Do I need a fan?

farmerj · #1 08-01-2023, 11:13 PM

2nd post of the day…

Twice I?ve researched ?how hot is too hot for the water temperature of a two stroke dirt bike?. And while there are lots of people asking the question, I can?t find a definitive answer.

Today on the tight single track I was running 200 to 231F. Is that too hot? I?m using engine ice, and didn?t lose any fluid. But I wonder if I need a fan?

Thanks for your thoughts.

Jacob 'Berg · #2 08-02-2023, 11:53 AM

This is probably not the response you are looking for, but if the riding you are doing causes the bike to boil over with a 1.8 bar cap, you need a fan.

swazi_matt · #3 08-02-2023, 03:04 PM

that sounds about normal. the older bikes had a 1.4 Bar cap which would boil water at about 230F . The older configuration did have the radiators more exposed to air flow than the 18s though. 1.8 bar would boil water at 242F (engine ice and other coolants boil at a higher temp)

I would say get a fan if you ride terrain that results in bike boiling. the engine temp spikes considerably when it starts to boil, so if you boil once on your regular terain then fit a fan

Moto7man · #4 08-02-2023, 05:10 PM

Yes, get a fan. I have had one on my 2011 EC 300 since 2012 and I just put a fan on my Ranger 300. I set the thermostat for 205F to 210F and it works well. The tighter the terrain in muggy humid weather the more you need to have a fan option. I live about 90 miles from Sequatchie TN and they are having the Tennessee Knockout on August 18-20. I can guarantee that all the pros and amateurs are using a fan.

SS109 · #5 08-02-2023, 08:08 PM

I never have felt the need for one even when riding hike-a-bike terrain as my Gasser has never boiled over and I even have a Rekluse. If you have issues with boil over then I would say, yes, get one. Otherwise your just wasting money, time, and could potentially drain the battery to where the e-start won't work.

Just this man's opinion!

Moto7man · #6 08-02-2023, 10:40 PM

Quote:

Originally Posted by SS109

I never have felt the need for one even when riding hike-a-bike terrain as my Gasser has never boiled over and I even have a Rekluse. If you have issues with boil over then I would say, yes, get one. Otherwise your just wasting money, time, and could potentially drain the battery to where the e-start won't work.

Just this man's opinion!

I agree it depends on how and where you ride. I ride really tight woods with very sudden elevation changes at a relative slow speeds and it is super humid. I have a temp warning light on my voyager pro and when I come into a tight,steep uphill climb with swichbacks, I will flip on my manual fan switch on the bars to get ahead of the curve.

From seeing your videos in Arizona with the pace and terrain and the lack of humidity, I can see why you would never need one.Btw, I really like your videos,thx for posting.

farmerj · #7 08-02-2023, 11:13 PM

Great ? good info. - for me the bottom line is probably ?better safe than sorry?.

But this leads me to another question. I am not currently having a problem with boil over, and with engine ice the temperature could conceivably go up quite high. I thought the problem with high temperatures was seizing?at what point does that become an issue?

farmerj · #8 08-02-2023, 11:14 PM

?and why does my punctuation turn into question marks???!

Moto7man · #9 08-03-2023, 12:33 AM

Quote:

Originally Posted by farmerj

Great ? good info. - for me the bottom line is probably ?better safe than sorry?.

But this leads me to another question. I am not currently having a problem with boil over, and with engine ice the temperature could conceivably go up quite high. I thought the problem with high temperatures was seizing?at what point does that become an issue?

I think engine ice and a high radiator cap rating could raise the boil over point higher. I rode with ktm people using engine ice and no fan and they had boil overs at 255-260 but I don't know if that is typical. I don't know at what point image damage would occur, so I will let else chime in on that. For me, I would like to keep my bike at 235 or so max.

I had a buddy with a Beta 430, he didn't have a fan but he had an overflow bottle. His bike would get hot and we would take a break and we could hear the coolant being sucked into the rad as it cooled.(and on that Beta the gasoline in the fuel tank would boil, no kidding until everything cooled down).And he never had an engine problem,go figure

SS109 · #10 08-03-2023, 01:45 AM

Quote:

Originally Posted by Moto7man

From seeing your videos in Arizona with the pace and terrain and the lack of humidity, I can see why you would never need one.Btw, I really like your videos,thx for posting.

Thanks!

Yeah, we normally keep a decent pace unless riding the super technical stuff and we only do that in the winter (45-70F) here as the heat will kill ya. It is kind of funny when I hear my buddies' KTM's fans all running (some with Engine Ice) when we take a short break yet my KDX or Gasser are fine without and running standard 50/50 coolant!