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Discussion Starter · #1 ·
As the final step in making sure all my fluids were fresh (just bought the bike a few weeks ago), I drained & refilled the radiator last night. Got everything put back together (boy, that cap really *is* a PITA, isn't it?) and rode the bike around town for a couple miles to get it up to temperature and make sure all was well.



Got it back into the garage, and could smell hot coolant. Noticed a couple drops coming down on the top of the motor towards the rear, but since it was hot, couldn't poke around to see where they were coming from. I'll have to check the overflow tube to make sure I didn't pinch and/or crack it under the fuel tank when I put it back on (took it all the way off since I wanted to clean the filter and get any varnish out)... but do you guys have any other ideas where these dribbles may have come from?



Pretty sure I got the radiator cap back on square and appropriately tightened. I'll be checking it out in more detail tonight while there's good daylight streaming into the garage.



Thanks in advance for any ideas.

-Mel
 

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The cap is a real PITA. I'd guess the drips to be residual from the overflow tube you just put back on. If you had removed the radiator for service I'd check the clamp on the upper hose.
 

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Certainly check the overflow tube but have a look at the weep hole for the waterpump.



This pic is sideways but what you are looking for it the little hole that the red tube has been stuck into.

This is on the left side of the motor just in front of the chrome tube that goes to the radiator.

If this is the culprit then you'll be looking at replacing the seal on the waterpump. Whatever you decide, don't go plugging the hole.



Plenty of info here on your options if that turns out to be the case.



Just don't shoot the messenger.
 

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Welcome to the forum and thanks for setting up your profile completely.



You are probably leaking from the "weep hole". That is a very small hole on the bottom left side of the waterpump housing that allows any excess coolant that gets by the seal to escape to the atmosphere. At this point, I wouldn't do anything but monitor the leak and make sure it isn't increasing. These seals sometimes repair themselves after a 100 miles or so of riding.



Don't try to seal up the hole with silicone, etc. It needs to be active if the mechanical seal is leaking, or the coolant will get into the crankcase oil. If after a couple hundred miles, the leak is still there, the seal can be replaced without dropping the engine. A process we call "Shep's Method". Details can be found in the Quick Reference section.
 

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If it was at the over flow tube at the top of the radiator I doubt you'd see the leak from the top of the motor at the rear ???



Is this drip possibly coming from the water pump area at the rear ?



EDIT: Well dang I see three of us answered the same way at once.....hint hint !!



EDIT AGAIN: Dang, it's good to see you back Roger.....I was gonna email you to see if you were doing OK !!
 

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Discussion Starter · #7 ·
Well, pulled the cap back off (easier now that I have the angle figured out), ran the bike up to temperature - got a couple bubbles out. No more drips, but haven't had the bike back out of the garage yet - a little rainy this evening. I will keep an eye on the system.



Thanks for the tips.
 

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I know that on some models the Rad cap clearance is tighter than on my Stock UK CX500s.On all models though it's much easier to get the Rad caps off if you release them anti-clockwise,then turn back half a turn when the cap has lifted.



HTH
 

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I had exactly the same problem, after a system refilled for the first few days it dripped from the back of the engine. Were the coolant pipe fit's into the rear of the engine.



I let it cool down and then opened the cap, it hissed a bit I topped it up slighlty. And now it's fine, no more leaks. I guess I didn't get all the air out.



Cheers



Curt
 

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Discussion Starter · #11 ·
Have ridden to work the last two days - no more dribbles. Looks like it must have just been air bubbles (as mentioned) and the bleeding advice worked out. Rain in the forecast all weekend again, then on the road for work for another 8 days. Maybe by the time I get back into town it will be warmer than 36°F in the mornings?



Thanks again for your help, guys.

-Mel
 

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I tried this on my bike. Have the same problem. Loosened the cap and let it run. Wound up with coolant all over the ground! Could not tell if there were air bubbles or not. The cap is in a bit of a tight spot
on the custom! Put the cap back on and still have a small drip. Should I repeat? Did I say that the cap is the worst design I have ever seen??!!
 

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That is not a good sign




You should be able to run with the radiator cap off until the coolant flows over the cores of the radiator inside without it bubbling over.



Are you experiencing any other symptoms like coolant in the oil/low compression/Sludge in any areas?
 

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Welcome to the forum and thanks for setting up your profile completely.



You are probably leaking from the "weep hole". That is a very small hole on the bottom left side of the waterpump housing that allows any excess coolant that gets by the seal to escape to the atmosphere. At this point, I wouldn't do anything but monitor the leak and make sure it isn't increasing. These seals sometimes repair themselves after a 100 miles or so of riding.



Don't try to seal up the hole with silicone, etc. It needs to be active if the mechanical seal is leaking, or the coolant will get into the crankcase oil. If after a couple hundred miles, the leak is still there, the seal can be replaced without dropping the engine. A process we call "Shep's Method". Details can be found in the Quick Reference section.


Timely post, I've just discovered a leak around the pump weep hole area, wot weren't there Monday. I've looked in quick reference but can't find the "sheps method" post. Can anyone give a hand.



Strange how the "doodlebug" lets me finish one job and then finds me another one to do right after.
 

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Apart from Seal (£31+ !!!!) and gasket, water pump. Anything else I need to order in for the job?,
 
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