The Grand Union, which is at Great Western Road right near the Westbourne Park tube station, is a good pub and they have some tables and chairs canalside in good weather.
The Waterway in Maida Vale is a bit upscale but has a great outdoor deck right on the canal and is never too crowded.
There's also the Cafe Laville, which is on Edgware Road in Maida Vale just past Little Venice and is literally over the canal where it runs through a tunnel for a bit before popping up closer to Regent's Park. As the name suggests, it's a cafe and not a pub, but they do serve beer and it's bike friendly. They have an outdoor patio thing over the water.
Going a bit farther east, there's the Constitution in Camden, which is a proper old boozer with a great outdoor garden on the canal.
There are some pop-up places along the way that cater to cyclists in good weather, with coffees and beers and where you can fix a flat or lube your chain (!?).
Last on my list is Broadway Market in Hackney, where on one side of the canal there's a place called Lock 7, which is a little coffee shop/bike repair shop and north of the canal are a few good pubs, restaurants and shops, including F. Cooke, which is one of the few remaining old-school eel, pie and mash places in London and if I recall correctly, the proprietor is Spurs!
All best on a weekday when it's not so crowded, especially on a bike.