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07-09-2008, 12:10 PM iradiate Joined on 06-16-2008 Posts 56 Radiator fan self destruct, myth or fact? There was a wikipedia write up on the CX500 that mentioned the plastic radiator fan may possibly disintergrate during extended running. How common is this really? If it is common, would replacing it with the GL500 fan be possible? ( If I understood the write up GL500 had no such issues, maybe it is a metal fan? ) Just curious as I am looking to do a few extended trips soon...   Vince    Report

07-09-2008, 12:18 PM DAVID Joined on 05-16-2007 FORNEY TX Posts 622 Re: Radiator fan self destruct, myth or fact? Same fan, same problem. They come apart around 30,000 miles give or take. Mine took out the radiator on the highway about 3 miles from my house. It didn't get hot, but dumped coolant all over my rear tire causing me to dump the bike at the first stop sign after exiting the freeway. Man that anti-freeze is slick! 82 GL500 81 KDX175 If all else fails, read the instructions    Report

07-09-2008, 12:44 PM LRCXed Joined on 05-15-2008 Sacramento, California Posts 365 Re: Radiator fan self destruct, myth or fact? The aluminum hub molded into the center of the fan collects the heat from the motor and eventually breaks down the plastic its molded into causing it to dry out and start cracking, along with age. If you have a reason to pull the radiator in the future, I would order a new one from Honda. Mine was only $40.00 or so. Good insurance. If your going to do something, do it right, don't do it half as@*d. http://globalcxglvtwins.hostingdelivered.com/    Report

07-09-2008, 3:46 PM RichNCT Joined on 03-02-2006 Posts 2,139 Re: Radiator fan self destruct, myth or fact? My brother's '82 CX500C stopped at 60k miles for a dead stator, but the fan was still going strong. They seem to start making some noise well before they go in many instances I've read of, but probably not always. Most concerns about fan destruction seem to be after they are found to be rattling or loose upon inspection, not just "out of the blue", and they advice then is replace it now I woudn't worry so much about it unless it's telling you to. Born to be relatively wild    Report

07-09-2008, 8:05 PM DAVID Joined on 05-16-2007 FORNEY TX Posts 622 Re: Radiator fan self destruct, myth or fact? Yep, mine was rattling but I didn't know it was that critical. I do now. 82 GL500 81 KDX175 If all else fails, read the instructions    Report

07-09-2008, 8:12 PM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 977 Re: Radiator fan self destruct, myth or fact? One theory is that when the bolt that holds the fan onto the camshaft is overtightened it forces the aluminum hub further onto the tapered shaft and expands it, breaking the bond between the hub and the plastic. The possibility that this could be what causes fan failures is good reason to always use a torque wrench when installing the fan. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

07-09-2008, 8:19 PM DAVID Joined on 05-16-2007 FORNEY TX Posts 622 Re: Radiator fan self destruct, myth or fact? I have seen that many times on here but I don't buy it. The plastic just gets old. 82 GL500 81 KDX175 If all else fails, read the instructions    Report

07-10-2008, 11:29 AM Navy CWO Joined on 11-09-2007 Golden, Texas Posts 26 Re: Radiator fan self destruct, myth or fact? Bought my GL500 last October.  Radiator leaked, so when I pulled it I checked the fan, due to comments I read earlier on this forum.  Found cracks radiating out from the center hub.  Bought new one from Honda for $33.00 and replaced it.  Sleep sounder now!    Report

07-10-2008, 12:16 PM enriquez Joined on 03-12-2007 San Diego, CA Posts 65 Re: Radiator fan self destruct, myth or fact? The fan on my 82 custom shattered on a trip about 100 miles from home without warning.  It busted the radiator beyond repair.  I made it home with no overheating problems while on the highway, once I got close to home the bike was seriously heating up in the stop and go.  Eventually made it home without and further damage then replaced the radiator and fan. 1979 CX500 Custom    Report

07-12-2008, 7:32 PM the cheese Joined on 11-23-2007 Baldwin,GA Posts 189 Re: Radiator fan self destruct, myth or fact? It is possible to overtighten the fan bolt and ruin a new fan. Please don't ask how I know. After I read about fans coming apart, I checked mine. Sure enough it was cracked all away round the hub. Changed it. The first thing I noticed was how quiet the bike was. Amazing how much noise the fans make. ALWAYS use a torque wrench on the fan bolt. ALWAYS use a torque wrench on the fan bolt. I guess its true, the lessons we never forget, are the ones we learn the hard way. Michael 1981 CX500 Custom Just say no to skin graphs, wear your gear!    Report

07-12-2008, 8:51 PM Blindstitch2002 Joined on 05-16-2007 Greenfield Wisconsin Posts 1,586 Re: Radiator fan self destruct, myth or fact? Any suggestions on where to buy a fan from before mine turns into schrapnel. Some days it sounds like I have a playing card in there between rpms. 1979 Honda Cx500 Custom    Report

07-12-2008, 9:13 PM Anonymous Re: Radiator fan self destruct, myth or fact? Having read about the fan problem on this board my immediate thought was, why not install an electric fan like on the modern sportbikes? Has anyone already done this and I'm behind on my reading? Cheers, 50gary

07-12-2008, 10:11 PM Blindstitch2002 Joined on 05-16-2007 Greenfield Wisconsin Posts 1,586 Re: Radiator fan self destruct, myth or fact? I seam to have read somewhere on here about electric switch operated fans. I think charles bike was electric. from charles  So I welded some tabs onto a stock CX500 fan shroud, and bolted the CBR600RR fan assembly to them. I wired the fan to a small toggle switch, which I mounted to a piece of aluminum and bolted to one of the bolts that holds the upper coolant pipe onto the heads. http://choppercharles.com/cs/chopper/default.aspx?postId=12&revSort=true 1979 Honda Cx500 Custom    Report

07-12-2008, 11:00 PM hakko808 Joined on 05-25-2008 Fargo, ND Posts 209 Re: Radiator fan self destruct, myth or fact? The 650s have thermostatically controlled electric fans, but would require some mechanical and electrical mods to swap.    Report

07-13-2008, 5:51 AM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 977 Re: Radiator fan self destruct, myth or fact? the electrical part is easy. If you have the complete rad & fan assembly it has both the fan & the temp switch so it connects to the main harness with a 2 conductor plug: ground and power-with-key-on. Mounting the 650 rad to the 500 engine hangers would be another matter. The lugs are significantly diferent and would need to be almost completely re-worked. It would probably be easy for a welder who is really good with sheet metal. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

07-13-2008, 9:58 AM kung-fu-moose Joined on 12-22-2007 Fort Qu'Appelle Saskatchewan Canada Posts 8 Re: Radiator fan self destruct, myth or fact?  I had my fan come totlally off the hub and into the rad, there was damage but it was repairable. Bieng of the mindset if it happens once it'll happen again I figured a completely different type of fan would be a better fix.  I found an electric pusher fan from an old mazda at my local wreckers and made a new rad shroud/fan mount out of an old men at work sign i had laying around. I realize that sounds like a bodge job but with a little planning, a lot of paitence, some elbow grease,sandpaper and mothers aluminum polish it turned out looking, according to my friends at least, like a factory piece. the new shroud mounts to the four bolts on the wishbone engine hanger at the front of the motor, has four ninty degree bends and a bunch of one inch holes cut with a hole saw and the fan is mounted in front of the rad instead of behind. Wiring the fan is fairly easy and I found an adjustable thermostat controll at my local speed shop, it has a sensor that mounts right in the radiator core(between the fins), simplest thing i've seen.  After getting it all put together me and my CX went on a thousand kilometer road trip and the fan worked perfect. On the highway i dont think the fan even came on, in towns and cities waiting at stop lights etc. the thermostat would work just as it's supposed to,turn the fan on at the chosen temp and shut the fan off when it cooled things down a bit. By the later part of the trip (when all my worrying, staring at the temp guage, etc. was done) the only thing that ever gave away the fact the fan was even doin it's thing was that my legs would get warmer when it came on.  Again, realizing that the factory fan was less than perfect, probably due to materials more than design, finding a more reliable type of repair was a better choice for me. Cause even if the replacement fan lasts 10,000 miles that seems like 10,000 miles to soon for me. if it doesn't kill ya it generally makes you stronger.    Report

07-13-2008, 10:37 AM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 977 Re: Radiator fan self destruct, myth or fact? Actually, as well as it was put together as decently as your description sounds, itis probably a good way to do it. My biggest concern would be clearance between the fan & the fender - there isn'tmuch room in the first place when the suspension is fully compressed. I would expect a replacement fan to last a long time provided a torque wrench is used every time. The one I bought for my GL500 lasted me something like30,000 Km and as far as i know Drew (vitter) is still using it with that engine in his bike. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

07-13-2008, 12:14 PM kung-fu-moose Joined on 12-22-2007 Fort Qu'Appelle Saskatchewan Canada Posts 8 Re: Radiator fan self destruct, myth or fact?  Clearence isn't really an issue, the fan I used is a little "pancake?" model, the motor and fan itself are only about two and a half to three inches and about half an inch to the rad the whole setup doesn't take up any more room than the stock shroud/grill that came on the bike. It had the big nasty lookin plastic job. if it doesn't kill ya it generally makes you stronger.    Report

07-13-2008, 4:13 PM Anonymous Re: Radiator fan self destruct, myth or fact? ...and the electric fan has got to save engine power/fuel, especially when it's off! Cheers, 50gary

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