GS550E Urethane Rubber Boot Casting

[Guest]

All right. I've been mulling this over in my head for a while. There's no good source for new VM air box boots for the 550 series GS. I have some experience in casting parts with urethane rubber. Unfortunately, I'm not a chemist. Does anybody want to weigh in on the idea of custom casting VM airbox boots? I know that urethane rubber is not the best medium, but I don't have access to injection molding equipment for something like viton.

I bring this up because I restored my old boots late last year and they are already rock hard again. I'm not quite ready to make the leap to pods and this seemed an interesting idea.

[bobgroger]

Strange those are not available separately. How about one from a GS750 with VM carbs. Has to be pretty close, and it's only a $12 gamble for one. I'll bet a member might have one or 4 and is willing to send them to you to try?

[hampshirehog]

Strange those are not available separately. How about one from a GS750 with VM carbs. Has to be pretty close, and it's only a $12 gamble for one. I'll bet a member might have one or 4 and is willing to send them to you to try?

The rubbers from a 750 won't fit - they're much bigger.

[aclaytonb]

True story. Was hoping someone with a background in chemistry would jump in with some longevity stats.

[smilinbrad]

I restored a 550E two years ago. I didn't have any problem finding new carb holders. Over at the CX500 Forum we had the debate about casting new intake rubbers from urethane a few years ago. I think someone actually started to produce new ones from neoprene. I might also be confused!!

[aclaytonb]

CV carb boots are easy to find. Havent found a reliable source for VM carb boots, as the parts are not sold separately.

[Old Colt]

I would 3D print the parts in a flex material. There are a few variations of material but you will get good parts without the need to build molds. Yes a drawing needs to be generated which for some may be harder than making molds.

Would not a Buna N be a logical material for casting?

[aclaytonb]

Doesnt Nitrile, Viton, etc all take injection molding? Not super familiar with 3D printing.

[bwringer]

The carb/engine boots need to have excellent heat and gasoline resistance; they have to resist hot gasoline vapor, which will melt any material that can't withstand the heat in minutes. There are no know glues, goops, adhesives, RTV, etc. that will work here.

However, on the carb/airbox boots, the temperatures are not that high, and they only have to deal with incidental vapors. On the charts I've seen, urethane rubber has some resistance to gasoline (marked "good", but not "excellent").

So if you can work up a decent mold, casting new boots in urethane could actually work (again, only for the carb/airbox boots). And if there's any additive or alternate compound or whatever you can lay hands on to improve gasoline resistance, they'll last longer.

The challenge will be to create the pattern for molding. Old rubber parts shrink and warp very significantly, so you can't directly use an old one for a pattern. You'll have to sculpt or print something.

There's also a small market for airbox snorkels... for some damn fool reason, many of these are missing from shaftie airboxes, and the bikes won't ever run quite right without them.