After the first couple of sessions at the track, when I got back to the pits coolant pissed out and then I noticed that the temp gauge was flashing HI. At first I thought it might just be an air pocket from not bleeding the system properly when I swapped out the coolant for Water Wetter so I ran it without the radiator cap on for a while (once it had cooled down obviously) and kept topping it up. Sadly it still kept overheating after only a few laps and I noticed that the fan wasn’t coming on.
I couldn’t do any more at the track so at home the next day I had a closer look. I found that someone had installed a second fan on the radiator with a manual switch but it wasn’t connected to power. It shouldn’t need any fans while it’s moving and Lonny, the guy I went to the track with had a 2004 ZX6R that had the fan deleted and his ran hot but didn’t overheat. So I removed the second fan and cleaned the connections on the stock fan wires and that was all it took for it to start working. I disconnected the radiator hoses and flushed it with the hose pipe, checked that there were no major blockages in the air fins and buttoned it all back up. I warmed it up to see that the fan came on and then when I ran it up and down the street the temp started coming down so I’m hoping that it’s sorted.
While tinkering with the cooling I noticed oil dripping from this bolt.
It turns out that this is one of the main crankcase bolts that clamps the crankshaft bearings on either side of the con rods. I started tearing into the engine to install a heli-coil in the upper engine case and got down to the throttle body. Then I had to pop to TSR to get a bolt that had rounded on one of the clip-ons and Denny suggested trying a longer bolt in the crankcase to get me through the end of the season and found one for me. There’s only one more track day this season so I decided to give it a shot. I installed the bolt in the hole until it bottomed out and it was a touch too long so I found a suitable washer to use as a spacer and bolted it back up. Haven’t seen any more oil leaking on the few test runs.