Plastic Motorcycle Fairing Repair

asechrest

asechrest

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asechrest
My current project is a little 2 stroke motorcycle. Looks like this (not mine):

derbi-gpr-50-r-race-replica-1.jpg


This is a Spanish manufacturer (now owned by Piaggio), and the bike is no longer imported to the US. It makes getting stock replacements either expensive or impossible. Luckily, the engine appears to be fundamentally sound and I have it running (75cc single-cylinder factory upgraded engine, 2 stroke).

A number of the fairings are cracked (with crack extending to the edge of the piece) or have entire sizeable chunks missing. The fairings appear to be a relatively thin plastic. Anyone have some suggestions on how to repair the cracks and how to "rebuild" the missing pieces of the fairings (would fiberglass work)?

Thanks. :)
 
Depending on how bad it is, you can weld it with a soldering iron.

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Use the parts as plugs and make molds to lay up new carbon fiber parts.
 
plasti-weld...?

I have tried fiberglass repair, was not awesome, could be the bad mechanic though (me).

I have a ysr50, we'll have to race sometime!

:)
 
Don't have any photos at the moment but one thing that unfortunate is that on at least one of the fairing pieces, the chunk that's missing includes the edge of the piece. So it's not so much a hole as a bite out of a pizza, for example. Said fairing has symmetry so I know what the shape should be, but I have a feeling that somehow rebuilding the piece is not an easy job.
 
StevieTimes said:
plasti-weld...?

I have tried fiberglass repair, was not awesome, could be the bad mechanic though (me).

I have a ysr50, we'll have to race sometime!

:)
Click to expand...

Sounds fun! This was set up as a track bike I think. It's got the 75cc engine (regular was 50cc), upgraded Dellorto 21mm carb, and performance pipe. I'll be taking it to a kart track soon with a guy I met on a forum who happens to be local to me and owns a bunch of Aprilias.
 
Here's a good Youtube video series about making a plug, then a mold, and then a part. You're ahead of the game since your part will serve as a plug. There are lots of good videos about in Youtube.

 
It is totally repairable, assuming ABS plastic. I've had ABS fairings repaired before to as good as new(on the outside). You just need to find a shop that does it. This is an example: http://www.sportbikeplasticsrepairs.com I would ask around motorcycle circles. Stickers would probably have to be recreated though.

Missing parts would be a bigger problem, you may have to order it from EU since you have no mold
 
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Airtech makes fiberglass reproduction panels for it..

I've got an Aprilia RS50 with a 70 kit in it, tons of fun!
 
FredFenster said:
Airtech makes fiberglass reproduction panels for it..

I've got an Aprilia RS50 with a 70 kit in it, tons of fun!
Click to expand...

Thanks, and you're right. A bit spendy but actually cheaper than the stock fairings that are available from overseas. No mounting holes, though, but should be easy to drill.

I like the Aprilias, too. I actually like the fit and finish and chassis of the RS50 better than this Derbi. I've been dreaming of upgrading to an RS250 after I've had my fun on this Derbi.
 
RS250? that's a serious bike!

My YSR50 is punched out to a 60. Currently not running, the gas tank rusted inside like... I don't know, something really rusty.

We should have a POA GP! If you're not betting on me, you're wasting money.

(yes, that was the start of the trash-talking)
:)
 
StevieTimes said:
RS250? that's a serious bike!
Click to expand...

Yes, I tend to get way ahead of myself. :)

StevieTimes said:
My YSR50 is punched out to a 60. Currently not running, the gas tank rusted inside like... I don't know, something really rusty.

We should have a POA GP! If you're not betting on me, you're wasting money.

(yes, that was the start of the trash-talking)
:)
Click to expand...

Replace that tank and let's do this.
 
asechrest said:
Replace that tank and let's do this.
Click to expand...

I usually assume I'm the fastest guy in the room. I have been proven wrong several times. :)

Old man Gary Nixon was one of them. Thought I'd have something for the guy...
 
When I used to race ATVs, every wreck would break some piece of plastic. If it was an expendable piece of plastic ( front fenders being the primary example) I cut it off. If it needed to be on there, I drilled small holes along either side of the crack and zip-tied it like stitches. I tried plasti welding and never had much success, but then again it was getting flipped off of doubles every third weekend.
 
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