Author Topic: New Radiators??? (Read 7075 times)

stokester · « **on:** October 06, 2024, 05:14:14 PM »

I returned from my ride to Morton's BMW in Fredericksburg VA to see a small puddle of coolant on the concrete.

The initial inspection looks like the radiator may have sprung a leak as I did not see any indication of leaking around any hose connection or from the cap. I think the radiator will have to be removed to be certain but I have a couple of questions for those who may have dealt with this.

- is there a way to do a pressure test on that radiator without a special adapter for my Stant kit?
- has anyone purchase/used one of the new radiators found on eBay?

Scott_ · « **Reply #1 on:** October 06, 2024, 09:43:06 PM »

How's the weep hole at the water/oil pump......
As far as pressure testing your system, you may have to find an old radiator cap and attach your fitting needed for your Stant tester.
My radiator pressure tester only seems to have caps/adapters for the standard twist caps, not a threaded cap.

stokester · « **Reply #2 on:** October 07, 2024, 05:55:06 AM »

Quote from: Scott_ on October 06, 2024, 09:43:06 PM

How's the weep hole at the water/oil pump......
As far as pressure testing your system, you may have to find an old radiator cap and attach your fitting needed for your Stant tester.
My radiator pressure tester only seems to have caps/adapters for the standard twist caps, not a threaded cap.

It's not coming from the weep hole (I've replaced the seal) and the radiator is wet. The top of the engine shows signs of coolant leaking on it so I'm pretty sure it's the radiator but won't know for sure until I remove it.

I was thinking of using an old cap to make an adapter as my Stant kit only has GM twist ones. If I remember right they are pretty damn expensive too.

If a new radiator is needed I will first post a WTB ad here to get one before going on eBay. While those new aluminum ones look nice I am concerned about the fit.

Laitch · « **Reply #3 on:** October 07, 2024, 09:28:03 AM »

Quote from: stokester on October 07, 2024, 05:55:06 AM

While those new aluminum ones look nice I am concerned about the fit.

Here's a somewhat relevant review from 2020.

stokester · « **Reply #4 on:** October 07, 2024, 11:24:16 AM »

Quote from: Laitch on October 07, 2024, 09:28:03 AM

Here's a somewhat relevant review from 2020.

Thanks Laitch. Very helpful.

As soon as I get the R100RT prepped for my November trip then the brick goes up on the lift.

stokester · « **Reply #5 on:** October 07, 2024, 03:40:23 PM »

Well... it's the radiator which apparently has a pinhole near the very center.

I solved the issue of finding the leak by attaching some tubing to the nipple that goes to the reservoir and using a basketball pump to pressurize the system. After watching the fluid drip out I drained the system, pressurized it and then sprayed it with soapy water to confirm.
Now to decide a replacement and whether to replace the fan at the same time...

Laitch · « **Reply #6 on:** October 07, 2024, 05:01:07 PM »

Quote from: stokester on October 07, 2024, 03:40:23 PM

I solved the issue of finding the leak by attaching some tubing to the nipple that goes to the reservoir and using a basketball pump to pressurize the system. After watching the fluid drip out I drained the system, pressurized it and then sprayed it with soapy water to confirm.

sooprvylyn · « **Reply #7 on:** October 07, 2024, 05:21:37 PM »

The leak may be caused by the fan. The OEM fans on K-bikes, at least the k1100s but probably all of them, tend to drill into the back of the radiatior, exactly where you see those bubbles.

Ive used one of the ebay radiators on my k1100, works just fine and looks quite nice. Had one in my k75 too, but it was advertised as k75 fan IIRC and not k100.

sooprvylyn · « **Reply #8 on:** October 07, 2024, 05:22:36 PM »

Quote from: stokester on October 07, 2024, 03:40:23 PM

Well... it's the radiator which apparently has a pinhole near the very center.

I solved the issue of finding the leak by attaching some tubing to the nipple that goes to the reservoir and using a basketball pump to pressurize the system. After watching the fluid drip out I drained the system, pressurized it and then sprayed it with soapy water to confirm.
Now to decide a replacement and whether to replace the fan at the same time...

You probably do want to replace that fan. When you take the radiator off, and remove the fan, look at where the middle of the fan was in relation to the radiator...bet its been drilled through by the fan.

stokester · « **Reply #9 on:** October 10, 2024, 05:20:15 PM »

I will remove the old radiator as soon as my replacement and Spal fan assembly arrives.

Pics will be posted.

frankenduck · « **Reply #10 on:** October 11, 2024, 11:05:19 PM »

FYI: You don't need a fancy mounting plate for the Spal fan:

https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/fans/fans.htm

It ain't pretty but nobody can see it.

sooprvylyn · « **Reply #11 on:** October 14, 2024, 12:30:29 PM »

Yep, I used steel strapping to mount mine on my k75. Worked just fine.

stokester · « **Reply #12 on:** October 15, 2024, 01:35:21 PM »

Well the verdict is in.

The fan worked its way off the shaft to contact the radiator causing it to bore a hole.
It moved about 10cm to contact the radiator and cause the damage - on a motorcycle with less than 15k miles

With the Spal fan here and the replacement radiator to arrive today, I should have it back on the road this week.

Pics include how I pressurized the system with the basketball pump to find the leak and comparison of fans where you can see the distance it moved.

Laitch · « **Reply #13 on:** October 15, 2024, 01:44:58 PM »

frankenduck · « **Reply #14 on:** October 15, 2024, 02:00:05 PM »

That happened at only 15K? Sheesh!

sooprvylyn · « **Reply #15 on:** October 15, 2024, 07:13:47 PM »

Quote from: stokester on October 15, 2024, 01:35:21 PM

Well the verdict is in.

The fan worked its way off the shaft to contact the radiator causing it to bore a hole.
It moved about 10cm to contact the radiator and cause the damage - on a motorcycle with less than 15k miles

With the Spal fan here and the replacement radiator to arrive today, I should have it back on the road this week.

Pics include how I pressurized the system with the basketball pump to find the leak and comparison of fans where you can see the distance it moved.

Laitch, was it you who said you'd send me some type of food and a pajamas of my choosing if his fan drilled into the back of his radiator? I could swear it was you, but cant seem to find the post where it was said.......

Laitch · « **Reply #16 on:** October 16, 2024, 04:44:36 PM »

sooprvylyn · « **Reply #17 on:** October 16, 2024, 07:01:00 PM »

I was really looking forward to updating my profile pic wearing the PJs

Laitch · « **Reply #18 on:** October 16, 2024, 07:20:37 PM »

Pajamas can be substituted. They ship better too. Message me the address where you want to receive your award.

stokester · « **Reply #19 on:** October 18, 2024, 07:27:05 AM »

The replacement radiator has arrived, cleaned up and reinstalled with a new Spal fan. Just waiting to change oil and run it to ensure all is well.

I did remove the original fan from the motor to find that it must only be a press fit of a plastic fan on a motor shaft. No circlip, no retainer of any sort. Apparently it works for the majority of installations but seems to be a weak point for some.

What do these number buttons indicate?

Scott_ · « **Reply #20 on:** October 18, 2024, 05:33:47 PM »

Inspector ID from factory???

News:

Author Topic: New Radiators??? (Read 7075 times)