GS450t- stupid newbie question

[earlfor]

Riding is a skill that anyone can learn. If you take a class, practice and build on the skills in stages, there is no reason to expect to become a statistic.
I've been riding about 40 years and have owned a bike for 35.
I havent dropped a bike since 1976 and I dont intend to refresh my memory of what its like. :-) I cant say that I am alway sane, but I do always do my best to remain within my skill level. Riding is a great way to to enjoy a day, and I wouldnt do anything else. Just remember, the future comes at a rate in proportion to how far you twist your right hand. You're the one driving. eheh


Earl

Thanks for your patience and help. I hope I can ride this without killing myself.

When I was 18, speed was the only thing important to me, and frankly, owning a motorcycle would have been a horribly bad idea. Now, I can potentially ride like a sane person and be a little more sedate. ANd I have a lot of twisty country roads nearby, so I look forward to a fun(er) summer.

[themess]

RTV means "Room Temperature Vulcanizable". Most curable (vulcanizable) polymers must be heated to around 400F for about ten minutes to cure. Sulfur is a common curing agent, either as raw sulfur or in other compounds that release suflur when heated. "Accelerators" are other chemicals needed to cure the rubber this quickly. Without accelerators, vulcanization can take hours or days. During the curing process, the rubber emits gases which will turn the part into a sponge unless it is held under high pressure until the part is completely cured and cooled.

(Curing or vucanization is the process that changes the polymer so that, when it is deformed, it returns to its original shape. Chewing gum is very soft, uncured 'gum' rubber.)

Different chemistries can cure many polymers much faster, and even at room temperature. Some are cured by adding a hardener, and others react with either oxygen or moisture in the air to start curing.

So far, I've talked about the "cure system", not about the type of rubber or polymer that is being cured. The type of polymer is critical to what temperatures and solvents the cured part can survive in, while the cure system makes only a small difference.

The gold standard for heat and gasoline resistance is fluoroelastomer, or fluorocarbon rubber. The trade names for this are Fluorel (3M) and Viton (DuPont). 3M is the older and bigger company in this business, while DuPont is better at marketing. If I were back in the rubber business, the only way that I'd use DuPont is to bargain with 3M to keep prices down.

Nitrile rubbers are much more common for heat and solvent resistance. They cost a lot less, and are easier to use. But they don't work in extremes. Some silicones can also be good, but their mechanical properties are terrible. There are also several other types of solvent and temperature resistant curable polymers. And fluorocarbons, nitriles and silicones are all large families. It isn't enough to specify "metal", we also need to specify "steel" and then the type and grade.

The same applies to "RTV". Saying "RTV" works or doesn't work is akin to saying that "metal" works or doesn't work. I've never tried to replace a gasket with any type of RTV, but I've known people who routinely replaced paper gaskets with some type of RTV without any problems. Paper gaskets cost less than a solvent resistant RTV, and assembling an engine with a paper gasket should be faster than using an RTV gasket.

Just my two cents worth.

Tom (former rubber chemist)