I recently bought my first bike, a 2008 Ninja 250r, and had a question about overheating. Yesterday I took the bike to a parking lot with my supervisor and did low speed (5-25km/h) maneuvers for an hour or so. The temperature light came on near the end of our session and I could hear a boiling sound coming from the engine. My supervisor told me to take it up and down the road a few times at speed, which I did, and the light went off and everything was back to normal. Is this a regular occurrence and to be expected after long periods of low speed riding? Does the Ninja 250 rely on air cooling quite heavily? It was about 20-25 degrees Celsius outside and I was riding in the sun.

Thanks in advance,

-Mike

 

Did you happen to notice if the radiator fan was kicking on? Mine used to get warm at slow speeds in summer, but the cooling fan always prevented it from getting too hot. Make sure you're full of coolant and the fan is cycling. I found out after my initial valve adjustment (apparently they removed the radiator and didn't refill it all the way) that a small amount of missing coolant can cause overheat. After I filled it up to the top of the radiator, it stopped doing it.

 

Double checked my coolant today and it was very low ! I checked it when we went out as well but I guess I didn't get a very good look at it as it was quite a ways below the lower level line. I'm gonna fill it up and next time I ride I'll get back to you with the results.

 

No more overheating, everything works fine !

 

Congrats with the fix and ride safe.

 

Intro:
I have a 2004 Ninja EX250; and as a newbee, I crashed. The result of the crash, I had to replace minor parts: new headlight & housing, cluster bracket (holds the speedometer), and a stitched up upper fairing w/zipties. I've also noticed there was a bent prong thats connected/plugged into the radiator (see attached image); to fix it, i just bent back into shape and replug.


Problem:
Bike is now fixed up and started. Today's temp. is in the low 90's (farenheit), and went around a block placing it only on 1st gear and noticed that thermostat indicator was in the red area (overheat).
Pushed the bike back into the garage and checked for:
- Coolant level; which is the middle of low and full
- Hose; no signs of leakage
- Fan; works (kicking in)

Question:
All of the above is checked and OK. Asked a friend, he thinks its because of riding in 1st gear all around the block in a hot temp. and another say it might've been a glitch riding it for the first time since the crash.

I'm really not sure what it is or what to check anymore than what I've already done. Appreciate any help/feedback...

Thanks in advance!
Cassy

 

The bent prong is your thermostat. You may want to check to see at what tempreture your fan kicks on. (test that stat although you mentioned that you are not puking fluid hmm.)
You have mentioned replacing the instrument cluster bracket. Any chance of pinching a wire or having a bad connection when you put your gauges back in?

Welcome to KF

 

Thank you much for your response. What kind of a tool tester to use to test out what temp.? Rechecked assembled bracket, no signs of pinching wires. My next attempt is to just change out my coolant and air filter.

Thanks again for your advice.

Cassy

 

A pan of water on the stove to verify the rated snap disc tempreture makes at that tempreture and a simple ohm meter. But, you said that you are not overflowing. Which is kinda goofy if the stat is not operating or if the water pump impeller is bad kind of thing. Have you flushed the radiator system and added the proper glycol mixture? Then take it out on the open roads for testing. As mentioned, with the fan on and with not enough air circulation, your bike may ride in the red section. Good luck.

 

Yaay...it's fixed. I've flushed my coolant (thanks to Ninja 250 Riders Club http://faq.ninja250.org/wiki/How_do_...ling_system%3F) and changed my oil (alot of info from youtube.com). Overheated was looked at from a good friend from work and he also verified the whole function of the bike and made sure its ridable and brakes are fine; my slack adjustments are also fine. I started to ride on Sunday; and today for the 2nd time w/o anyone to follow me to see if I don't crash again
But also thanks to you too Dragon for your response.
Hope you have a great Labor weekend; have fun & ride safe!

Cassy