Replacement plastic bodywork for early sportsbikes can be expensive and often unobtainable, so repair is usually the answer. You know the feeling. You’ve tracked down the bike of your dreams – the bike you longed to own in 1989.
It’s not a million miles away from being clean and tidy, looks to be a fairly straight-forward resto and even the price is sensible. Sure, the bodywork’s a bit tatty but hey, you should be able to pick up some better panels easily enough. Right?
Wrong. New-old-stock bodywork for most ’80s and ’90s Japanese classics is hard to come by – and very expensive. Luckily, over the last 10-15 years, plastic repair technology has come on in leaps and bounds and what was once scrap can almost always be repaired to look as good as new.
First choice is plastic welding. Most motorcycle bodywork prior to 1997 is ABS, which is easily welded with the right kit – and technique. Many post-’97 plastics can be welded too, but check with a plastic repair specialist first.
Tools For the Job : Some broken panels to practice on. Hot-air gun with welding attachment. Correct type plastic welding rods. Grinder. P36 disc. Solvent cleaner. Plastic adhesive. Flexible plastic filler. Plastic mesh. 120 sanding sheet. Stiff paper or card. Masking tape.
You need to heat both sides of the joint and the filler rod to just the right temperature so that they all end up melting at the same time. When they set (this will take seconds), you’ll have a strong, permanent bond that will be as strong as the original panel. Plastic welding is done with a specialised hot-air gun, with a guide that’s used to feed filler rod into the joint.
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| The first thing is to close up the split as much as possible and hold it securely with a clamp. Don’t worry about marking the panel, because you’ll be filling and re-finishing it later. |
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| Get the grinder out and use it to remove all traces of paint from the surrounding area. Plastic will only bond with plastic so the area you’re working on here will need to be bare plastic. |
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| Open the top face of the split to form a V-shaped channel a couple of millimetres deep using a grinding wheel with a P36 disc. This will allow the filler rod to sink into the joint and make a strong bond. |
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| With the heat gun up to the right temperature (different plastics have different temperature settings – practice on an old bit of broken fairing first), start to run the filler rod into the joint while drawing the gun along it. One hand guides the gun while the other feeds the rod through the guide. |
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| You can see how the weld has penetrated the joint from the reverse of the panel but, for maximum strength, repeat the process on the rear of the split. Remember to clean the panel off thoroughly with a grinder before welding. |
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| If you have to go around a curve in the panel, it’s probably best to finish the ‘flat’ weld first before starting again on the curved run. Lift the gun off the joint and leave the surplus rod in place. You can trim it back with a pair of side cutters after a few seconds. |
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Grind both sides of the joint flat, which will remove any filler rod standing proud of the joint. After this has been done, you can step back to admire your handiwork. Once you’ve sorted a bit of filler and done the finishing, the job’s a good ’un. |