For a long bike ride or run in the morning I'll cut my basal dose back by half, and will only have one unit novorapid with breakfast.
I'll then eat/drink about 60g carb per hour, a bit less for running, adn at the following meal will again have a lower novorapid dose by about 50%.
When I say long ride I'm talking 2hrs plus, long run is 90 mins plus.
I'll typically test every 45 minutes while doing it.
I haven't tried long runs/rides in the afternoon/evening yet.
Exercise makes you more insulin sensitive, so you need to cut back rather than inject more. Have you read Think Like a Pancreas, or the ADA's Handbook of Exercise in Diabetes? Both worthwhile