"in situ" radiator repair? - Kawasaki KLR 650 Forum
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post #1 of 8 Old 08-07-2019, 12:56 PM Thread Starter
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Join Date: Feb 2017
Location: Denver, Colorado
Posts: 84
"in situ" radiator repair?


Long time, no posting, but I've got a question.

Had a small mishap on the Colorado BDR and got a small leak in my radiator - it doesn't seem to be losing much fluid, but there's that tell-tale green corrosion leaving a trail from the top to the bottom on the inboard side of the radiator.

I'm wondering if anyone has had any luck repairing a small leak with JB Weld or similar, while the radiator is still mounted on the bike. I'd really like to avoid the whole draining, removal, and repair process if possible, until it starts getting too cold to ride. Of course, I'll keep an eye on the fluid level in the meantime.

Any thoughts or advice would be greatly appreciated.

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post #2 of 8 Old 08-07-2019, 01:09 PM
Join Date: Nov 2009
Location: Lander, Wyoming
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Several members have used JB Quick to continue their travels. GoMotor comes to my mind. Gotta' tilt it just so & get it CLEAN, DRY & Scuffed to give it some 'tooth'.

Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
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post #3 of 8 Old 08-08-2019, 08:40 AM
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Nothing against in situ epoxy radiator repair; however, perhaps in expediency or in addition to the technique:

At the risk of being considered, "old-fashioned," "obsolete," "behind-the-times," I'll point out: Your friendly local auto parts store has an entire arsenal of products on his shelves, specifically designed to stop radiator leaks. One follows directions, essentially adding the recommended volume of the product into the radiator, where the compound mixes with the coolant and seals leaks.

"Bar's Leaks," I think, is one of the several brands of radiator leak-stoppers available. EDIT: Corroborated by this "hit," among others, on Google: https://www.carbibles.com/best-radiator-stop-leak/ [/edit]

Not the best practice? Perhaps not, but . . . whatever consequences from using coolant additive might occur, usually not as severe as burning up an engine, IMHO.


(Never tried it, but . . . some say horse dung works, in a pinch.)

“You better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, you’re gonna be dead.” "John Russell" (Paul Newman), Hombre

Last edited by Damocles; 08-08-2019 at 08:45 AM.
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post #4 of 8 Old 08-08-2019, 01:11 PM Thread Starter
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Location: Denver, Colorado
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Thanks so much for the responses -

I also considered trying one (or more) of the "miracle solutions" available, but was concerned that they might damage some of the other components (e.g., water pump, etc) - no matter what the package says.

I pulled the left lower fairing yesterday and although the fluid level is good, it looks like the upper inboard side got smacked with a rock - some of the fins are smooshed and I couldn't find the leaky spot without pressure.

I think the best course of action is to take it down to the local radiator shop for testing/repair at some future time, but it's not leaking much, so I'll just keep a close eye on the fluid level this weekend.

Oh well - it looks like a radiator repair will be one of my lasting souvenirs of either the Idaho or Colorado BDRs (not sure which one it was...), but it is better than a broken bone (or more).

Thanks again!
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post #5 of 8 Old 08-09-2019, 01:41 AM
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I'm sure pdwestman, who also responded, shares my sentiments, KLR Kool-Aid; you're welcome!

I regret neither of us, nor any other website member, offered suggestions useful to you.

Otherwise, thank you for sharing information of your conquest of the Idaho and Colorado BDRs! Congratulations!

“You better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, you’re gonna be dead.” "John Russell" (Paul Newman), Hombre
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post #6 of 8 Old 08-10-2019, 08:35 AM
Join Date: Mar 2018
Location: Villa Rica, Ga
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If you plan to replace the radiator this winter, a total redneck repair would be to use a pair of needle nose pliers and crimp the one tube that is leaking. This method is usually reserved for getting home when you are 50 miles from civilization.
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post #7 of 8 Old 08-12-2019, 12:29 PM Thread Starter
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Location: Denver, Colorado
Posts: 84
So, I pulled the radiator this weekend and although I know about where it's leaking and gave it a thorough examination, I could not find the damaged area. I think that this might be a good time to upgrade to one of Myler's super-radiators and just be done with it. Oh well...

Thanks again for all the advice and recommendations!
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post #8 of 8 Old 08-12-2019, 10:07 PM
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To make a short story long........I have experience with little leaks and big leaks and little stock radiators and big Mylers radiators on my gen2 KLR. They are all mostly fixable with JB Weld.

I discovered one little leak as I was entering the Black Dragon wash on the Trans-America Trail in Utah on a very hot day. I thought about going back to Green River, Utah for a radiator shop fix, but I wanted to ride the Black Dragon and had three quarts of drinking water with me, so on I went. I made it through the wash in an hour or so and rode back to Green River and asked at an auto parts store where to find a radiator shop. They said "the only one is behind the store, but it burned down last week." So, I bought some stop leak and rode on to the Pacific with just a small leak occurring near the Pacific where I had a shop fix it.

The big leak occurred when I dropped the bike in a corn field in Saskatchewan on the Trans-Canada Adventure Trail. It was big enough to stick a pencil in. I got out my small tubes of JB Weld and fixed it well enough to make it to a town to buy some big tubes of JB. With that I fixed it well enough to make it home to Houston with a stop at Pdwestman's shop in Wyoming.

Bottom line......JB Weld works fine. I didn't even have anything to clean it with.

The radiator was bent and twisted pretty badly, so I replaced it with an oversized one from Mylers. It has the same face dimensions, but is twice as thick as the stock gen2 radiator and cost less than a factory replacement. It works fine, but I never felt like the stock gen2 radiator was insufficient. Some say the gen1 radiators are smaller and marginal in the worst conditions.

Last edited by GoMotor; 08-12-2019 at 10:11 PM. Reason: After thought
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