Uploading large files with Node.js and Restify fails

I have the following script that is supposed to receive uploaded images/videos and save them to disk. The script works for images up to 1.5Mb, above that size the file upload shows 0 bytes. There is lots of free space on the volume I'm saving to so free space is not an issue.

I'm making the request using SoapUI with a Media Type of image/jpeg.

http://127.0.0.1:8080/api/uploadfile/Test/cake.jpg

Why would smaller files work but larger files fail?

var restify = require('restify');
var fs = require('fs');


function uploadFile(req, res, next) {
    var path = req.params.devicename;
    var filename = req.params.filename;

    console.log("Upload file");
    var writeStream = fs.createWriteStream(path + "/" + filename);
    var r = req.pipe(writeStream);

    r.on("finish", function () {
            res.send(200,"Upload complete");
    });

    next();
}


var server = restify.createServer();

server.post('/api/uploadfile/:devicename/:filename', uploadFile);

server.listen(8080, function() {
  console.log('%s listening at %s', server.name, server.url);
});