Problems with Temp sensor zx9r?

[maraach]

Hmmmm noticed something a bit odd on the zx9r today. The temp display seemed to be showing some pretty weird results. It warmed up as normal. Then i started riding it, and the display went back to "---" (warm up). A few seconds later it displayed 62, then went to 82, then went to "---" then came back at 92, and basically kept jumping between numbers (50, then 90, then 60...)

Anyone ever seen this before? Any idea what might be happening?

[jl4049]

loose wire or perhaps a chafe in the wiring from the sender?

[maraach]

hmmm sounds not too bad at least... as long as that is what it is. Guess i'll have to take it to the shop this weekend.

[maraach]

hmmm pulled off the side fairings tonight to look at the radiator fluid level. I dont think this was the problem as it wasnt low, in fact if anything it looks kind of high. Even on the side stand it was right up against the cap, but hey im not much of a bike mechanic so i dont know if this is a problem.

Also took a look at the switch which seems to have no issues. Guess i will have to try and trace the wiring through to see if i can find where the problem is. I have a feeling when i removed the front fairing and put it back on that perhaps some of the wiring is not sitting in the correct place and that there is pressue being applied to it which may be causing damage to the wiring. I sure hope not, but cant think of what else it could be.

[jl4049]

Could be that the sender itself is on it's way out too. If you have a multi meter you could measure the resistance across the sender when cold, then when hot, watch for a while when running and see if the reading jumps around, if so you've found the fault.

[maraach]

Thanks for the tip. Unfortunately i dont have a multi-metre but now might be the time to buy one i guess.

Just before heading out, i should just ask a question. I have never owned a bike with a digital temperature readout before and it has crossed my mind that perhaps this might be normal behaviour and i might be overreacting. I have gone over everything on the bike now that i thought it may be (checked the coolant reservoir level as well as had a look in the radiator itself). Checked all the wiring i could see to make sure i couldnt see any damage (which i couldn't).

Upon recommendation from the mechanic who serviced it i removed and looked at the temperature sensor switch (i believe this is the large plug located on the left hand side of the radiator - please correct me if i am wrong). It looks like a large 2 holes that sticks onto two prongs coming out of the radiator. After going for a brief test ride (which yielded pretty similar results) when i got home, just to test things out, i unplugged the sensor while watching the temperature guage. I honestly expected it to drop immediately to "---" (no reading) but instead it continued to move temperate around the 70 degree mark. Mainly it just dropped temperature every few seconds, however once it went back up. I guess i could be looking at the wrong thing. Any ideas?

[Rusty]

That's the thermo fan switch.

From memory the temp sensor's under the carbies on the left hand side. Single blue wire?

[maraach]

That's the thermo fan switch.

From memory the temp sensor's under the carbies on the left hand side. Single blue wire?

Thanks for that rusty. I should have known that was just the thermo switch, but seeing i couldnt see anything else i just assumed that the sensor was there as well. I had a look over the radiator again and the only single blue wire i can see is connected (looks like its soldered) to the back of the fan (with a black wire on the other side).

Im assuming this isnt the wire i am looking for. Am i in completely the wrong spot?

[Rusty]

No problem, mate.

The temp sensor's not on the radiator at all. It's on the rear of the engine below the carbies on the left hand side. You can see it if you look down between the tank and frame on the left hand side. The sender's above the coolant tube, and the wire should be pretty easy to spot. To test/remove it you'll need to take the tank off.

I just checked my F model, and it has definitely got a blue wire on it. There may be a trace colour on the E model (not sure) but the primary colour is blue according to my wiring diagram (which is slightly inaccurate).

[maraach]

Hmmm... i don't want to get overly excited yet, but it looks like the problem might be sorted!

Firstly went for another ride this morning, and although it appeared to work for the first 20 minutes, things only went downhill from there. On the way back 90% of the time the display was showing "---". This was enough to prompt me to give it one last shot.

Ironically (if it hopefully keeps working), it seems it was fixed in the whole of 15 - 20 mins. Taking the tank off was a pain, though everything else was pretty straight forwards.

It seems that the temp sensor in infact connected to a blue wire which connects into the back of the carb. I put some cr-26 on contacts of the wire, put everything back together and went for a ride. In the hour or so i was riding (in pretty bad traffic) the temp display never skipped a beat.

If anyone wants i took a picture of the wire and can post for future reference.