Hi,

I had an accident and broken the front fender on my K75.  This is what it looks like:





So, is this worth repairing with fibreglass and Bondo? Or just buy another on the used market?

Repair it if you need to exercise your artisan side or are saving money for your first Space X ride.

There ain't no saving money for that SpaceX ride when shipping cross-border.  Those pesky Canada Post agents agents are always frisking your pockets for spare change.

Maybe I'll explore my artistic side with epoxy and plastic filler.

I think that your mudguard is terminally deceased.  I am pretty sure it is ABS or polyurethane and it will be pretty hard to get epoxy and Bondo to reliably stick to it.  Any repair you are able to make will ultimately break your heart.

How did the rest of bike the fare?

What color is that? Mystic White?

I agree with .75 that it's toast and would be easier to replace than repair.

cut it off square may look ok 

You'll spend much more money just to spray it to the same color than buying a used one...

Fiberglass won't be useful on this ABS fender.

Glad I asked.  I'll find a replacement and colour match it.

This was a garage accident.  I was on a ladder putting stuff on an upper storage shelf in the garage when the feet of the ladder slipped out from under me and I fell.  The ladder just glanced off the tire and damaged the fender.  rest of the bike is ok. I suffered a skinned and battered knee for a couple weeks.

The colour is custom.  It's not Mystic White, Its Elefantbein, a cream shade used by BMW in the fifties.

That wasn't your Larry Romestant clone was it?  Good thing the mudguard is the only damage.

You should post some photos for the inmates who are new here.  Show what a real custom Brick looks like.

It's neither ABS nor glassfibre. If you look underneath the mudguard there's a molded BMW part number that says 'Fibron'.

https://forums.bmwmoa.org/showthread.php?38950-What-type-of-plastic-is-the-K75S-bodywork-made-of&p=493002&viewfull=1#post493002

Link through from this thread:

https://www.k100-forum.com/t16897-plastics-use-on-kbikes

@point-seven-five:  Yes, it was the Larry Romestand clone that got damaged.  Unfortunate but it could have been worse if the ladder was closer to the bike or if the handlebars not turned.

@dai:  thanks for those links.   Reading the posts to both lead me to think .75 is correct; it's probably ABS plastic and not Fibron.  I may still have to replace but I'll research more.

I'm searching Bob's BMW and RealOEM using the part number embossed on my fender and nothing is found.  The embossed number is 46611453449 .  


The closest part number I can find is 46611456903 for a K75S.  Both the late model K100s, K75s and K1100s used Showa forks. I think fenders for these three models are interchangeable and the fiches bear that out but I'm not 100% sure.  Can anyone confirm before I commit to an Ebay purchase?

If it's ABS you could try to get a bumper specialist to plastic weld it. Alternatively and definitely cheaper have a crack at it yourself using a soldering iron. Beware of the fumes and use the correct filler material.
Regards Martin.

robmack wrote:I'm searching Bob's BMW and RealOEM using the part number embossed on my fender and nothing is found.  The embossed number is 46611453449 .  


The closest part number I can find is 46611456903 for a K75S.  Both the late model K100s, K75s and K1100s used Showa forks. I think fenders for these three models are interchangeable and the fiches bear that out but I'm not 100% sure.  Can anyone confirm before I commit to an Ebay purchase?

The part number in primer is 46612309731. As RealOEM shows it is the same part for all two-part Ks(*) as well as some R80s and R100s. 

(*) Except the K1

https://www.realoem.com/bmw/enUS/partxref?q=46612309731

duck wrote:

robmack wrote:I'm searching Bob's BMW and RealOEM using the part number embossed on my fender and nothing is found.  The embossed number is 46611453449 .  


The closest part number I can find is 46611456903 for a K75S. 

The part number in primer is 46612309731. As RealOEM shows it is the same part for all two-part Ks(*) as well as some R80s and R100s.

If the last digit in that part number were considered more likely to be an 8, then it would fit into the sequence of superseding numbers at realoem and would be found in the Max BMW parts index also.

That's a nine. Compare it to the six at the start of the sequence. If it was an eight, the proportions would be closer to the six.

Dai wrote:That's a nine. Compare it to the six at the start of the sequence. If it was an eight, the proportions would be closer to the six.

It could be an eight. Your comparison is not valid in all fonts, but your confidence is admirable.

Here are numerical example of four common fonts:

 
Notice the eyes of the eights and sixes of some fonts are have unequal dimensions; furthermore, the tails of the nines all end well below midline while the presumed tail fragment on the fender seems to be at, or above, mid-line. The sixes of the BMW font have unique ascenders; I couldn't find an example.

Regardless, consensus seems to be that robmack should find a replacement fender rather than devote time to repairing the broken fender when he could be devoting that time to making electronic boards and switch gear of one kind or another to help us keep our elderly motos functioning.

Maybe we should break out stereo microscopes but it's time for porridge and tangerines over here.

I have learned not to pay attention to the numbers on BMW parts as they often have no correlation to actual part numbers in the parts lists. 

Off the top of my head I would say that I have noticed that many molded plastic parts will frequently have strange numbers on them.  I suspect that these numbers may be part of some identifier system for mold cavities and tooling used in the factory.  By engraving a factory inventory number into the cavity it makes it difficult to misplace the tooling identification as well as giving traceability back to a particular tool or tool drawing if a manufacturing defect is found at a later date on a group of parts.  That this number is next to a date wheel makes me think this is the case.

Also, if a part has different numbers for applications on several different models and in different colors/finishes the molded in number may be used to access a list of secondary part numbers that identify the variations that are actually used. 

Bottom line is that I don't pay any attention to those numbers anymore.

Point-Seven-five wrote: Bottom line is that I don't pay any attention to those numbers anymore.

You're really missing something, Point-Seven-five. Start paying attention to the spaces within the numbers, like Dai and I are doing. It can be motivating.

Point-Seven-five wrote:I have learned not to pay attention to the numbers on BMW parts as they often have no correlation to actual part numbers in the parts lists.  ...

Well, I'll have to agree with you @Point-seven-five. I just contacted an eBay seller and confirmed that the part he has available has the same embossed number as mine.

robmack wrote:

Point-Seven-five wrote:I have learned not to pay attention to the numbers on BMW parts as they often have no correlation to actual part numbers in the parts lists.  ...

Well, I'll have to agree with you @Point-seven-five.  I just contacted an eBay seller and confirmed that the part he has available has the same embossed number as mine.

Don't pay attention to that number, robmack!

UPDATE:  I found a good used fender at Pinwall Cycle on Ebay and bought it.  I painted it and now it is being clear coated by a friend.

As for the original broken part, I attempted to fix it.  Since the fender is made from ABS, it can be chemically dissolved by acetone.  I could also use that liquid glue for plumbing, but I had acetone on the shelf.  I mated the parts and painted acetone along the crack, meanwhile holding the pieces together.  Eventually they bonded and I continued painting more acetone on the crack to saturate the surfaces.  Then, I dissolved a Lego brick in acetone to produce a sticky goo.  I spread this goo over the crack to bridge the two parts and filling in any small holes.  I let the goo harden and the repair looks pretty good.  So all I have to do is clean up and repair the top surface and I have a spare fender.

Nice job, Rob!  Your technique has been added to my memory banks.

Just be sure it doesn't lego when on the road.