I assume a gen 1 and gen 2 are relatively similar. All I did was pull both left and right fairings so I could get to the water pump on the left side and the coolant tank supply on the right side. I disconnected the hose clamp to the water pump outlet and drained all the old antifreeze into a pan. I have some empty plastic 5 gal. drinking water (reverse osmosis) bottles and filled one bottle at our local health food store to flush out all the old antifreeze that remained in the system. I filled, circulated, drained, over and over until the water exiting the water pump was clear. I then drained all the clean water, added enough straight antifreeze to get 50% antifreeze volume according to the owners manual, and then topped off the coolant tank to the high level mark with more reverse osmosis water. I believe I also changed the hose clamps to the stainless worm gear type and made sure they were tight. I don't believe there is anything special about the brand of antifreeze you use as long as it is compatible with aluminum. I used Prestone brand that was supposed to be a long lasting type ( supposedly 5 years until having to be changed again). On the last circulation of coolant after I had added to the high level mark, I rocked the bike to the left and right to try to get any air pockets out of the system. I must have been successful, as the level has never changed and I have had 0 issues of overheating. It's not difficult at all, just a little time consuming.