My X dearlership used it to wash the entire bike ( old one) and they left it on the bike too long. I had white spots all over it and they had one heck of a time getting it off. Almost ruined the paint. I would just use it on the wheels and lower engine. Wash it off right away with water and don't let it sit too long.

 

I use it full strength to clean the grime on beneath the frame.

 

As mentioned before, there is a simple green made for aircraft-

http://gsa.simplegreen.com/gsa_products_extreme.php

It is not cheap, but I use it on my bike, my vette engine, and other aluminum parts. I still don't leave it on too long and rinse thoroughly, but it does a better job on the aluminum parts and I'm not afraid if it gets on the paint.

 

I have used Gunk Engine Degreaser on painted and chromed hot rod motors for years to remove grime without any problems. Engine must not be hot (cool or warm is fine), don't let it dry or stay on more than 5 or 10 minutes. Rinse with a good stream of water till clean.
For small touch up, I have used 409 then work it in with an old 1" or 2" paint brush, then rinse. If it's not got much grime buildup to it, SG or 409 with the old paintbrush should do the trick.
On my bike, I spray 409 on any areas of concern just before I wash my bike - like around the oil filter area after an oil change.

 

Use it all of the time. My bike is a 2000 and the black portions of the frame looks brand new. I, like the others, do not allow it to sit for very long. When I do my only FULL wash on my bike, I spray 50% SG and 50% H2O on everything, let it sit for a moment and rinse completely. Then I re-wash entire bike with normal car washing soap and water. Looks great!

 

I guess I'm doing it wrong then. Ive been using SG on my entire bike for over a year. I only spray it on the bike when it is cold. I don't let it sit very long. I follow up with dawn soap in water and hand wash the bike. Rinse very well and dry with leaf blower.

My bike is Denim black also. Never cleaner and no spots or fading.

 

I use simple green on everything! Bike, quads, jet ski and cars. Full strength and use it on all metals and paint. It does not etch aluminum.

 

Been using for a long time, but only on engine and wheels. Works great for that.

 

+1
I've been using it for 10me years. Never any issues. As others have said, cool bike to start, dont let it dry on.

 

I was at a bussiness waiting for some freight an the shipper had an extra bottle......Guess I have a bike cleaner now!