Disable Radiator Fan

gatdammit · Apr 9, 2020

Stradista's,

My radiator is leaking at the lower mount for the left side radiator fan. When the fans kick on at speed, it blows coolant all down the left side of the bike and pant/boot. It only leaks under these conditions - no static leak. I fitted a shroud around the fan housing, which helped a little. I also tried blocking the open air flow at that section of the radiator, which didn't seam to do anything.

Was wondering if any of you wiring/ electrical geeks knows if I can disable that fan individually or if it's tied to a bespoke fuse I can pull. Thanks.

gatdammit · Apr 10, 2020

I looked at the parts fiche and it's just a single lead connector for both fans. I just hope I can get to it without pulling the tank

edgary · Apr 10, 2020

I looked at the electrical diagram and it doesn't seem to go to a fuse, although I'll admit that I'm no electrical wizard. Didn't think to look at the parts diagram, though, so kudos to you

elephantwithtrexarms · Apr 10, 2020

Sounds like you need a new radiator

gatdammit · Apr 12, 2020

Fan plugs are located on frame to left and right of steering neck. Literally turn the bars and it's mounted right next to inner black fairing on either side.

Ya, I fought a radiator leak for years using every off the shelf welding goop they sell. In the US, no one would weld it on the bike for safety concerns. When I moved to Italy, local Duc shop said "no problem". It was a dealership, too. I think I can take the fan off without removing the radiator. It's still cool out and there is no traffic right now so I'm comfortable running single fan to trouble shoot. Since there's no static leak, I might be able to patch it.

m00se · May 5, 2020

I found a needle sized hole in my radiator two years ago. Same as you it only leaked when the bike came up to temperatures ~100C.
Took it off the bike to drain it and JB weld it. It did the trick for a better part of a year, but started leaking just barely towards the end of last year. Once I saw how outrageous the price of a replacement unit is, I resorted to just living with it.
I was able to unplug the rad fans without needing to remove the gas tank. It just took long fingers. I don't know that removing the fans will be possible without removing the radiator though. Let me now if you do!

Sent from my Pixel 4 XL using Tapatalk

gatdammit · May 5, 2020

$700!!! I was checking out some affordable aftermarket "racing" radiators but, none of them have fan mounts. I can't stand the spray all over my left leg, boot and plastics. I've since surrounded it with shield ducts and sponges. Disconnecting the fan didn't help. I've finally tamed it to almost no spray, but it's still leaking at temp. I have an FPO address so ordering a used one is proving difficult.

You have to drop the radiator to remove the fans. I can handle removing the radiator but I know a JB Weld patch won't hold as the fan mount location will just weaken it in short time. My front wheel leaves the ground from time to time, so I guess it's karma.

Araitim · May 5, 2020

A radiator repair shop should fix it for under $100 or you can go grab a propane (or mapp) gas and some low temp aluminum brazing rod (available at home depot, menards, harbor freight , etc) for like $15. Once yoy heat the part the rod can flow like solder(you can also heat it less and build up features or thicker areas if yoy want but that won't be necessary here). Whole bunch of videos out there and it's very easy to do. I have made many parts and brazed them together using this including a secondary rear hand brake caliper mount for my old supermoto(for stunts). It literally held a brake caliper mount in place without issue for years. The new owner still uses it without issue.

gatdammit · May 5, 2020

I live on a Navy base in Italy, with no garage. After spending a winter doing the hydraulic swap and starter repair in the open cold/rain, I've accepted the fact that my DIY'ness is severely neutered. Although, I can certainly find a shop to repair it once I yank it off. There's actually a junior gp race shop near by. I've just lost so much riding time to repairs the past 18 months that I'm very hesitant to put her on blocks again. Commuting on 4 wheels in non-COVID traffic is just awful here.

Learning to weld is very high on my bucket list. My dad just finished his master 3 bay detached garage and we plan to build a car after I retire soon. He's a great mechanic but has rudimentary torch skills. In north Florida, there's a Billy Bob's muffler shop every 5 miles that will weld anything you got the cash for...so, always a skill left to the pros.

Araitim · May 5, 2020

An old school method for sealing tiny leaks is to put a table spoon of pepper(thats right, pepper you use to season food. As in salt and pepper)I with your coolant. Another method is to put a raw egg in with your coolant(although that is usually used for a bigger temporary job). Ask your dad about these methods. I'm sure he has heard of them. They were commonly used in the 60s and 70s. They are both completely reversable with a coolant flush unlike the additives you get at the autoparts stores because they never solidify, they float around till they find a spot to leak out then they stack up on themselves.

I believe you have the ability(if not, I'm positive your dad does) to do the low temp brazing. Its not like normal brazing where you need to control heat exactly. Just apply heat, scratch surface with rod , apply heat, scratch surface till the rod flows like solder. But if thats not something you want to get into I understand. Ask him abut the pepper trick. It should easily get you through another season till we are back to winter down time.

Disable Radiator Fan

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