The key is being social, as Dan says.
That means - watch, and comment on, other motovloggers channels. Eventually your name will appear familiar to people and they will check you out. I did this for 6 months before I uploaded my first vlog...
This is where it pays off - these channels will be curious to check you out - because you aren't someone who just popped up out of the blue and asked them to watch your stuff. ONLY THEN will their greater audience even notice you.
There is no short cut to this, I have seen people appear out of nowhere and literally DEMAND attention, and even start merchandising, but because they didn't watch and comment on other people's vids nobody knew who the hell they were and it simply didn't work.
Another reward is you will form great relationships with motovloggers around the world. And not just on-line - I have met and rode with 25 motovloggers and I live pretty remote. But when I've travelled, they were keen to come and meet me because we already "knew" each other. It's the best bit of the whole thing for me

Another hint I can give you starting out -
Put something in the "About" tab on your YouTube channel. Even if it's just what bike and camera you use, where you ride... you know - something is better than nothing and you can always update it. I know many of my fellow vloggers who will check a channel out and are more likely to look right into it if there is a description.
Lastly - put a link to your channel in your signature here

Now for your vlogs - do test runs and make sure the sound is ok. It can take many attempts to find the right position for your mic. Even if you are not talking, use an external mic - NOT the camera's built in one, no one likes to hear the crackly shit that the wind makes in the in-built mic when you ride!
Good luck, hope you have as much fun as I do at this!!