I bought a new 25 CRF450R back in April, absolutely love the bike and it has been great otherwise. But at about 9-10 hours I noticed dirt accumulation around the water pump weep hole indicating it drip even though it was hard to catch/wasn’t dripping like crazy but still. I went the easy route knowing these seals can be finicky, and purchase the entire side case cover that includes a new water pump already, with the case gaskets etc needed. A couple engine hours later, noticed a couple drips again wth. I actually was able to get a warranty replacement through Rocky Mountain for a new side cover, just had to pay for gaskets. Repeatedly kept an eye on it every ride and no issues until I recently noticed like one drip slowly forming on start up and then it stops even with higher revs once warmed up really good. The bike sat for a couple weeks in Michigan colder weather, not sure if it can be normal for the seal to shrink and get one drip then stop once warm? For the record, all stock/stock rad cap, Honda Gn4 oil n filter changed every 3-4 hours, air filter every ride with maxima fft. I take care of my bike and it has never seen rev limiter yet. I am at 18.5 hours now. This is my 6th crf450 and am dumbfounded unless I never noticed a drip or two on my past bikes. Any help appreciated, I saw one guy on here randomly mentioned that seal failing on newest gen but that’s all I could find.
Forgot to mention bike never idles for long periods either, even then it should flow out of the over flow I would think.
Dang.
I would recommend checking the water pump shaft where the seal goes around it. For any burr scratches unsmooth surface. Possible play from the shaft.
Dirt inside the coolant maybe. I'm guessing you probably done swapped the coolant by now. Or are you reusing it after draining?
Thanks for reply, so yes coolant has been changed and I am very careful that there is no dirt inside coolant I inspect everything including the new case cover before installing for the smallest specks of anything and wipe it out. Also the shaft you are talking about is part of the new water pump assembly that comes with the side cover right? Because it is a brand new water pump for the third time essentially.
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Try a different radiator cap maybe it's bad.
I could try that, but if it was a bad radiator cap and there was pressure build up wouldn’t it run out of the over flow hose from the radiator? again as of now I get like one slow forming drop then it goes away once warmed up far as I can tell, not losing any amount of coolant.
Caps can be bad in the sense that they allow the system to over-pressurize.
Also, whatever the impeller shaft mounts in…maybe it’s bad and/or has an issue…causing the shaft to wobble/wear out the seal?
Right I understand but in that case wouldn’t it run out of the coolant overflow hose from the radiator instead? And again the weep hole forms a slow drip then stops once warmed up even while revving it up thus increasing pressure further. So I’m trying to find if a slight drip here and there is normal at all, and maybe I just never noticed on my past crf450s?
And okay that’s a good point as far as shaft wobble where water pump connects, just can’t believe that would happen on a new low hour Honda but I guess anything is possible idk
Can you store the bike, SAFELY, indoors and see if maybe it’s just cold-contraction?
Also, a cap that over-pressurizes the system won’t let the coolant get to the over-flow system.
That’s a good idea, but will have to see if the wife wants it in the living room 🤣 not sure if that will fly. Thanks for the replies and ideas, any other ones come to mind throw it at me. I’ve only had one water pump seal fail and it dripped constantly but was on a couple hundred hour 05’ CRF450 back in like 2013 that needed shaft/bearings as well.
Are you using genuine Honda antifreeze?
So the original two times it leaked I was, now it is universal 50/50. However I have used universal in all my bikes and never had an issue
Lol.
Those mechanical seals are such a pain to replace. Why does Honda use that design? Every other bike uses a simple rubber seal.
Yea I agree, that’s why I decided to go the more expensive/but less headache route of replacing the whole side cover that includes a whole new water pump with seals and still have this result. As TeamGreen stated maybe I should replace the shaft behind water pump if it is somehow off balance/machined odd from the factory? Idk. Again not sure if I’m over thinking an occasional single drop forming before warm up or not. Just bugging the s*** out of me if it’s not normal
Reminded me of that Cheech and Chong skit when Cheech’s car wouldn’t start…”have you checked the air in the tires lately?”😂😂😂
For the OP, I’d consider looking at the bearing/etc for the inside end of the pump shaft (nearest the crank). Wondering if it somehow got installed crooked and is side-loading the shaft/seal.
Edit: I’m assuming there is such a thing…I’ve never been inside a newer CRF after 08.
I would start with a new cap. Sounds like too much pressure, and obviously something has to be wrong. You’ve replaced more water pump seals in 20 hours than I have in my lifetime unfortunately lol.
I run engine ice and a twin air 1.8 rad cap in my 25 crf450r.
Damn, that's expensive. I'm.on Kawi's now but, It makes me feel like a hero to know I'm one of the few people who has properly installed a few of those seals lol. Really surprised none of the bike build/mechanic content YouTube channels have done a proper how to video on installing one.
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I had that bearing go out on an '08 450 and it caused the water pump shaft to run eccentric wearing Out The Seal took a little bit to figure it out LOL I've not been in the new 450s so I don't know if that bearing is there either
Both of our 2025 250's accumulate dirt at the weep hole. they both are at about 20 hours now and i havent needed to add any coolant at all so i know its not much. I am not going to fix anything yet, ill keep monitoring the issue. One bike has a Mylers 1.8 and the other stock cap.
Same issue here as well, basically since new it has had residue around weep hole. However, there has been no noticable anti freeze levels dropping. Currently bike has around 75 hours or so on it and got it in march and havent touched it. I also run the higher pressure cap on it as well. I agree the mechanical seal is PIA to install and not a fan of them.
Thank you appreciate the reply even though I don’t love the fact it’s happening maybe it’s just the nature of the beast and many people aren’t noticing since it’s very minor/occasionally drip on start up etc. If you ever have any other update please let me know!
Thanks for the reply, makes me feel a little more at ease that yourself and EAmato88 are seeing the same thing. Maybe I just didn’t notice on my 22 which is overall very close to same engine. Again if you ever have any other update post it or message me if you want, greatly appreciated!
just like some motor oil or some premix is better, same goes with antifreeze. Do you guys think Walmart brand antifreeze is as good as genuine Honda?
I think this is still true of Honda, they use a ceramic component on shaft seal. They are extremely difficult to replace the seal without cracking, and the reason people in the know replace the whole cover as an assembly.
I would clean weep hole area, idle bike until it's coming out overflow and hold a piece of paper by weep hole to see if it's leaking under pressure. It may only be leaking after bike is off (impeller may be sealing fine under rotation)
No problems man! My '22 was almost exactly the same as well. I would think also if it was a issue I would have overheating issues riding deep sand at Coops etc.
My 17 always had a black smudge near the weep hole even after replacing the water pump and oil seal. Still ran the bike 250 hours with no issues.... Hondas are bullet proof
If all you are getting is one drop on startup, I think you are overthinking this. It's not uncommon for bikes to have a tiny bit of wetness around this weep hole. Run it , and keep an eye on it. Rarely does this assembly have a major failure - it just starts seeping more and more.
I also ran a stock OEM 2019 KTM radiator cap. Bumps you up to a 1.8.
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