I was reading the bushwacking / overheating post about the new trail ride and overheating with the aftermarket fans. I didnt want to hijack the post so I thought I would start a new thread. my klx250s is 100% stock so far and as of yet I Have Not Seen my cooling fan come on at all, Ever. I havent been riding the bike for hours on end but have been riding it about about a hour or so at a time. Is This Normal, the fan not coming on Or does it just come on once the motor gets real hot. Inquiring minds want to know.


LV

 

hey, i got all the mods done, but i have done nothing with the tank/ fans.. so that part is stock, i have 3,000 miles on my bike and mine have never come on either, even sitting in traffic in 90 degree weather, i would think they would come on when you are at high rpms but not moving real fast... i havent done much of that...

 

I had almost 2200 miles on and mine finally came on on a really technical trail, going in first gear on a grade, and no wind. I was happy to hear it come on, trust me on a hot day in first gear, and going really slow it will come on.

 

Thanks for the info guys, good to know. For a while I was wondering if it even works. Sounds like I just havent got the motor hot enough to use it yet.


LV

 

mi9ne was runnin for the first time yesterday. really hot and slow nasty trails. trust me when that fan fires up youll know it, not somethin youll need to see runnin to know it is. the exhaust'd hot air from the radiator is pushed out the side of the plastics directly onto your legs!! [:@]

 

Mine ran quite a bit this past weekend. We were riding in thick timber with no breeze and about 98 degrees. If you think about it all of your water cooled MX bikes don't even have fans, they depend soley on the air passing over the radiator to keep them cool. Ofcoarse they are usually running faster on the track that we are in trails, and for shorter periods of time. So don't get too excited about the fan not coming on...... it will when you need it to.

 

Mine comes on almost every time I have to move cows. Its a lot of first gear slow riding, and at most high revs in first gear to chase that one dumb-bastard-calf that wants to go the wrong way.

I wonder if a rejet to run it a little richer would bring down the temps some, at least enough to not need the fan.

 

Most everybody else's experience mirrors mine in that the fan never comes on unless you are 1) really working the engine, and 2) going very very slow. If you are going fast enough to be in 2nd gear, there is plenty enough air flow such that the fan will never turn on. Even in first, if you are at least moving forward a few MPH, then the fan will nearly always be off. Understand that I was riding in thick woods with downed trees, spinning over said logs, getting tangled up in vines and briars, working my way around thickets too dense to go through, inching forward at a snails pace, and in 100 F + temperatures in the shade with no breeze. As soon as I made the connection to the quad trail at the end of the segment and got some better forward motion, the coolant temp dropped by at least 20 degrees and the fans kicked off. I would be surprised if the stock fan kept the bike's over temp light from coming on in those conditions even if my replacement fans don't quite match up to the stock fan's air flow. That was some pretty harsh riding in pretty much worst case conditions. Note also that I've got a 300cc bore kit installed. I don't know if that makes any additional heat or not over the 250. I'd say it probably does, but I'm just guessing. Even so, I added a second pair of fans and they did better of course since that doubles the air flow that I had.

But I'm not at all worried about it. That's the first time the over temp light has come on and I've had the bike for over six months. But if it does it again, the solution is simple - just stop and take a break.

 

The only time my fans come on is when I am climbing a long, steep, trail, in 1st gear around 6500 rpm or riding in sand. You have to really put a load on the bike to get the fans to come on, mine have never come on riding on flat ground or commuting.