My wind shield on my'12 RKC has the same rainbow effect mentioned above. I have NEVER used anything but car wash soap on the thing, and it still has the rainbow. I've got to admit though, when the CLEAN windshield is on the bike, I don't notice it. Actually, it is difficult to see.

 

I don't have that problem with Mothers detailer or Meguiars detailer also removes buggs quiet quickly.

 

Sometimes I wonder what all that "Harley Davidson, safe for windshields" over priced stuff costs. Butt not often........... I've always cleaned my windshield (& whole bike) with a mild dish soap & lots of water. After everything is clean I wax both the bike & windshield with Turtle Wax. No problems with colors, rainbows, distortions, smears, etc. Had a friend email me today about doin' the same to his windshield. He was happy with the results. Reminded me of goin' to 3 or 4 places to have the top replaced on an old convertible. Every one of them asked how I kept the plastic rear window clean for so long. None had ever heard of usin' Turtle Wax on 'em before..

 

+1 on the dish soap with hot/warm water on the windshield for bugs and cleaning... never an issue. I also use Pledge to completely finish the bike off, results are like wax but easier IMO.

 

Not to include any oily residue or other substance on the surface....

The rainbow effect is due to the way the polarized sunglasses alter/change the light wave pattern to reduce glare to the eyes. If you look at auto factory tinted windows thru polarized lenses you may see different patterns in the glass. The naked eye can not see the rainbow pattern because it only sees natural light waves.

The better plastic windshields that have a high percentage of UVA & UVB solar protection in it will also show a rainbow pattern when viewed using polarized sunglasses. The rainbow shows up more on a clear to lightly tinted shield vs the darker tinted shields.

The Aero windshield has high levels of both UVA & UVB formulated into the material to protect it from long term exposure from the sun.

 

I seconds the Hydrogen Peroxide. I mix it 50/50 with water in a spray bottle, spray it on shield and the bugs bubble up and then you wipe them off and leaves no residue what so ever!!!!

 

I had a FatBoy with a detachable shield, the ONLY thing I used on it was a towel with VERY HOT WATER... best thing to clean any windshield.

The shield lasts forever. Never put anything on a windshield but water.

The Electra Glide will only see hot water... (on the shield)

My 2 Cents

 

Its flashbacks from your youth. Bet you were warned that would come back to bite you in the ***....

 

I ride with Oakleys, and my polorized lens show what you were talking about, including on windows of other cars like Jim was referring to. With non polorized lens, the effect is greatly reduced.
Always keep in mind to take care of the coating on your windshield. I like to gently wet it first for bugs and stuff, let 'em get soft, and I use Plexus with clean microfiber towels. You want to avoid swirls and scratches. Be aware about anything that could scratch - even coarse paper towels.
The polorized glare thru the glasses are just a nature of the beast. No pilots will wear them, you can not function with them at all when sky visibility is critical. What we encounter on our bikes is much less than the reflective glare you get at 35,000 feet from the sun above and the clouds below with air traffic above, below, and beside you criss crossing at high speeds with a sleepy headed AT Controller deep into a long shift supposedly looking out for you.
Ride safe!