Hey anyone out there who can help with the following?

Here is the scoop:

Bought a 2000 F4 with 27,XXX miles that used to be a track bike. Bought this as a commuter / learner bike. The CA emissions has been pulled off and the carburetor upgraded (to what, I don't know).
First time riding the bike (after purchase), got stuck in traffic for about 5 minutes. When I was finally able to move again the temperature gauge spiked to near red. I pulled over and let it cool down, and drove it home without incident. I then let it run in the driveway till it heated up again, couldn't get it to cool down so I did the following:

Changed the coolant (believe it was only water and water wetter for the track before)
Flushed the system (with an aluminum compatible flush)
Changed all o-rings in the system
Checked water pump
Cleaned hoses, radiator
Changed thermostat
Changed temperature switch for the fan

This is what is still happening:
Say I sit at a light for a few minutes. Upon takeoff the temperature spikes to somewhere near the red. (Note that prior to takeoff the temperature is about halfway and the fan is not running.) If I pull in the clutch and rev the engine, then the gauge may / or may not go back down to 3/4. Everything is intermitent and not consistent from day to day. Sometimes I can't get it out of the red until I pull over, shut down, and let it cool.

I thought I might have a leak in the radiator that is sucking in air and creating a bubble. Sometimes I smell coolant, but a local shop told me that this is more likely the overfill, which makes sense. The radiator is hot and at high pressure so it wouldn't suck in air while running, but it could while cooling and put a bubble in the system.

The local shop told me that these "modern" sport bikes just run hot. But come on, the temperature gauge in the red, not likely!!! I asked if they could pressure test the system and they said that they just run bikes to pressure and look for the leak.

Any thoughts, input, etc would be much appreciated.

I don't think it is the temp gauge itself, because the fan always turns on at about 3/4 of the gauge and the fan runs off an independent temp sensor/switch near the radiator, while the gauge temp sensor is near the thermostat.
How about installing a bypass switch for the fan? Is this common? Would this help?

 

I've had the same types of problems... the fan even killed the battery in traffic once and Ihad to bump start every time I hit a red light or rev it to keep it over 3000 (the stall point - with a D&D in traffic you just bump start, or someone will get really mad and do something stupid).

I flushed the coolant - cleaned the radiator - and split lanes when I can.

 

Well on the F4's the fuse for the fan likes to blow. Check the fuse and that will help alittle, but mine also gets hot if stuck in traffic. I wouldnt pull over and wait for it to cool down unless you are still in traffic, but if you have some open road where you can drive alittle then drive because when moving the air cools the bike fast. But its normal for me, if Im in traffic.

 

mine rarely spikes very high, but then im in cali and "traffic" doesnt often apply. However, 100+ degree days do, and it always seems to stay pretty cool...relatively speaking of course.

 

So it only spikes into the red right when you take off after sitting in traffic?Does the needle on the gauge jump up really fast or does it kinda creep up?If the needle jumps to the red really fast on the gauge it might be the wire to the sending unit have a bare metal spot somewhere and grounding out on a metal surface.I have had that happen in a car before.Also is it losing coolant at all?

 

I had similar problem with my zx1000 before I was converted over to honda it was supposed to happen to these bikes often, alot of folks installed manual switches for the fan which is what I did. and it worked in keeping the temp down when in traffic after riding on the freeway.But it's only a band-aid and not actually fixing the problem.
one other suggestions might be to check your radiator cap. sounds too simple but if the cap wont hold the proper pressure the boiling point in the radiator can be reduced causing it toover heat. good luck andkeep us posted please.

 

Have a look at the inspection hole at the bottom of the water pump. If you see any coolant, the pump needs replacing, there are no servicable parts available. Same symptoms happend to me, replaced the pump, because there was a drop from the inspection hole, and now she runs great. Hot days sitting intraffic she doesn't go past 3/4 guage. Just something else to check.

 

check the fan shroud....f4s are known to have th fan get hung up on it and over het and often blowing the fuse.

 

So 3/4 in traffic is normal? Mine will go there too, i always thought it was supposed to stay in the middle like a car.