I had the same problem when i installed a 21' front wheel on my 09 street glide.The dealer tried balancing and every thing they knew.Anything over 60 mph the bike wobbles so much you feel like it is abut to throw you off.Finally one of the guys at tru-track told me to take the metzler tire off and try avon,he explained that the side walls on the metzler are soft which causes the bike to wobble,also to put 44-45lbs of air in the tire,instead of the recommended 30+lbs.
This cure the problem .......

 

check your pinch bolts on the trees. since you had the forks changed out, they had to have loosened the pinch bolts to pull the tubes out of the trees. loose pinch bolts will cause wobble.

 

Update.
Removed 21" front wheel and installed factory 2010 RG wheel. Absoultly no woble/shake at ANY speed. The bike has 2400 miles on it and have not ever noticed anything like this whatsoever. I've searched this topic and read 100's complaints with RG's, their new fairing placement, slowing down issues. My problem is ANY speed above 50MPH (with new 21" wheel and AVON tire) only. Also when I say it shakes, it really shakes. Guess I'm going to have to take it to the dealer tomarrow and check balance and trueness of this $1600 turd.

Like I stated earlier. PM claims the geometry is messed up by the 21" and that I need to lower the front only. Hate to run to the dealer and "cry wolf" on the service bulletin for woble. Going to contact Eastern Performance (where I ordered combo) tomarrow and see what they say. This $50/per hr. guessing game is getting old quick! Thanks again for the help and suggestions and PLEASE keep them coming.

 

Its a Head Bolt Issue.

Put a 21" on my 2009 Roadglide b/4 the 1000 break in service.
838 miles were on the bike when I switched out wheels and tires.

When I took the bike in for 1000 break in service,thech tightened the Steering Head Bolt and it fixed the 'Wobble'!

Fast Foward to 5000 and the wobble came back. So I dont believe it was my Wheel (RCComponent-Nitro) or the tire. But I did replace the Tire w/a Avon at 5000 miles and had 3 wheel weights put on the wheel.

My front end is completely apart rite now.In the next week I've got Chrome Uppers and Lowers bing put on. Mechanic is pulling the bearings and the races to make sure everything is seating properly.I'll report here, and everywhere if he finds sumthin 'Not Right'!

There has been allot of Head Bolt (steering bolts) issues w/the newer frames front end. Ya mite not have a $1600.00 Turd just yet!

My wheels and tires were also bought from Eastern Performance.

 

Maybe not the same here but i put on a 19" with a avon cobra tire and had a bad wobble around 35 and above, to make a long story short i put another cobra on it and it cured the problem. good luck and let us know how it comes out!

 

update.
Got my mechanic and Eastern Performances mechanic on the phone together. Both decided to check balance of wheel and tire combo. Balanced out fine. Suggested he retighten "neck bolts"or whatever they are called. Using the swing away (?) method with new wheel and tire mounted. It is and was within the correct spec. E.P. suggested my mechanic call Performance Machine. They still claim I should lower the front only of the bike. Going to pick the kit up tomorrow and pay for another experiment.

 

My money is on a bad tire!!

 

Well bike was lowered today using the HD kit on the front. Actually made the woble worse. Think its about time for Eastern Performance to send me a replacement and start refunding some money on labor and parts due to their incorrect information and defective product. Here is a link to a pic of the bike since I cant seem to get it to just show the actual picture,

http://i69.photobucket.com/albums/i5...iggins/090.jpg

 

You'll be good to go after a new tire install!!

 

It also happen to me , dealer adjust the neck bearing and it goes away . also check air pressure .good luck