GoodDay All.

I'm after some better cooling for my 07 KLX250s. I see some aluminium rads on Aliepress. They won't tell me any dimensions.
Any good feedback appreciated.

BeWell; M

 

I think you're wasting your time and money. The KLX has as much radiator area as a KLR. I have never read about nor heard of any overheating problem due to lack of radiator surface area. The only time I've heard of it is if someone's fan has failed to work and I'm not so sure it's even a problem then. The KLX300 has been running the same set up, possibly without a fan, for about 20 years. I did install a Thermo-Bob which remedies a flaw in the cooling system that may or may not cause problems.

The OEM thermostat positioning will stop all flow around the cylinder when closed. That will create a hot spot in the upper area around the top of the cylinder and head since not only are those the hottest areas, but the flow of hotter fluids goes to the top. The Thermo Bob moves the thermostat to allow a flow line around the cylinder when the thermostat is closed, creating a more uniform temperature around the cylinder/head.

There was actually a fitting blocked off on the engine on some years for sure, that allowed the same bypass to be made to allow flow. I am not sure if it is in this forum or the ADVrider forum. They treaded in a fitting and plumbed in a tee in a coolant line allowing the flow. Do some research using Thermo Bob in this forum and see if it comes up.

 

KLX687.
Thanks for your opinion. Much appreciated.

Now ; Anyone have an answer to my question? I ride in some very harsh conditions. Where I'd need two or three fans to get any useful cooling. And on my KLX only one rad fan will fit. The answer .... Bigger more efficient radiators.

The illustrated parts list I am using doesn't show a thermostat or its housing. Perhaps someone will enlighten me.
Aww. I see on other posts left side up on the cylinder w/hose straight outa the bottom of the left rad.

Yep... THERMOBOB looks like a great way to go. Thanks again KLX678

Any other useful responses will be rewarded.

BeWell All; M

 

You riding on Mercury or something...

You could get a KLX650 left side radiator and fit it up. It is significantly longer with more cooling fin area, Right side is about same size as the 250. Otherwise you will end up having to get custom radiators built.

What has factually convinced you you need more cooling? You'd think if there was a problem there would actually be options out there. Just hasn't happened in over 25 years of KLX250/300 production. I know there some members here riding the southwest desert areas and some riding in some pretty hot areas in Australia without issue. Seems like a lot of money to spend on what is very likely a non-issue.

Per the KLX250 shop manual:In other words unless the fan is on the coolant temp is below 208°F/98°C. Unless your fan is running near constant your temp is fine.

I guess will leave it up to others to tell where they ride in high temps without issue. About the only thing I've seen done, in the near 12years I've been on this forum, would be putting a manual switch on the fan, but if I did that I'd be sure to run it in parallel to the sensor circuit should I forget to turn on the switch.

 

KLX678
Thanks again for your courteous and prompt reply .
Not quite Mercury. But something similar. Stop and go, emphasis on stop, traffic.
When ambient air temp can be above 110F and reflected black asphalt heat is added.
So, though you might not know my situations hyperbole is almost always unproductive.
The stats are interesting but unless I put a temp gauge on my ThermoBob I'll never know the real temps.

No-one else?
Oh well. I'll shoot the moon on 105.00 USD aluminium rads from China. They say in their write-up that they will fit.
And I'll update this post.

BeWell Every. Yours sincerely; M

 

Okay tried to give some guidance on the issue and say try it and see if the fan runs all the time, but you choice. If I was really concerned the first thing I'd do is install a water temp gauge on the bike and see if it really is a need before spending hundreds. Here is the Trail Tech gauge

Click here

Click here

 

Please delete.

 

GOOD IDEA. I CAN'T UNDERSTAND WHY KLX CAN'T UNDERSTAND... HEAT KILLS
BeWell; M

 

They do understand, that's why there are two radiators instead of one like some bikes, like the CRF250L. Not sure of it, but by the parts schematic looks like the Yamaha WR250 also only uses one, but a bit longer.

Don't take my comments as a big negative about what you want to do, take them as trying to give you some thoughts on how to make sure you need to change things up, saving you some money.

You could get another fan and mount it to the other side by making some tabs to fit it and hook it into the right side electrics. Plus the KLX650 left side radiator. If you could fit one up you could see if you could get another one modified to work on the right side too,.if the exhaust allowed it.

Keep us informed on what you end up doing. It may help others too.

 

I had considered this as an option. I have only had my little red overheat light come on once, chugging up a steep rutted road very slowly with 2 kids and wife going super slowly. but it still made me think of trying to get a second fan mounted upon the left side, operated manually perhaps.....