Author Topic: WR500 Airbox repair  (Read 760 times)

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Offline poppabear

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WR500 Airbox repair
« on: February 28, 2018, 11:47:24 AM »

In the home stretch on getting the old girl back to new.  Here's a repair of my airbox that had a hole where it mounts to the frame (on the brake side).  It looks like the bolt was loose and vibrated until a hole was made.

Before photo:


Mount is Broken:


Close up of broken mount:


Filling with Epoxy:


Close up of Epoxy:


(to be continued...)

Offline poppabear

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Re: WR500 Airbox repair
« Reply #1 on: February 28, 2018, 11:51:53 AM »

This shows how the epoxy filled hole was covered, using vinyl spray.  The key is using the proper epoxy and the proper spray....

Epoxy is covered and blended:


Final Photo with the airbox installed in frame (photo of the opposite side, oops) :


Details of the products I used are available if anyone has interest....  Cheers.

Offline fred99999au

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Re: WR500 Airbox repair
« Reply #2 on: February 28, 2018, 08:21:09 PM »
I'd be interested in the product details and the longevity details. Not much will really bond with these plastics.

Offline poppabear

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Re: WR500 Airbox repair
« Reply #3 on: March 02, 2018, 01:27:39 PM »

Fred, let me answer the longevity question first - I honestly don't know...  Since the repair I've only run it about 1 hour after the airbox was repaired, and that was mostly break in and jetting runs.  So far so good.  I guess time will tell!

Product Details - The Epoxy I used is JB weld - Plastic Weld.  I'll get you the vinyl spray details shortly, it's way in the back of the cabinet and I can't get to it.

Process - Before I did any work on the airbox, it was cleaned very throughly and degreased.  The broken mount area was deburred, and the area around the repair (inside & out) was scuffed with 80 grit.  Painters tape was placed on the inside of the airbox to form a backstop.  Epoxy was mixed very slowly to prevent air bubbles, and very slowly added to the hole as shown.  Perhaps 5mm was also added around the outside of the repair area.  This was allowed to dry for 24 hours.   

Next day, tape was removed.  Epoxy was hardened and "welded" to the airbox!  More Epoxy was mixed and added to the inside of the airbox where the tape was located.  This was dried for 24 hours too.  I then drill the correct hole in the center of the repair for a new mount.  Then the repair was blended using 200/400 grit, cleaned and degreased.  Then, the repair area was sprayed with the vinyl spray.  It's critical to follow the directions on the can.  Otherwise, the coating will flake off quite easily. 

The new mount uses oversized washers (metal over rubber) on the inside of the airbox to distribute the pressure, and mounted tight for no movements.  Hope this makes sense...

Epoxy Used--



Process Used--



Offline gothamit

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Re: WR500 Airbox repair
« Reply #4 on: March 02, 2018, 03:43:11 PM »
Nice job
  FYI YZ/WR 125-250  1989-93 use the same airbox  ;)

   Bruce
1982 IT250J   1993 WR250  2015 YZ250FX

Offline Devondan

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Re: WR500 Airbox repair
« Reply #5 on: March 05, 2018, 02:14:50 AM »
If that doesn’t work Scotch weld do glue for HDPE, it’s not expensive, but the dispenser is! I’ve bought some but not tried it yet.

http://multimedia.3m.com/mws/media/961619O/3m-scotch-weld-structural-plastic-adhesives-8010-dp8010-blue.pdf

Dan
IT  400D - Trail riding
74 Montesa Cappra - Racing
YZ250 H - Racing
Norton ES2 500 trials
Norton 250 Jubilee - Road
Norton 350 Navigator (in boxes)
Norton 350 Single M50 (in boxes)

Offline poppabear

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Re: WR500 Airbox repair
« Reply #6 on: March 07, 2018, 02:21:13 AM »

Thanks for the heads up Dan.  I saw the Scotch weld product, but thought I'd try the JB Weld.  I've used their metal weld product many years, and have very good luck with it.  When the metal weld hardens up, it's ready to drill, sand, etc... and it lasts forever.  I thought their plastic weld would be just as good.

Let me know how the Scotch weld works out.  I can't afford the commercial system, but it does come in smaller tubes for guys like me.  Cheers!

Fred- still can't get the my cabinet to show you the vinyl spray that I used.... maybe one of these days though!