I've had my 2003 XB9S for over six years and haven't had any significant problems with it.

However, a few weeks ago, the first ride of the year ended with a horrible clicking noise when I switched off and the fan started up. The load on the fan motor caused the fuse to blow. I guessed that maybe something had got into the fan assembly (e.g. dead spider) over the winter and used EcmSpy to clear the fault code and run the fan diagnostic after replacing the fuse. The fan spins without any problems and the diagnostic test passed OK. So I assumed that whatever the obstruction was, it had cleared itself.

The next time I rode the bike I noticed that the fan wasn't coming on. I switched off the ignition and switched on again and confirmed that after three seconds the engine check light came on - i.e. the fan was dead again. I checked the fuse and it was blown. EcmSpy showed the error code for a fan problem.

I bought a second hand fan off eBay. It's date stamped 2005 (so a couple of years newer than the one on my bike) and tested it on a 12v supply - it's working fine.

I removed the old fan and put the new one in this morning. I replaced the fuse and ran the EcmSpy fan diagnostic and it passed OK.

I went out for 15 minute ride to check everything is OK but when I switched off and the fan came on, there's a clicking noise again but t's not as bad as it was and the fan continues to spin and the clicking goes away when the fan speed drops to low speed.

I went out for a longer ride this afternoon and when I got back and switched off, the fan clicking was much worse.

I had assumed that the old fan was either dead or about to die but now I began to wonder if the problem is something else so I hooked it up to a 12v supply and found that it works fine. However, If I look carefully at the inside of housing, I can see that there are contact marks on the area that sits at the top, when it's installed in the bike, from the fan blades. And I can see that the fan blade tips are slightly worn from this contact too.

The clearance between the fan blade tips and the housing is definitely tighter in this area and it seems that once the fan is installed in the bike the housing is being distorted just enough to cause the fan blade tips to make contact with the housing. When the engine is hot, I'm guessing that the housing is distorted more easily because the plastic is hot and more flexible. When the engine is cold, the fan spins without any contact between the blades and the housing.

I can't understand why this is suddenly happening when it's never been a problem for the past 13 years and I've never seen this particular problem described before. I'm not sure if the fan has ever been removed from the bike previously. It had its 10,000 mile service with Maz last summer, so it may have been removed then but I can't see any obvious signs that it was.

My plan is to take the fan out again and check that there's nothing on the frame that's causing the fan housing to distort but I didn't notice anything when the fan was out this morning. After that, the only thing I can think to try is to file the tips of the fan blades so that they don't touch but this feels like I'm fixing the symptom and not the cause.

Has anyone else had a similar problem ?

(Sorry for the long post)

Steve

Mine rattles cos the bearings are fooked

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08 Specialized Langster

A couple of photos to show the problem...

The first shows the inner side of the top of the housing where the blades are making contact:



The second shows how little clearance there is between the blades and this area of the housing. Although there's no contact when the fan is removed from the bike, once it's installed the housing is compressed or distorted just enough to cause contact with the blades.



Steve

Having fiddled with a few times with no luck, would it be worth putting a spacer/shim/bit of packing between blade and housing at closest point when reassembling. Tighten all up, remove spacer and see if any better?
Or use Maz's method of lubricating XBs by immersion in deep water.

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I'm a Hornithologist, I get excited by exotic birds.........

I notice it's right opposite the loom tunnel. Have you moved or had the loom off. Is the loom sat as flush as it can be. Just a thought

I don't have a fan thingy on mine but it seems odd that the fan is only catching in one place. If it was a fooked bearing wouldn't it rattle and catch all round? It certainly looks like the casing is distorting as it's bolted up.....I take it it runs OK when off the bike?

What's the blade clearance at the diametrically opposite point of the housing? ...loosen the motor mounting screws and see if you have any 'wiggle-room' to even it up.
Also, the housing shouldn't be 'distorting' when you fasten to the bike; have a look to see why (if) it is.

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'98 M2 Razorback, it's a keeper.

I had a similar problem some years back on my XB Lightning when a plastic tab from the leading edge of my Lightning seat fell into the guard jamming the fan. I did a post called 'Tab Tip' or something.

These small (and apparently useless) tabs were merely stapled on to the inner seat edge at the factory and are a b***'d to see if they get into the fan guard. One possibility.

Thanks for all the helpful replies.

deepsix - Yes, packing it sounds like it's worth a try. In a similar vein, I wonder if I should try changing the order that I'm tightening up the bolts. Maybe try to push it down away from the top mounts to relieve any pressure at the top of the housing (where the blades are touching).

DaveH - Good thought but the loom cutout is actually on the right of both photos.

Lacy - both fans seem OK when running off the bike - no rattles or signs of bearings being tight or loose.

Rik - the blade clearance is definitely tighter where's it's touching. When the fan is off the bike, it's 1mm clearance and 2.5mm on the opposite side. I will try re-centring the motor.

edd - I don't think anything has fallen in to the fan. I can't see any signs of something being there that shouldn't.

I've done a bit more investigation and one thing that I think is now clear is that as soon as there is the slightest contact between the blades and the housing the problem gets much worse because the fan blades and the housing don't wear down but instead get hot and pliable. So instead of increased clearance on the housing because the fan blades have worn it away, I've got even less clearance because the blades have created a lip around the contact area.

My plan is:

1. Get the s/h replacement fan out of the bike and check that there's nothing on the frame that's causing the fan housing to distort.

2. Sand down the area where the blades contacted the fan housing on the original fan so that I get rid of the lip that's been created. Maybe take another 0.5mm of the inside surface away to improve the clearance.

3. Try repositioning the motor in the housing to improve the clearance.

I've seen on other Buell forums that there were a few fan replacements under warranty around 2003-2005 where the owners talked about the 'click of death'. I'm now wondering if some of these problems were not bearing failures as was commonly thought but maybe the problem I've got - not enough clearance on the fan blades. Although I still don't understand how my fan has been OK for the past 13 years and suddenly there isn't sufficient clearance.

Update...

I've noticed that the problem is worse when the engine is hot. If I run the ECMSpy fan diagnostic when the engine is cold then there doesn't seem to be a problem. But if I go out for a 30 min+ ride then, when I switch off and the fan comes on, I hear the blades clipping the housing.

Last weekend I left the bike running after a 30 minute ride, helmet off, seat off, then switched off. The fan came on and I put pressure on various parts of the housing to see what happened. Pushing the fan down in bike's frame seemed to help a little so I thought I'd try loosening off the mounting bolts as much as I could without removing the rear shock, pushing the fan down as much as I could, and tightening the bolts up again.

However, what I found was that as soon as I started loosening the two top mounting bolts, the problem went away. This is odd because all five mounting bolts were torqued up according to the figures in the manual but it seems that just backing off the spec torque slightly has fixed the problem.

I'll need to check that the bolts don't work loose but, for now, I'm happy that the fan seems to be working OK again. Sometime soon I'll take the shock out again and check the torque on the mounting bolts. I suppose, if I need a slightly lower torque setting then a drop of low strength loctite will ensure the bolts won't work loose.

sounds promising.

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I'm a Hornithologist, I get excited by exotic birds.........

Loctite 222 works for me , nice low strength for small screws , and nuts and bolts .

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Buell Ulysses XB12X 06/08

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'98 M2 Razorback, it's a keeper.