ADVrider

Go Back   ADVrider > Bikes > Trials
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-16-2015, 07:45 AM   #1
motobene OP
Motoing for 44 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,169
Quick Fix Fan Dry Bearing Squeal

I have used a quick fix for radiator fan bearing squeal I want to pass on.

Yesterday during a test ride of the 300 after some maintenance work in prep for this weekend's President's Cup in North Texas, the 300's fan lit up on and off frequently, then it squealed. Once a squal starts it tens to keep doing so because the journal bearing in the fan has reached a state of being bone dry.

A dry bearing can wear itself out eventually in runaway fashion when squealing, which is the shaft chattering at high frequency, so I immediately 'fix it.' The fix is very easy taking all of... 10 seconds.

One of my cherished tools is all-brass pump oil can Eagle No. 66 with a brass straight stem and a machined tapered tip. If you can find one of these it's a gem. Snap it up! It's the tool to oil pivots, cables, whatever.

I never have dry pivots if I can help it, so my controls are always very smooth. Dry stuff wears out fast. 'Wet' stuff seems to not wear at all. Spray oil tends to be lighter and doesn't last as long. WD-40 is mostly solvent with a little oil. Good to use when you have nothing, but it doesn't last long. Synthetic ATF is my preferred lube.

So to fix my fan I simply insert the tip and contact the TOP junction of the rotating part of the fan and the fixed housing directly in front of it. I give it a couple of pumps. Oil will run down inside then wet the journal bearing of the fan. Once wet, the oil will last many months.

Yup, some oil will fling out, but the job is done and the excess can be washed off.
motobene is offline   Reply With Quote
Old 01-16-2015, 08:02 AM   #2
mung
Studly Adventurer
 
Joined: Apr 2008
Location: Idaho
Oddometer: 582
Would it be worth doing this before the squeak starts ? Maybe once a year from new to extend the motors life ?
mung is offline   Reply With Quote
Old 01-16-2015, 12:57 PM   #3
Sting32
Trials Evangelist
 
Joined: Oct 2009
Location: Minneapolis, Ks
Oddometer: 1,310
Quote:
Originally Posted by mung View Post
Would it be worth doing this before the squeak starts ? Maybe once a year from new to extend the motors life ?
Bene, experiment with silicone based oils, and maybe teflon or graphite ones as well, and others will you? I wanna know which lube is really the best, because as you know once they start the squealing, they seem to get dry and squeal more often? I was thinking of attempting to force some "seal lube" grease, see if it will last longer, but the bikes I have right now haven't squealed yet.

Just a thought :P
Sting32 is offline   Reply With Quote
Old 01-16-2015, 10:16 PM   #4
Little R
Adventurer
 
Joined: Feb 2012
Location: SLV Colorado
Oddometer: 62
Has anyone tried to take the fan off the motor shaft to gain access to the bearing? I had the fan motor off and i couldn't tell if it is pressed on or threaded. Its still working, so I didn't want to find out.
Little R is offline   Reply With Quote
Old 01-18-2015, 07:27 PM   #5
Undertheoaks
Adventurer
 
Undertheoaks's Avatar
 
Joined: Aug 2007
Location: Bay Area, Ca
Oddometer: 54
Thanks I have a 05 GasGAs 280pro TXT and it(fan) started squealing I wasn't sure what was causing it. I'll give it a try.
Undertheoaks is offline   Reply With Quote
Old 01-19-2015, 12:17 AM   #6
motodojo
n00b
 
Joined: Dec 2014
Oddometer: 6
My fan started squealing and I lubed it for about a year then it burned out. You can replace the motor for less then $10.
http://amzn.com/B00OK8POV8
http://www.trossenrobotics.com/store...Motor-12V.aspx
http://www.trialscentral.com/forums/...r-replacement/
motodojo is offline   Reply With Quote
Old 01-19-2015, 07:17 AM   #7
motobene OP
Motoing for 44 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,169
Quote:
Originally Posted by mung View Post
Would it be worth doing this before the squeak starts ? Maybe once a year from new to extend the motors life ?
I recon so. The hard part is without squealing you don't know if you've hit the target. then again, it would not hurt.
motobene is offline   Reply With Quote
Old 01-19-2015, 07:28 AM   #8
motobene OP
Motoing for 44 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,169
Quote:
Originally Posted by Sting32 View Post
Bene, experiment with silicone based oils, and maybe teflon or graphite ones as well, and others will you? I wanna know which lube is really the best, because as you know once they start the squealing, they seem to get dry and squeal more often? I was thinking of attempting to force some "seal lube" grease, see if it will last longer, but the bikes I have right now haven't squealed yet.

Just a thought :P
Yes. A squeal is when the shaft and journal bearing clearances opens up (we're talking by like some small percentage of the diameter of a hair), AND the original lube dries migrates out and the interface goes dry. Squealing, on a microscopic scale, is quite violent. The shaft is clattering around in the journal bearing bore and that will lead to rapid wear. That's why you need to catch the condition right away. If you don't, oil will shut it up, but the time until the next squeal will be reduced with the rapid wear due to squealing.

Those types of journal bearings do better on oils of medium viscosity. The very light oils or those super thing lubes in spray cans I don't think will last as long as a motor or automatic transmission oil. Perhaps mixing some witches brew might be an advantage? Like grease in oil, but how to get it in there?

Last time I tried to take the fan off to get directly at the journal bearing I felt I'd tear the assembly up so I just lubed it as discussed above.

Yesterday at the NTTA President's Cup in Texas, a rider from Mexico had a Sherco with a squealing fan. I tried some chain lube in there as that was all I had, but it didn't work. I don't think I hit the mark. The quirt cans that can cause a wave of oil to run down and touch the shaft seem to the best way to lube without disassembly.

Another way might be to take out the fan assembly and drill a hole though the cup-shaped cover such that you know you have a for sure direct shot at the shaft when you lube.

I rode the whole 2-day event and a few hours practice on my bike after it squealed no more than 1 minute, then I lube according to the above. I expect this to last me quite a while.
motobene is offline   Reply With Quote
Old 01-19-2015, 07:29 AM   #9
motobene OP
Motoing for 44 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,169
Quote:
Originally Posted by motodojo View Post
My fan started squealing and I lubed it for about a year then it burned out. You can replace the motor for less then $10.
http://amzn.com/B00OK8POV8
http://www.trossenrobotics.com/store...Motor-12V.aspx
http://www.trialscentral.com/forums/...r-replacement/
This is great info! When you replaced the motor, what was the nature of the interface of the fan with the shaft? Press on?
motobene is offline   Reply With Quote
Old 01-19-2015, 08:33 AM   #10
10K
Trail Runner
 
10K's Avatar
 
Joined: Sep 2004
Location: Arizona
Oddometer: 805
Check out his third link, explanation and photos.
10K is offline   Reply With Quote
Old 01-20-2015, 07:37 AM   #11
motobene OP
Motoing for 44 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,169
Quote:
Originally Posted by 10K View Post
Check out his third link, explanation and photos.
Oh yeah that helps jog the memory! Just a simple, cheap electric motor in an enclosure. The photos on the link show the motors to have 2 journal bearings (aka bushings), front and rear (some small electric motors have only one, such as some computer fan motors).

I can't say for sure in this case, but journal bearings for electric motors are sometimes made of sintered bronze. In such a small size it is possible they are screw machined from solid stock, but often they are net shape sintered with no machining process. As a result, they have generous clearance, making it essential they not be run dry or they WILL squeal.

Sintered bronze is a great bearing because, being made from a powder that is pressed together in a mold in a larger size, then fired in an oven to shrink and barely melt the particles together, they are porous. Any oil that touches them will thus be drawn in by capillary action and buffered. This is why once one is oiled it tends to not squeal for quite a while unless it's become really clapped out or the shaft has worn too.

I'm very interested in maintenance that allows parts to last the life of machines. This comes from having too many machines that I don't need to be nickel and diming me out of money. Lifetime parts often simply means not allowing interfaces to go dry and creaky or be under greased such that water can sit in dark places and start a cascade of oxidization. Fully packing roller bearings and suspension bit with heavy grease, and keeping lever pivots and kickstart swinging pivots always wet with oil, for example.

So... given this reminder info, in the next fit of maintenance I'm going to pull out the fan and put that drop of oil precisely on both ends of the motor.

motobene screwed with this post 01-20-2015 at 07:42 AM
motobene is offline   Reply With Quote
Old 01-21-2015, 09:00 AM   #12
motodojo
n00b
 
Joined: Dec 2014
Oddometer: 6
Quote:
Originally Posted by motobene View Post
This is great info! When you replaced the motor, what was the nature of the interface of the fan with the shaft? Press on?
The fan is press on. If you drill a couple of holes in the fan, you can unscrew the motor mount screws and tap the motor out with a nail and not destroy the motor.
motodojo is offline   Reply With Quote
Old 01-23-2015, 12:39 AM   #13
z@ch
Turn it up to eleven
 
z@ch's Avatar
 
Joined: Apr 2008
Location: Tejas Norte
Oddometer: 4,729
Thanks for the post 'bene.

I was also at Sundays event at Red River and I'll use your tips on the Gas Gas.
z@ch is offline   Reply With Quote
Old 01-24-2015, 07:59 AM   #14
motobene OP
Motoing for 44 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,169
Quote:
Originally Posted by z@ch View Post
Thanks for the post 'bene.

I was also at Sundays event at Red River and I'll use your tips on the Gas Gas.
Well cool. It was sure fun. I liked all the dirt banks in the sections. I hope I was entertaining when riding the master exhibition sections. The old guy riding in shorts somehow survived the experience!
motobene is offline   Reply With Quote
Old 01-24-2015, 08:21 AM   #15
z@ch
Turn it up to eleven
 
z@ch's Avatar
 
Joined: Apr 2008
Location: Tejas Norte
Oddometer: 4,729
Quote:
Originally Posted by motobene View Post
Well cool. It was sure fun. I liked all the dirt banks in the sections. I hope I was entertaining when riding the master exhibition sections. The old guy riding in shorts somehow survived the experience!
Oh, that's who you are! I'm the guy that gave you your fork protector back after exhibition 3.
z@ch is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 01:52 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014