System Case Repair

Well, the unmentionable happened. I dropped the bike while stopped. Let myself get distraced with unfamiliar surroundings before getting control at the stop. Got lucky: the only real damage became apparent later - system case came off the lower mount, rubbed up against the rear tire for a few miles or so before I relaized what happened.

Tire melted a hole into the system case, about 4"long by 2" high.

I was thinking about trying a fiberglass repair. It doesn't have to be real pretty, as it's not a visually exposed area.

Any thoughts?

Thanks,

Tony

You could try making a patch out of Kydex. It's a thermoforming material used to make holsters and knife sheaths. Cut a piece large enough to cover the hole, warm it with a heat gun and lay it over the opening. It will form to the contour of the case. When it cools I'd use a silicon glue or construction adhesive to attach it. Pop rivets could be used to reinforce the patch.

Kydex is tough and easy to work. I found a number of articles on the web explaining how to work it.

I bought a sheet of the stuff from these guys:

http://www.knifekits.com/vcom/index.php?cPath=41&osCsid=fc81bef290077d3068d74b41ead165dd

Forget fiberglass ... Kydex, or even plain old ABS sheet material (not as strong, but certainly strong enough) would be the way to go.

I don't think I'd use pop-rivets though because 1) the holes will be a starting place for a crack to begin, and 2) pop-rivets expand as the mandrel is withdrawn, again, causing unwanted stress, and cracks.

Craig Vetter has a killer 2-part adhesive available on his website; it's called Versilok?« and it is a "structural acrylic" material ... very strong, stronger in fact than Kydex, or ABS. And it's thick ... peanut butter thick, so it will adhere to vertical surfaces and fill gaps (up to 3/8" gaps if need be). We used to use it to bond the inner and outer shells of the Windjammer fairing together. It was originally formulated to assemble flight surfaces on the F4 (no rivet holes to propagate cracks).

Craig sells it as the "Hotcha Repair Kit" and it includes ABS material as well. Not cheap, but you'll know for sure that the adhesive isn't going to fail.

Alternately, ABS or PVC pipe cement will bond Kydex or ABS, but it will be messy since they are so thin, and it will not fill any gaps.

edit -
Tap Plastic is another good source for sheet plastics.
This may be a suitable alternate to Versilok.

Can you give ua a shot of the damaged area?

abcor59 said:

Well, the unmentionable happened. I dropped the bike while stopped. Let myself get distraced with unfamiliar surroundings before getting control at the stop. Got lucky: the only real damage became apparent later - system case came off the lower mount, rubbed up against the rear tire for a few miles or so before I relaized what happened.

Tire melted a hole into the system case, about 4"long by 2" high.

I was thinking about trying a fiberglass repair. It doesn't have to be real pretty, as it's not a visually exposed area.

Any thoughts?

Thanks,

Tony

Click to expand...

I had a cracked system case. Tried fiberglass- not good; tried 'glue'-not good. What worked is plastic welding. I found a shop that specialized in all sorts of polystyrene fabrication. That was the answer and that long crack never broke open. That was about four years ago and it lasted..... well, at least until two weeks ago when I lost that case somewhere in Maine - Bob

After making my post regarding Kydex, I remembered these guys:

http://www.urethanesupply.com/

They specialize in plastic repair products and their web page has several step by step guides for repairing such items as plastic radiator tanks and car bumpers.

It seems like the toughest part would be identifying the plastic.

I've never used this company or their products but the web site is a great resource.

It seems like the toughest part would be identifying the plastic.

Click to expand...

After thirty-five years in the business I still have a tough time identifying these materials without a lab analysis, but this is basic guide to identifying "plastics".

All "plastic" products are manufactured from what is termed a "resin". Resins can be either a liquid (i.e. polyester and epoxies) or a solid. In the case of solid resin, it is heated to the liquid stage and injected into molds (to make specific parts), or extruded into sheets which are then re-heated and formed. And just to make it more confusing, solid resins start out as liquids...

The two basic types of "resin" supplied to manufacturers:

Thermo-PLASTIC materials like, Kydex, PVC, and ABS (acrylonitrile butadiene styrene) as used on Vetter fairings, Krauser saddlebags, and many motorcycle body parts ... melt. As a result they can be heated (at a lower temperature) and formed... reheated and formed many times. In pelletized form they may also be heated (to a higher temperature) and injection molded. These plastics can be bonded with a number of adhesives. The identifying test is: take a sample and heat it (a hot air gun will work).

Thermo-SET materials, like "Fiberglass" can not be formed by heating. They can be deformed by heat, but they will not "melt". The key word is SET; the liquid resin (polyester or epoxy) are cured (hardened) by the addition of a catalyst; the curing phase can be accelerated by heat. They all utilize a "filler" in suspension in the resin (glass fibers, minerals, etc.) to add strength to the matrix. Many of the body components on low production-volume motorcycles use this material/process because the tooling is relatively inexpensive. They can be bonded with a number of adhesives including structural acrylics and epoxies. The identifying test is: it will not melt and shows signs of a filler material (fibers).

Polypropylene (as used on old Vetter bags, MX gas tanks, dock floats, etc), is also a thermo-plastic material. It has a characteristic "greasy" feel. It can not be reliably bonded with the "usual" engineering adhesives due to it's chemical nature; repairs are generally made by welding. Specialized adhesives are available and require extra surface preparation steps to bond reliably.