I am new to the forum and hope I am posting in the proper location. I have a 2012 Street Glide with several mods. I first had the engine bumped to a 107 with about 120hp to the rear tire. Plenty of power and stable for the long ride. Anyway, my luck, I found an idiot talking on a cell phone who ran a red light straight in to me and caused about 15K damage to the bike. Luckily, I was able to walk away.
Anyway, in rebuilding the bike, we did several mods on it to include a 21 inch performance machine front wheel (factory width), wrap around fender, single caliper brake, and blacked out front end. The rear tire is stock with Metzler tires on both. We put Progressive drop in shocks in front and lowered it to make bike level (just over an inch). Still have the stock rear shocks for now. Also, had to put a slight rake (using a stock trike triple tree; raked out about one inch at the bottom) to handle the size difference in the tire.
The bike looks great; however, at high speeds, it develops a bad wobble. Right at 100mph, the front end gets loose and wobbles BAD. Not until that speed, but what's the point of having all that engine if I can't use it when I am in the mood? I have seen several suggestions but wondered if anyone had a similar mod with the same problems. Any suggestions would be greatly appreciated.

 

Damn, a wobble at any speed is hairy! I believe I've read on here that the batwing fairing does create lift at higher speeds. Could that be it? Did it do that before all the mods?

 

Damn dude, youre one lucky ****. But welcome to the forum. I dont know what to say about your wobble situation other than the fact that you may have a bunch of issues stemming from the accident that could cause the wobble issue, and changing the rake, 21" wheel and lowering it could compound the symptoms. But any way you came to the right place for info, someone else will be along to give some advice.
BTW what mods did you do to get 120 hp?

 

Stock front end here.

Progressive 940's in the rear.
Progressive Monotubes in the front.

No issues.

 

There is no need to rake the triple trees for a 21" wheel. My guess is the raked tree is what is causing the wobble. Take the raked tree off and put the stock tree back on and the wobble should disappear.

 

 

I've read somewhere that those funky windshields like the Extreme from Long Ride Shields create some down force. LRS are good people with a good product and good service. Who knows the might send you a shield to try at 100mph; kind of like being there test dummy (lol). Klockwerks also make one but not sure what it's called.

 

At that speed, I would think that tire balance would be critical-everything would be critical. Tires balanced, checked for roundness (or out of round if you prefer) lateral and radial run-out of both the tires and wheels. Finally to the "standard" recommendation, steering head bearings. If it were me (and I have already done this even though I don't go that fast) is to tighten the head bearings to absolutely the tight side of the tolerance, if not a bit tighter.

Part of the advantage of all that power is do well in stop light drag races and to be able to comfortably pass when you want to, but where can you go 100 mph without at least exposing yourself to an all expenses paid trip to jail? Perhaps this should be like the old joke: Guy goes to the doctor and tells him, "it hurts when I do this". Doc answers, "Don't do that". If the wobble hits at 100, perhaps 98 is close enough.

 

The Klock Werks is called the Flare. You can check on www.kustombaggers.com to see if your local dealer has the Klock Werks test ride program. I just tried one last week.

As for wobble, everyone's advice is better than mine as to why it is happening. All I can say is that my 2012 all stock Street Glide does not wobble at 100+ MPH.

 

With a crash bar and lowering the front end to level the bike, the 21 inch tire would hit the bar if I hit a bad bump. I didn't want to rake much so the trike triple tree was the way to rake it the least. Was told that should help with the front end stability not make it worse. Obviously, not mechanically inclined, so just seeing what everyone else has tried.
No wobble before the front end mods. I am sure it has something to do with the size of the front tire but that mod has been done for years so I figure there is a fix so I can keep the look I want and the performance. I know with the older chassis this is not an issue (so I've been told). Obviously if I can't get the wobble fix, I will just have to go back to the stock configuration.
I read where the Metzler tire is a 2 ply tire which may not be heavy duty enough with the mods to handle as to where if I change to a different tire it may fix the issue. Any thoughts?
I can't say exactly what is in that engine. My mechanic is awesome with engines. All I know is that it is a 107 build.