With respect, those bikes may have ABS, they certainly wouldn't have grabby locky things on the rear, and if we are brutally honest they probably handle a lot better than our bikes at any speed. They probably don't have IRC rear tyres. They are on a well wetted circuit, not just after light to medium rain. No manhole covers and not a lot of white painted surface. Having said that, their skills are far advanced of mine.

I'm not a big fan of riding in the wet just because its WET and I also don't have a proper rain suit. But, every time I have ever gotten a new bike, I have purposely ridden in the rain to see how it rides and handles the wet. Sooner or later you WILL get wet unless you only ride on 'perfect' sunny days.

I had a bike years ago that when it rained, would die within about 5 minutes and wouldn't start again until it dried out. I never did figure out where the water was getting in and causing the problem.

The front end gets 'light' on the savage, it's much easier to lock the front wheel in the rain, at least on mine.  My back wheel, unlike most, doesn't lock at the meerest hint of braking.  They work like they should. It does lock easier in the wet, though.

The little ninja just keeps on going. Handling is not much affected at all. It will lock either end just slightly easier than in the dry. The tiny windscreen blows much more wind and water at my upper chest and helmet. It will slide easier in turns which is a little disconcerting until you find out just how much easier.

Like everyone has said, watch out for slick tar spots, manhole covers, steel plates, ANY painted surface, concrete is generally much slicker than asphalt. Bridges with steel grating are sometimes like riding on ice. Wind gusts in a storm will try to blow you around. Don't tense up.

You are much more a target in the rain. Nobody is expecting a bike to be out 10 minutes after it starts raining.  It's harder to see and harder for everyone else out there to see you. The cagers around here seem to have two speeds when it rains, barely moving or wide open. Practice wet riding in a controlled environment if you can...deserted parking lot, deserted back roads, etc. It won't take long to feel confident enough to go in the rain if you have to.

Wet smet!   The texas SOGGY BOTTOM BOYS RULE!... LOL.... miles and miles on the interstate in pouring down rain.....
And the handling...well, no one went down on the wet oily spot... lost a little traction, but didn't go down.... high five on that one!

Yeah... I slow down tons when it rains, and tend to spend most of my time really close to the line on the shoulder side of the road.... them cars and trucks like to play silly on you.

P.S.  I "thought" I had a great suit... Harley supreme rain gear...yeah.... wet is as wet gets..... wet ...... Even tried my military rain gear....same 'o, same o'.....

Usually play smart here in florida... if report says greater than 30 percent, I keep an eye on the sky.
I also keep three or four zip lock quart size baggies on the bike.... for the phone, wallet or any other accessories you keep on you.

Couple things a fellow biker told me to do in the rain...

Joe is in his mid 70s... been riding since he was a teenager. So he's been there, done that, got the scars to prove it.

1. Slow down.
2. Beware painted surfaces.
3. Turn your headlight to hi-beam.
4. If you have the chance, put on bright colored clothes to make yourself more visible.

Here's my current rain suit, and it works pretty darn well... and you can see it from a long ways off.  

http://www.amazon.com/dp/B0095CC390/ref=wl_it_dp_o_pC_S_ttl?_encoding=UTF8&co...

Every foreign object on the road starts to look like a banana peel to me when it's raining.  Dodge what you can and go easy on the stuff you can't.  

Dave's got the best advice of all...equip your bike with tires that can cope well. Pirelli MT66 are well trusted.  My rear tire slipped on oil when it was raining.  I was going 50 mph fully leaned over in a right hand curve.  I instinctively turned the front wheel in the opposite direction and the Pirelli grabbed at 90 degrees into the slide and put me right again.  I'll be putting those on in a month or two when my currents tires are replaced.

Tires, tires, tires. If you're slipping around in the rain like you're on snow then you need to look into new / better tires. I do some amateur car racing (autocross) and I had an old road racing LegGrand. Aluminum monocoque purpose built race car with a CBR1000RR motor. On a normal day if a Corvette ZO6 was running 60 second laps I would be at 51 second laps. As soon as it would start raining though I would get beat by Miatas since I only had Hoosier racing slicks with no tread. That's not even with standing water or puddles.

Not knowing the size that you need for your other bike I can't make the best suggestion but I always enjoyed the Avon Storms that I had on my ZZR1200. They took a lot of miles and I never had an issue with grip at any temperature whether it was wet or dry.