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Hi,

this happened to me second time now, by accident I have cracked the small plastic piece in the middle just above the headlight. How would you go about fixing it without getting a new cone fairing? I have tried a few things before but nothing seemed to hold it good enough.

Thank you.
 

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Plastics can be tough to repair but I've had success repairing my belly fairing when the exhaust burned a bubble in it. I used epoxy resin and some woven fiberglass cloth to reinforce the area on the back. I scuffed the plastic very well and cleaned it with acetone. Several layers of the epoxy/cloth did the trick and I used some body putty on the front surface. Primer and paint finished the job.


Eric
 

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Building up layers behind that piece will interfere with the fit of the windscreen.

Personally, I would take it to someone who does plastic welding.
 
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I've had a play with plastic welding with some success - albeit not in areas as directly visible as that.

You can buy proper kits but you can also get very good results with a soldering iron and cable ties ;) I bought a cheap fairing from ebay to practice on and then had a go for real.

Alternatively, have a chat with a car body repair shop - they will have experience on repairing plastic bumpers etc and will also be able to paint for you.
 

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Bigger question is "why does it keep cracking?". Unless you are experiencing impact, as in a crash, that part should not just "crack" on its own. There may be some stress in the mounting, a bent stay perhaps, that is causing the crack to form.

You need to determine what is causing the crack in the first place, or you will keep having it occur.
 
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These usually crack when individuals remove them from the bike and then remove the windscreen. That windscreen provides a lot of support and prevents twisting which is what usually breaks that thin bridge.
 
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Don’t know what it is like in your country, but here we have bumper (fender) repair shops that repair that sort of thing, then follow up with a chip repair service with an airbrush for the paint repair.
 

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These usually crack when individuals remove them from the bike and then remove the windscreen. That windscreen provides a lot of support and prevents twisting which is what usually breaks that thin bridge.
Wow, seems I got lucky when doing mine. In other words be very careful when doing it?
 

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You have to experiment with perhaps some test pieces from another bike since not all plastics are the same, but I have fixed both glass and plastic fairings using the following procedure:

1) lightly "V" out the crack front and back with a Dremel tool and a cone bit. The opposing sides of the crack should still meet, but there will now be a "valley" halfway through the fairing on front and back along the crack.
2) fill the crack front and back with 1/16 fiberglass strand - I use the stuff from Fiberglast https://www.fibreglast.com/product/116_inch_Milled_Glass_Fibers_29/Fillers
Aircraft Spruce also has this stuff https://www.aircraftspruce.com/catalog/cmpages/milledfibers.php but they don't note the size
3) make sure that the glass strand is packed firmly into the "V" and is slightly proud of the surface of the fairing
4) Flood the packed glass strand with thin cyanoacrylate glue, also known as super glue - I like this stuff https://www.zapglue.com/ca
5) block sand the area level and apply more glass/CA if needed
6) fill, prime and finish the entire part
 

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One thing I neglected to mention is that you should first very lightly tack glue the joint - perhaps in this case at either end and with it in alignment - with what is known as "medium" CA which is a thicker variant of the thin stuff. In this way, the joint will be stabilized and can withstand the packing of the strand. Avoid filling the joint entirely with just glue alone - it is the glue/fiber matrix working together that provides the strength.
 

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Wow, seems I got lucky when doing mine. In other words be very careful when doing it?

Yes.

Just a side story: I was fixing up and F4 750 EV 03 and I needed a front nose. I found a perfect nose for a great price. The guy shipped it to me in a nice box full of packing material but no windscreen or support for the area where the windscreen goes.

The fairing showed up with that little bridge cracked. The guy was an upstanding gent and refunded my money and told me to keep the fairing. If I ever repair it and sell it, I will give him his money back. Right now it sits in my garage as a reminder.
 

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Hello

I have a guy that can fix that! He did two front fairings for me. He did a OUTSTANDING job! At the moment he is doing a rear tail for me as well. Let me know if I can help out.
 

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I removed the windscreen which was a mistake looking back at it. It fell from around 1 foot height straight on the nose and cracked. So keep that in mind when you are changing the windscreen. Is your guy located in the UK?
 

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Hello

I have a guy that can fix that! He did two front fairings for me. He did a OUTSTANDING job! At the moment he is doing a rear tail for me as well. Let me know if I can help out.
In the interest of knowledge sharing, do you know what he did to fix them?
 

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He lives near Jacksonville North Carolina. But I don't know how he does but I definitely recommend him. I will have to put up pictures when I come back from vacation.
 

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I've done a similar repair in the past. If that's ABS plastic you could easily repair that by using a soldering iron on the underside of the crack to weld it back together (use tape on the outer side to hold it in place while performing the weld). Then use filler material (a light application of bondo) to get the girth back. Sand, spray (color + clear), then compound.
 

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The type of plastic is key to the repair. In any case of plastic welding you will need filler material. If that material is not compatible with the plastic of the fairing, it will not hold.

There have been many discussions in this forum about the material used for fairings. The manuals say Thermoplastic Material and that is any plastic that can melt and flow.

I believe that our fairings are polypropylene, but that is difficult to pin down.
 

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I believe that our fairings are polypropylene, but that is difficult to pin down.
In my experience with body materials on vehicles, I do not think MV fairings are polypropylene... not based on what I know. ABS maybe. Polypropylene is very soft and flexible and does not crack easily...or accept paint coatings easily.
 

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Yikes. I meant to say Polystyrene....
 
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