Chinese radiators

[kdxdazz]

Looking at buying a set of radiators for my Kdx220, some are double the price of others, I wrote to the sellers asking what the difference is between their radiators and ones half the price, not one seller could answer the question, here in Australia it's common for sellers to rebrand Chinese things with a tuff sounding name then double the price, anybody know if all the aftermarket radiators are the same or are some better than others?

[PacificNWRider]

I have been wondering the same thing. There is some really nice looking sets on ebay from China, and they look well made with good welds that mirror the nice aftermarket ones I see for sell in the states. As far as I can tell these days most products are made in the same factory but just go through different levels of quality control and re-branding. Usually China just copies the product since the cheap bastards want everything made for pennies, and they send virtually every product there to be made. China says OK and then they sell them with some off brand or no brand for the same price they sell them to the companies for....

Would definitely be curious to see if anyone has bought / run them. Don't really see how they could be made any cheaper, maybe they have a weld or two somewhere that didnt pass the QC check? I'm close to pulling the trigger because they look so nice.

[kdxdazz]

Reason I'm asking is I have a Chinese set on my bike already, the bike constantly overheats, I've already pulled the tanks off and run a hacksaw blade through the cores to make sure they are clean, just don't want to buy another set and they don't work

[PacificNWRider]

Well interesting, sorry to hear they are not working for you. Have you pressure tested the system, are you sure the radiator design itself is the problem? Any chance the bike is running hot from something else?

Sorry to throw questions at you, want to make sure you are heading the right direction.

Radiator is pretty simple in its design, usually if they aren't plugged or leaking they will cool....I have a $20 china radiator on my wifes new honda car, I know a different animal, but they are simple in design, even the cheap ones will work if they are flowing and holding pressure with the right mix of antifreeze, however never heard any feedback on the dirt bike ones.

[kdxdazz]

Pressure testing the system would only indicate a leak, water pump rebuilt and impeller replaced, running rich so should be running cooler, I don't think radiator design is as simple as you think, the amount of cores and fins looks different from OEM to Chinese radiators, obviously tank design is just to hold water, I live in the north of Thailand and most days we ride is over 30 degrees Celsius, I just picked up 2 noctua ppc computer fans to aid in cooling, but back to the price difference, I have no problem paying twice the price for radiators that are twice as good, I wrote to a couple more sellers asking for the differences between there radiators and other radiators at half the price and they still didn't know, something smells fishy to me

[PacificNWRider]

Yes it would indicate a leak which could be small and not easy to see, that would cause the system to not hold pressure which is what aids in lowering boiling temps = not overheating.

I have worked on radiators from engines from 1910 - 2015, so I suppose complication is a perspective.
Its possible the walls are too thick, and if they have less cores / tubes / fins then it would be that much percentage less in efficiency, I would guess around +/- 10%.

You can pretty much ignore any of this If you are riding technical trails at 15 MPH or less then that is why its most likely over heating. Doesn't matter how nice or expensive the radiator is it will not cool without airflow. Fans are pretty much a must in that situation as well as a water wetter type product. I also use Noctua fans.

If your not riding slow then there are a few things that could be the problem besides the radiators.

Did you make sure the water pump impeller is spinning? Timing, worn reeds (excess air at mid - high range) could aid in over heating.

Also when you say you are running rich do you mean jetting fuel wise? (correct) however if you are running say a 50:1 mix, dropping to a 40:1 mix would most likely help the engine run cooler.

As far as the sellers not answering you, it is because most likely noone knows anything about the products they sell anymore, specially technical type questions like what you are wanting to know. I feel your pain.

I forgot to mention, If you are sure its the radiators, have you tried to find a good set used OEM? The reason I say, only ones I can probably say are known to be good radiators, without feedback from other aftermarket units

[kdxdazz]

32:1 oil ratio, OEM radiators don't exist in Australia, in fact there are only a few kdx's for sale in the whole of Australia, I will have to. Just buy the Chinese radiators as there is really no other option, I looked at modifying some other model of OEM radiator but nothing comes close, my bike overheats even just riding around on the street, when I first bought it, 80 percent of the cores were blocked with dirt and the entry to the cores were folded over by the aluminium, very strange, I cut the tanks of and ran a hack saw blade through all the cores, it greatly improved the overheating problem but not enough, when the bike gets hot it starts to run so rich it won't idle, just did a recent top end rebuild so not wanting to destroy my piston anytime soon

[KDXGarage]

kdxdazz, PLEASE make a signature that states you have a non-USA model. Time after time, you ask for help, then someone stops to take take time out to try to help you. Within a few posts, you magically reveal that their ideas won't work on YOUR specific KDX. SURPRISE! Once again, you have wasted their time and yours. Sorry to type all that, but it happens the majority of your posts. Thank you.

[kdxdazz]

kdxdazz, PLEASE make a signature that states you have a non-USA model. Time after time, you ask for help, then someone stops to take take time out to try to help you. Within a few posts, you magically reveal that their ideas won't work on YOUR specific KDX. SURPRISE! Once again, you have wasted their time and yours. Sorry to type all that, but it happens the majority of your posts. Thank you.

OK I will try to learn how to do that but can you be more specific about your response, my bike is a KDX220, it's the SR version, but what does that have to do with Chinese radiators? What ideas were given to me that won't work on my specific kdx?

[bufftester]

IIRC a few months back you posted about cooling issues and having Chinese radiators with only 9 or 11 cores or something. Seems I remember the pic you had showed a radiator with a lot of airflow blocked by some shrouds or something and fairly large fin spacing. You mentioned that you had run a hacksaw blade through the cores, but that doesn't mean you got everything out. Many folks then suggested making sure your coolant flow rate is good and then trying different radiators. I have spent a lot of time riding my KDX in the Florida woods when the temp was 35C+ slogging through mud and sand and never had it overheat. If you can't make it two blocks you have something wrong in your system. There's the pump, the radiators, a bunch of hoses, and the cooling jacket in the engine. Hoses easy to check. Radiators can be flow checked. Have you checked flow through your cylinder head? You had mentioned the radiator being full of dirt or something initially, but no mention of flushing the system out.

[KDXGarage]

On the Impex site, it shows the radiators are the same as the 1995 / 1996 black USA radiators. Your pic a few months ago looked like some half-sized silver radiator.

Can you post pics of the current radiators? Yes, you are in AUS, bike is in Thailand, but maybe you have some on your phone??

[Kdxfan4130]

52234CDA-8177-4786-A391-3A85B65D4755.jpeg (224.32 KiB) Viewed 3371 times

These guys are in the usa but Mylers motorcycleradiators dot com can rebuild your factory radiators and reinforce them to better than new. They pressure check their work, they also have a kdx200 95-06 cap side radiator for sale currently in their close out section right now. They specialize in aluminum radiators. The website has pics of the work they do, rather than buy a Chinese radiator with fewer veins check into the repair section on the site. I have oversized Mylers radiators on my Honda and have no issues boiling over.

[PacificNWRider]

I didn't realize there was more to the story here. That makes more sense with your location / model. I am Just trying to help. There is definitely something going on if you are overheating that fast... that's about as fast as riding with none/empty radiators! Half sized units probably aren't going to cut it in Thailand, maybe Alaska...;) Even if they were half sized you would think it would provide SOME cooling, but I have no idea on that, at that size they probably need A LOT of air flow. Hard to tell if those are the culprit or It sounds like you may have something else going on-

I just checked your older post and yes that half-sized looking radiator with half as many fins is not going to cool properly. Its looks 50% Less at least! IMO its more about the length of the core giving the coolant time to actually cool before being recirculated back to engine.

I would still start by checking flow rate as mentioned above. Higher pressure rad cap, or just one with a gauge so you know what is going on. I would pop of the flywheel cover and check your timing marks make sure that it is not retarded, more common then you would think. . That will make it want to run hot. Also there is the possibility your bike is actually leaning out while riding, I've seen the reeds or other spots leak when at mid to upper range and pull excess air leaning the mixture and causing the bike to get hot fast.

Just some ideas... first off I would get some OEM radiators, eBay doesn't work for you out there?

Heres a decent looking pair.... Even slightly bent or smashed on their worst day half empty should work better then the half-sized units.

$81

https://www.ebay.com/itm/KAWASAKI-KDX22 ... ondition=4

You can of course find better units on there for about $75-$100 per side. I have had smushed radiator on more then one bike and they can still work fine. If you want a better looking one I understand.

[kdxdazz]

Cheers guys, good info, as was mentioned I run the hacksaw blade through and even though I cleared the ends I might have missed dirt on the inside, could corrosion and a thin layer of dirt on the inside reduce cooling efficiency, when I tig welded them back together I spent a bit of time filling up with water, shaking them about and emptying them but nothing came out, I flushed the whole system, I've never heard of flow checking, I will Google that or if anybody can give me some pointers. Included a photo of how bad they were when first blocked, I did have a crack on the carb which I found with a leak down test but sealed that up with rtv silicone. I know I sound like an old washer woman whining about issues but this bike has been nothing but 2 years of problems, and mechanics in Thailand are inept at the best of times so I have to do what I can in an apartment with minimum tooling.

[KDXGarage]

WOW! THAT'S CLOGGED!

[PacificNWRider]

Yeah that's bad.. seen some early bikes look like that, usually from filling with hard water (NOT distilled) or some sort of electrolysis problem, like not having a good ground or a loose one, or wacky headlight wiring.

If I was you I would bite the bullet and try to buy some OEM radiatorss off eBay. Each side is $99 for a good one and that will get you good in the radiator department. Then if its still overheating, you can track it down, shouldn't be too hard.

As for now, If I was you I would fill the cooling system up with 50/50 vinegar / water , run the bike for like 10 minutes or until it gets warm and then flush the system out. Im guessing a ton of crap comes out. Let us know!

make sure you flush it really good afterwards, then fill it up, get it warm, and flush it once more

[kdxdazz]

Radiators arrived today, 120 Australian dollars delivered. The radiator cores are one large core rather than 2 small cores as in my previous photo.