Author Topic: So these radiator fans are crap. (Read 80690 times)

Gio · « **Reply #25 on:** February 11, 2015, 05:51:49 PM »

Pondering on the question of the fan on my K75 at the moment - I just checked with a long screwdriver and sure enough the blades do turn - but with the resistance described elsewhere (ie feels like the fan blade is just spinning on a seized shaft). This is the first time I've even checked the fan since owning the bike (although did not do that many miles over in the UK) and have never seen the over-temp (red?) light come on - even on longer rides. Perhaps the fan simply does not kick-in frequently enough to keep it healthy?

So I'm wondering if, in a generally cooler maritime climate such as mine (we do get the odd very hot day in summer - but typically 20 to 30c) there is enough cooling capacity in the radiator, without the fan? Of course in an ideal world it should be replaced and working ... but up to my elbows in other projects ie looking for an excuse to put this one off for a while ... probably not the first to have this thought!

Comments?

Gio

Inge K. · « **Reply #26 on:** February 11, 2015, 06:53:48 PM »

Quote from: Gio on February 11, 2015, 05:51:49 PM

So I'm wondering if, in a generally cooler maritime climate such as mine (we do get the odd very hot day in summer - but typically 20 to 30c) there is enough cooling capacity in the radiator, without the fan?

Under these circumstances the fan will kick in only standing still and slow moving traffic.
Turn the bike off at stand still, and avoid slow moving traffic when possible.

Gio · « **Reply #27 on:** February 11, 2015, 07:26:40 PM »

Exactly - something I'm used to with the air/oil-cooled MG! I don't commute and live in a rural area so most (if not all) of my miles have and likely will be either highway or country roads - so as you say, if the fan never kicks in under these circumstances it may not be a surprise that eventually it seizes up through lack of activity?

Having said that, it would be nice to know that is was working if required ... hmmm.

Elipten · « **Reply #28 on:** February 14, 2015, 08:22:59 AM »

Let the bike idle until warms up and fan kicks in. Give it a shot of lube every so often. It will last if given care. Just another personality quirk of the Kbike.

Gio · « **Reply #29 on:** February 14, 2015, 08:30:52 AM »

I think that would work if the fan was in working order, but from what others describe think mine has gone due to lack of activity, crud build-up etc. I know there are some jumper tests to confirm this but not got around to that yet. Yes - we all have our quirks - just need to recognise and accept them in return for the more numerous good points, right?

I'm thinking it would be nice to have a temperature gauge of some sort rather than just the red light - haven't researched that yet.

F14CRAZY · « **Reply #30 on:** February 14, 2015, 10:07:01 AM »

Yup, the fan will only kick in if sitting in traffic. My fan wasn't working for most of last summer and I ended up running the bike pretty hot a few times. I have a VDO temperature gauge and got it around 235f. If the bike stays moving it likely won't get over 180f or so

Gio · « **Reply #31 on:** February 14, 2015, 10:21:42 AM »

Interesting - (and apologies if covered elsewhere) - at what temp does the red light come on? I'll confess my ignorance in matters of liquid cooling as the K is the first such bike I've owned ... air is way easier to maintain!

Gio

Inge K. · « **Reply #32 on:** February 14, 2015, 10:30:14 AM »

Quote from: Gio on February 14, 2015, 10:21:42 AM

at what temp does the red light come on?

Fan kicks in at 103^oC, warning light comes on at 111^oC.

Gio · « **Reply #33 on:** February 14, 2015, 12:02:06 PM »

Thanks Inge. So F14 - without your fan running on those hot days, at 235f you were only just above the temp at which the red light should show (111c = 232f) ... interested to know if it did or not?

F14CRAZY · « **Reply #34 on:** February 14, 2015, 03:00:11 PM »

Red light came on a bit before then

bocutter Ed · « **Reply #35 on:** February 14, 2015, 03:45:23 PM »

Mine was seized. I hammered back the 'tabs' to get it apart, polished the shaft, reassembled.

johnny · « **Reply #36 on:** February 14, 2015, 04:48:31 PM »

i donts know nothing abouts motobricko fans and being in the red... unless if you are talking abouts the tach... butts i think i can make a positive contribution to the cause...

1st fan failure was beyond a hundert thou on the odo... the blade had come off the shaft butts was still turning broaching away my radiator finns... replaced it before it caused radiator whack... butts we were 2 up from sea lever to 10 thou feet of nearly all switchbacks... abouts 5 thou feet it went to the red... i pulled off... figger the problem and had to decide what to do...

we went until i thought the engine was gonna explode... the radiator cap never blew... butts we were pegged in the red for quite a while... replace the fan with a used oem with documented 33 thou on it... retired the moto at 150 thou on the odo without another fan failure...

so... 150 thou on the odo... 1 oem fan replacement...

2nd fan failure was near 95 thou on the odo... it was locked up... once again an hour minimum from civilization... had to navigate 30 miles of up hill switchbacks to getts outta there... was not as simple as being at 5 thou on the other moto where we just reversed direction and basically coasted down the mountain...

this was different... we were at the lost coast... no way out except over the hill... we would ride until it pegged red... pull off and let it cool down... once we made it out of there we had 400 miles of freeway... it was abouts 110 degrees out that day... i locked it down at 80mph and it hovered below the red all the way...

replace the fan with a used oem with documented 60 thou on it... this motor failed at 110 thou with no drama... one day at a light it went red... could not hear the fan... was locked up... replaced it with a used oem with 10 thous documented on it...

so... 2 oem fans and now 120 thou on the odo...

all together abouts 300k on motobricks... replaced 3 original fans with used oem fans at a cost of approx $120...

i gotts 2 used oem replacements that are like new low miles in the basement... figger should score a couple goods ones when i donts need them...

now to the matter at hand... i will idle them till that fan comes on on a regular basis... especially after riding in the rain or after a wash... im not worried abouts riding in the red... i thinks it will be ok when you can getts some air flowing...

j o

Gio · « **Reply #37 on:** February 14, 2015, 06:09:19 PM »

That's not a bad record Johnny ... 300k / 3 fans = 100k per fan - that sounds like a reasonable average to me. I've yet to pull / test what I suspect is a bad fan from my K75s - and may get lucky (as bocutter sounds like he did) and get it running again - if not I may take the same route as yourself and see if I can find a working oem with low miles - PM me if you feel that one of those low-mileage in your basement is taking up too much room.

Ah yes - to get some air flowing would be nice - we are hunkering down for another expected snow storm tonight ... but spring will soon be here ..?

Gio

Roadbandit · « **Reply #38 on:** February 14, 2015, 07:08:29 PM »

I would've gone s/hand fan IF the price had've been reasonable

but at $175 ….. :yow

I politely declined and went had a bex, beer and a lay down

technostructural · « **Reply #39 on:** May 05, 2015, 10:41:27 PM »

I have a wiring question about this.

I'm at the point where I need to solder the old connector onto the Spal fan. Can anyone speak from experience which is positive and which is negative? The wiring on my bike has a brown wire, and a yellow/purple wire. I was going to assume that the latter is positive, but I really don't want to have to do it twice.

Thanks.

krissetsfire · « **Reply #40 on:** May 05, 2015, 11:32:24 PM »

In my manual If i'm reading this correctly br is neg and vg (violet green) pos. I'd probably put my volt meter on it to verify though or test light. Then i'd put the fan on a battery too to verify the direction. When I don't test everything before I complete something I always ends up doing it again :(

noppo · « **Reply #41 on:** July 02, 2015, 06:12:20 AM »

Quote from: mjydrafter on May 13, 2013, 03:11:22 PM

*Edit to add: I got the fan here, no affiliation, just happy with them and their service. Not to mention they are locals, so I even had to pay sales tax...http://www.universalpartsinc.com/HP_Parts.asp?CAT=SPAL%20FANS%20AND%20ACCESSORIES&SUB=6.5%20INCH%20ELECTRIC%20FANS

Updated link to the fan:

http://www.universalpartsinc.com/shopping/productDetails.aspx?i=749937&c=10506

i think i'm sold on mjydrafter's mod.

noppo · « **Reply #42 on:** October 28, 2015, 10:46:40 AM »

i had the mod done 2 weeks ago, using mjdrafter's mount that he sent to me from the US. The dealer did it for me as i had other time commitments to keep . There's no way to do the job without taking the fairing totally off. The fan is almost too quiet, but really sucks in the air. The dealer setup the low setting of my heated grips switch (at my request) as a manual switch for the fan, and it's proven useful once. So far, i like it a lot. But have only ridden the bike once since i got it back, but was on it for a while. When i ride it more and if i notice anything goofy, i will report back.

The Mighty Gryphon · « **Reply #43 on:** October 28, 2015, 01:15:11 PM »

I did the RoadBandit version of the mod to my K100RS back in August. After I got the fairings off it took about two hours to modify the fan bracket, mount the fan, clean out the radiator fins, and do a flush of the radiator.

With the manual override, I can sit in traffic and not have the temperature get scary. Going to do my K75RT this winter. Fan still works, but has a lot of miles on it. Doing it more as a preemptive fix before I have a hot weather problem.

Vespa no more · « **Reply #44 on:** September 25, 2016, 03:04:18 AM »

Having been shouted down by Gryph and Laitch, replaced near-dead fan with Spal 6.5”

Followed Roadbandit's approach above. Initially planned to use the plate but wanted it to appear original.

Suggestion: Plastic weld the original fan shroud with off cuts and large soldering iron. Pics should be self explanatory.
Notes:

When cutting the plastic or both old fan and new Spal, the solid masonry disc worked perfectly.

Keep the off cuts for welding.

Final cleaning up done with drum sander (cheapie from Harbour Freight etc) on hand drill. The larger drum gives a higher surface speed and easier removal of material. Smaller drums and final hand sand as needed.

The two gaps created after cutting / expanding the fan shroud can be quite easily filled with the two smaller fan supports. I reduced mine on a belt sander and heated to create curve. Shroud is clipped around new fan to eliminate play later.

Plastic welding: using a large soldering iron, I tried to create a vee between the joints and then fill with off-cuts melted into the space. I guess the idea is to create a vee from both sides that almost touch for proper penetration (mine could have been deeper). Leave some excess and remove with drum sander. This process is very easy with thick plastic – especially one that is really out of sight and wont get seen. Strength of the joints was surprisingly good – I twisted it a few times and had no issues.

Silicone: I had to throw two old silicone tubes away and using some grey crap. A final coat of black spray hid it satisfactorily.

Will follow wiring diagram on this forum and will use second-hand original BMW switch for impact pad.

Hope this is of some use

Regards

Guy

Question: How to lubricate the front bush on the BMW fan? Back one is easy to get at. The fan blade seems stuck on the shaft daring me to break it free.

The Mighty Gryphon · « **Reply #45 on:** September 25, 2016, 09:35:20 AM »

Wow, nice job VNM!

I wish I had the patience to do such a detailed retrofit. From what I have heard about the Spal fans, this is the last you'll have to screw with the fan on that bike.

Martin · « **Reply #46 on:** September 25, 2016, 03:39:41 PM »

I virtually did the same mod on mine with the exception I used a Davies Craig fan ( fully sealed) with OEM blades. After cutting off the excess outer rings from the new housing and the mounting arms of the OEM. I found that the outer ring on the new housing lined up with the OEM housing, so I just made some tight "U" clips and riveted it on. I also added a bypass switch and it has not missed a beat in 18years.
Regards Martin.

D.Bachtel · « **Reply #47 on:** September 25, 2016, 07:02:28 PM »

Here's an easy fix for the fan motor ....

http://www.ebay.com/itm/FIT-FOR-Bosch-Mercedes-Benz-blower-motor-0130007027-0130007305-NEW-1-PS-KIT-/152209925212?hash=item23706b245c:g:by8AAOSwZVlXtRy2&vxp=mtr

Don in Nipomo

The Mighty Gryphon · « **Reply #48 on:** September 25, 2016, 10:53:22 PM »

The problem is that the Bosch motor is crap with melting brush holders and replacing with another Bosch motor is a bunch of work to guarantee the same problems down the road. The Spal is a superior fan and can be had for only 15 bucks more than the Bosch motor alone.

The Spal is so easy to retrofit that it doesn't make sense to go with the OEM or Bosch fans.

D.Bachtel · « **Reply #49 on:** September 25, 2016, 11:45:48 PM »

It's a replica of the Bosch produced in some Asian country. They did make some subtle changes and improvements.
I carefully examined both when they were on the bench.
The fit is simple enough even I could do it. It's a legitimate option.

We'll see if it lasts, mine was $40 including shipping. Came out of Latvia when I purchased it last April.

Don in Nipomo

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Author Topic: So these radiator fans are crap. (Read 80690 times)