fifa4champ. The bonk is not a nice feeling. One trial is usually not enough to determine if something is broken. It may have been that you were drained before you even started the ride. I suggest simply that you make sure you are fueled before starting and do the 2 EFS liquid shots again for a 4 hour ride. Please let us know how it goes.
from my personal experiance using LS, I go thru one per 70-80 mins. On a 3.5 hr ride last week I finished almost 3. I buy the jug and put it into a small water bottle, easy for me. And I make sure i have enough water to chase it with. 2 LS flasks for me (small guy 147 5'8) isnt enough, most people need around 300 cal per hour 800 cal for 4 is 200 per hr, for me that would be a bonk.. Could through in a EFS bar, may work. I am not qualified in any means, but I have experimented alot. Good luck!
One thing is to identify your caloric needs based on variety of factors. Body weight is good place to start. I know I need 250 calories per hour to keep energy level up based on my body weight. So for a 4 hour ride I would need ~1000 calories. Believe the EFS flask is 400 calories per.
Therefore in theory should consume 2.5 flasks for a 4 hour ride.
Can tell you this nutrition strategy worked perfectly for IM Arizona in April 2008. Sipped shot every 15 minutes followed by a sip of water. Marked the flask to insure I took suffecient amount in.
Hope this helps
How much one EFS liquid shot weights ?