I am not shure a 4 stroke would produce more heat than a two stroke. Compression is higher and efficiency is better so for a given power output it ought produce less heat.

 

There might be dust or dirt or something that block the airstream through the radiator. A visual check would tell.

 

There are some strange cooling fluids around. I use battery water and 40% of anti freeze. No problem at all.

 

But, if the bike runs well I guess the most likely fault is the thermal switch.

 

And yes, the fan is quite noicy. Sometimes annoying.

 

Carl

Edited October 16, 201510 yr by carl ekblom

Carl, I wonder if you put some videos on the net where we could here your engine with  your factory titanium silencer?

Edited November 9, 201510 yr by levis

Well, I have to look into that. Meanwhile you can have a look at very good rider Martin Kroustek using the factory silencer. https://www.youtube.com/watch?v=VZEF_fHC8ho

Carl

Glad to find this thread!

 

I have a 2015 300 4t with supposedly 100 hours on it. I just got it, used. I live in San Diego, weather today is 79 F, 26 C.

 

Idle is inconsistent. Helps when I turn it up, but then it can get too high. Fan never comes off after the bike is warm, even when I coast downhill for 30 secs at 20 MPH with the clutch in. Radator is clean.

 

Not happy with how it idles, and with the fan always being on. It's pulling a lot of juice, which is think is exacerbating the problem - idle drops even more when i switch the lights on.

 

Based on my weather and riding 0-4000 ft above sea level, do you guys recommend raising the needle and tweaking the fuel screw? The guy I bought this from is a dealer, he rode the bike for a year and said it should be perfectly set up...

So here's a quick update - I backed out the mixture screw - no mean feat as it's under the front of the carb and almost impossible to reach - and the bike runs much better. Doesn't die when you snap the throttle open, and the fan actually did shut off at one point.

As far as the erratic idle - I took too much slack out of the throttle cable. When I turned the bars to the right, the cable moved and dialed in some throttle. Loosened it and she is better now.

I have a 2017 300 4t and the fan seems to want to stay on all the time once the engine is warmed up even when the outside temps are cool. I just checked the water pump impeller and it was good. The fan pulls a good amount of air through and back towards the engine. Is there any new news since the last post in 2015 on what could be wrong or what I could try to do to get the fan to cycle on and off? Or is this just been found to be normal?

I ran our 2013 & 2014 4t’s After washing down... after 10 mins sat at idle the fan would run for around 50-55secs then shut off for around 35-40 secs before switching on again... both bikes are similar on fan cycle times.