Shimmy in front end at 70 mph

Exactly as topic, my bike cruises smooth as can be but once you get up to about 70 mph...theres a pretty noticeable shimmy in the front end. Enough to make me back off the throttle a little and start worrying. What could it be, wheel bearing about to go out? Dead forks? Any suggestions?

what kind of bike?tire,wheel bearings,steering head bearings.lots of differant things.have you done anything to frontend?:whistle:

Personally i have't done anything, i've only owned it for about 16 hours now...LOL. Visually the only thing i can see wrong is the handlebars are a little bent up on the right side from what looks like a fallover accident. That shouldn't cause a shimmy though, the forks do seem a little dead when i hold the brake and press down on the front. It seems like theres a soft spot in the center of the travel, followed by a little thumping noise. Type of bike is in my sig.

BTW i got those pics of the carbs for you in the carb section, plus one of the whole bike in my new member thead.

If the handle bars are bent the front forks could be out of wack. Could be as simple as low tire pressure too.

Visually the forks look straight, but i know that even a fraction of an inch off will cause some vibration. Im going to check it a little better after i take care of the mechanical problems.

same exact thing is happening with my 750. it was in a wreck last year, so it now has a 550 triple and forks, forks were re-done(fork seals and oil), new tapered steering bearings, new wheel bearings. put it back together and the bars start wavering side to side around 70mph. took the front end apart again, tightened the bearings up more, they were a little loose I think, put everything back together. it's been raining so I haven't test ridden it yet. I think if that doesn't fix it I will start looking at the rear shocks and swingarm bearings. I need to verify the run out on the front tire as well, but I think it is in spec.

could be as simple as the tire out of balance also

wireman wrote:

what kind of bike?tire,wheel bearings,steering head bearings.lots of differant things.have you done anything to frontend?:whistle:

maybe it will smooth out at 100

Fork, singular.
Handlebar, singlar.

Your front end was most likely tweaked when it fell over. It could also be worn steering head bearings. You'll want to disassemble the whole thing, press in new tapered roller steering head bearings, then reassemble the whole thing with proper alignment and torque, and a new handlebar. I'd also recommend replacing your wheel bearings while you're at it, and I'd highly recommend a fork brace.

It may sound like a lot, but this way you'll know what you have in it... I did all these things, including new tires, and my bike rolls straight and true at all speeds (including those speeds that would get me locked up).

guitargeek wrote:

Fork, singular.
Handlebar, singlar.

Your front end was most likely tweaked when it fell over. It could also be worn steering head bearings. You'll want to disassemble the whole thing, press in new tapered roller steering head bearings, then reassemble the whole thing with proper alignment and torque, and a new handlebar. I'd also recommend replacing your wheel bearings while you're at it, and I'd highly recommend a fork brace.

It may sound like a lot, but this way you'll know what you have in it... I did all these things, including new tires, and my bike rolls straight and true at all speeds (including those speeds that would get me locked up).

So how much money are we talking there on the bearings and such. Roundabout price.

before you get all excited check the simple things first;) good tire?does front wheel have any weights on it?might need to be balanced,jack up front of bike enough to get front wheel off of ground grab bottem of wheel try rocking wheel while holding forks in one place,grab wheel try pushing front to rear any noise around steering head?if you have to take front wheel off to change or balance tire check/repack wheel bearings and replace seals at same time.

wireman wrote:

before you get all excited check the simple things first;) good tire?does front wheel have any weights on it?might need to be balanced,jack up front of bike enough to get front wheel off of ground grab bottem of wheel try rocking wheel while holding forks in one place,grab wheel try pushing front to rear any noise around steering head?if you have to take front wheel off to change or balance tire check/repack wheel bearings and replace seals at same time.

I don't recall seeing any weights on the wheels, front or rear. I was just trying to get a worse case scenario on cost for the front end. Im deffinitely going to check for the little things first.