it.
I'd most definitely dispute the fact that Jesus had little to say about salvation, however. The mode of salvation he talks about may differ significantly in the gospels to Paul, and to subsequent interpretations of Paul. I'd suggest Christianity post-Luther has come to particularly appreciate a Pauline reading of salvation (ie, focusing on the means and purpose of salvation by grace over law) - while other modes and descriptions of salvation have been neglected. Salvation here should be taken in the full Greek sense of the term surrounding saving - sotor/soter/soteros. Christ came to promote and encourage physical, social, and communal restoration as much as any eschatological purpose. The gospel of Luke covers this concept extensively, and the other synoptics also touch upon it.
John's mode of salvation differs, but is clearly there... even if the specific language of salvation doesn't appear.
I think one's view of salvation can differ significantly depending on which book they read the Bible through... Luke, John, and Romans can all lead to vastly different soteriological understandings.