Popped a radiator this weekend....questions

05 450x....Literally stepped off the bike at about 1 mph in a really tight section on woods...turned out I put her down on a something hard. Crappy Works Connection braces bent inward and actually pierced the rad on the side...left rad....oh the irony.

Well I've got some Unibiker cages ready to mount but I need a new radiator. Plan on getting the old one repaired as well for a backup, but for now what should I be looking at the replace the broke sucker with? OEM, aftermarket? This 'crash' is going to be expensive enough so some super fancy hi-flow rads that are $$ don't make a lotta sense to me. All I'm interested in is toughness and not having to dremel my bike into swiss cheese to get a fit. Best place to grab them online too while we're at it.

To replace, I'm guessing it's simple as drain coolant, remove hoses, replace rad and top off coolant? Do you have to purge the air from the system? If so how do I go about doing this. I just plan on running a vanilla ethleyneglycol/water mix.

I plan on replacing all of the coolant rubber hoses while I'm in there screwing around....should I just buy then precut and formed or would a generic roll of hose be just as effective? What gauge is the stuff anyway?

Thanks for any info!

+1 on motorcycle radiators. They fix it and buy some unabiker guards once you get it repaired

I installed the devol raditor guards. I had ordered the works connection ones and upon reciept in my engineering head - could not see how they wouold off much if any support, so I sent them back and ordered and installed the Devols.

I talked to Mylers and check out their site. Was thinking to tossing on one of their supercool rads as a replacment....they're cheaper than oem and look sturider. Anyone used them before? Have issues fitting Unibiker braces over them? CS at Mylers couldn't answer these questions for me but they did say that they aren't the same exact size as oem.

That's a great question, butter. I was thinking of putting bigger rads on my 450R and replacing the left rad on my 450X so I would like to know what guards will fit. I'm pretty sure the Flatland guards I have on the 450X will fit over larger rads front to back but not side to side wider or top to bottom taller. Let us know what you find out.

I did the exact same thing yesterday- fell off towards the downhill side of the bike and my left rad is crunched (along with a rib or 2 and some plastic).

WC "guards" are worthless for the kind of riding most of us do on the X- about the only thing they might be good for is on a track where weight might be of more importance. The only reason I went with them is because I got them free, but it'll be the Mohards for me once I get this thing fixed or replaced.

I have heard good things about both of those places, as well, Mylers inparticular.

I m an austalian and use a aussie product made by force i use there rad guards and there 1 bolt to remove bash plate which is also great for doing oil changes. I have had a couple slow speed drops guards are great no damage to them or radiators plastics did sustain a few scratches. http://www.forceaccessories.com.au/index.php Just another option that might be worth a look if your looking for something a bit different have a look.

thanks clint for the link to force, im a aussie too and the skid plates and stuff gives major protection =-), btw fyi i dont have a crfx yet lol , but yer judging by tha pics

Too bad you didn't bust the other radiator as well because I would recommend a set of Fluidyne radiators. They're only $50 more per radiator and much better than OEM. Otherwise, I'd just pay the $200 for an OEM left-side radiator unless it's not destroyed, in which case a good repair shop should be able to fix it almost good as new. I tacoed a KTM radiator and had a place in Utah fix it... nearly perfect.

Get OEM radiator hoses or the CV4 hoses if they really need to be replaced. They're shaped and bent appropriately. Don't try to make your own.

I honestly don't know what the procedure is for changing out the radiator fluid. It's one of the topics the owners manual avoids covering. In fact it even says something like, "only a professional mechanic with the right tools" should change the radiator fluid. I'm not sure why they call this out. Seems odd. On my KTMs, you had to bleed the head, but I don't think you need to do that on the Jap bikes for some reason.

If someone knows the proper procedure for changing the radiator fluid, it would be helpful as I'd like to know if there's a special step or some specific reason why Honda would say have a professional do it, even though they go on to explain how to change the oil and adjust the valves in the owners manual - two jobs I would argue should require more expertise than changing radiator fluid.

Cut and paste from the service manual:


Remove the right and center engine guard (page 2-5).

Remove the radiator cap.

Drain the coolant from the system by removing the

drain bolt and sealing washer on the water pump


Reinstall the drain bolt with a new sealing washer.

Tighten the drain bolt securely.

Disconnect the siphon hose from the reservoir tank.

Remove the reservoir tank cap and reservoir tank.

Drain the reservoir tank coolant.

Empty the coolant and rinse the inside of the reservoir

tank with water.

Reinstall the reservoir tank and connect the radiator

siphon hose.

Fill the system with the recommended coolant

through the filler opening up to the filler neck.

Lean the machine approximately 20° to the right

and left several times to bleed any air trapped in the

cooling system. If the coolant level drops, add more

coolant and repeat the air bleeding procedure.


1.11 liter (1.16 US qt, 0.97 lmp qt) at change

Remove the radiator reservoir tank cap and fill the

reservoir tank to the upper level line.

Bleed air from the system as follow:

1. Shift the transmission into neutral. Start the

engine and let it idle for 2 – 3 minutes.

2. Snap the throttle three to four times to bleed air

from the system.

3. Stop the engine and add coolant up to proper

level if necessary. Reinstall the radiator cap.

4. Check the level of coolant in the reservoir tank

and fill to the "UPPER" level line if it is low.

mohards are alittle spendy but they have saved me 2x now from certain radiator replacment. They wrap around the bottom very nicely and are a must have for woods riding in my book.

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