996er

Got my bright yellow 996 a couple months ago from a dude that crashed the bike. Mostly plastic damage and a nice dent in the tank. The guy said he laid it down on its side and the bike slid into the back of a car. Forks were pushed up a bit, so I readjusted them flush with the triple tree. I replaced the left side clip on, pegs, bar ends, and a couple other small things that were bashed up. Retorqued and adjusted everything to spec and got a new tire. The forks are straight with no visible damage. The bike gets shaky at about a hundred and if I take my hands off the bars at lower speeds will shudder a little here and there but nothing too crazy. Wen I hit bigger bumps doin about 80 it shakes like all hell...tank slapper style. Does anyone know if I should replace the steering head bearing and the wheel bearing too? If anyone has had similar issues let me know wht you think. Thanks.
-J

nuhawk

I think your forks are busted up. Unequal compression over the bumps could cause the rotation of the bars as you describe. But really, Dude - this is like an allergy. If it shakes at a hundred - drive nintey. If it tank slaps over the bumps - find a new road.

996er

Yeah I drive my bike like ghost rider on the highway on occasion. It just feels wobbly over bumps and at higher speeds tank slappin if I dont hold on tight. Even in a straight line around 100 starts to bobble back and forth for a second. Could the compression get messed up and the forks not be leaking? Can I get the forks checked to see if theyre outta spec?

inderocker

Take the forks out of the clamps and clamp the lower in a vice. Rotate the tube while it's attached to the lower and you should see it wobble as you rotate it if it is indeed bent.

nuhawk

Hawkrider can help you with this. There is a company in Boston that will true forks to better-than factory tolerances.

He is an ugly bastid and expect to pay dearly. Although, recently, he seems to respond best to posts that begin with, "Hawkrider, I love you."

drew_c14

Unequal compression sounds like a winner to me. How many miles were on the bike when you got it? Could be the forks are in need of some TLC, new fluid at the least.

MotorToad

Unequal compression damping has nothing to do with anything. Many bikes have compression damping on one fork and rebound in the other. That's not saying there isn't a problem, though.

First, I'd look at the rear tire. If it's very squared off (and I think it is) you'll get mad wobbles from it. After that, look at wheel bearings and steering head bearings. Hell, it's been wrecked, you should replace those anyway.

trinc

rear tire ? never seen that ( felt that ) i'd check the front tire... not just for balance but also for cupping. i'd also spin the wheel off the ground & look at the rotors. double check the tire pressure.


front forks flust with the triple ??? that 'may be too high'. they need to be at the retaining clip.

also double check the manual with the proper procedure to tighting the front pinch bolts.


tim

996er

Youre right. My back tire just started showing threads today. I ordered the new one. The front I just put on a Dunlop Qualifier. Rotors are good, new front wheel is balanced, forks are torqued to the manual specs and procedures. Im gonna see what happens with a new rear tire & front wheel bearings and go from there.
- J

PUSHrod

You might want to try in the free or cheap column first, make sure that the alignment of the wheels are perfect and that the swing arm is not tweaked, then retorque the pivot bearings for both the swing arm and triple tree. From the prang you described, there could be an out of tolerance runout on the front wheel.

Wobbles and tank slappers can be scary, 'luck out there.

MotorToad

If the rear tire is basically flat (you get that more often in Florida than other places), it basically bounces back and forth off the edges. Picture the tire: \_/ when it weights the left edge, the bike's c of g is to the right, and it falls over to the right, weights the right edge, and so on. When you're riding you basically damp this action out, but with no hands (as OP mentioned he did) it's free to wobble. At some speed (45 mph on an EX500) it's going to find the resonance of the front tire & forks and slapping starts.

Hotbrakes

Steering Stabilizer!
Definitely check the forks, lower the front a little probably, and put on a stabilizer. Only took one good near launch from a tank slapper at 110mph for me to get one.
Landing wheelies wrong can cause wobbling too. The last thing you want to do while wheelying away from that pesky patrol car is crash.

996er

Haha. I know what your saying about the shake when puttin the front wheel down a little to hard. No more crashing for me thank you. Memorial day 2007, some idiot made a complete stop in the left lane of a 50mph road to try and bust a u-turn right in front of me doin about 60. I did a nice 50 mph endo into the rear of his SUV wearing a tshirt on my ninja ZX6. Ouch.

nuhawk

The front end of a Superhawk is so squirrelly in its stock config it's not funny - it's deadly. I did the brakes first only to find out the forks were just as bad. I crested a hill out in county on last Sunday morning and thought I saw a cop. At 110 these guys take prisoners, especially on Sunday morning. I over reacted and plowed on the front brakes. No, I didn't do a stoppy at 110 but I have never heard them scream like that. I dropped 40mph in 2 seconds. The front end didn't plow, it didn't wiggle, it did dive in a little harder than I would have liked but it was like an arrow on the road. Turns out it was some other car with a similar cop car paint scheme. Thanks to gixxer six-pots, HH pads - well broken in, ss lines and Nemish front end suspension on top of Pilot Powers. When you can laugh inside your helmet you know it's good.

Hawkrider

Tires are the number one cause of wobbles...only because it's the most common cause. That does not mean that's the problem. Other causes could be too loose/tight steering head bearings, dented bearing races, balance problems, and my favorite...suspension not tuned correctly. Look for all the former. I can help you with the latter if need be when I get back from vacation in August.

Oh, and unequal compression damping does not apply to our forks since that setting is fixed and non-adjustable.

killer5280

Even if compression damping were adjustable, would it apply? I have seen test rigs with all the damping in one fork leg and the spring only in the other. Since the forks are bolted together in 3 places, I think of them as a single unit and any differences between the two legs gets averaged. I'm not saying it's not a good idea to get them close in settings, but it's certainly not imperative. In fact, I think it would be damn near impossible to get them exactly the same.
I have been chasing a high speed wobble in my Hawk for awhile now. So far, it hasn't been the wheel bearings, steering head bearings or a sticky caliper piston. Damping and ride height settings have been adjusted to no avail. Now I think it's the front tire. At least I hope that's what it is cause I'm getting tired of messing with stuff only to have the problem remain.

smokinjoe73

Superhawks & VFRs are notorious for headshake in a similar way.they are both hyper-sensitive to tires & tire wear. It is made worse by the wimpy head bearings that detent easily. My vote is tire wear but the shake may never be perfect; even a cheap steering damper will be cheap insurance. Change the head bearings; they need it.

hawxter996

hate to say it but frame may be twisted also.
your buddy said it slid into a car correct?

i would look into tires and such 1st but if it persist,get the frame checked.

gboezio

The head bearings seem to be a PITA to torque, I'm about to do it on mine, does anyone know what size is the spanner socket ??
I hope it cures my headshke problem.

As for yours, I'd say the head bearing need a re torque.
Torque it to 16 lb/ft, then go five time lock to lock, then torque again, try one more time for peace of mind and to see it it holds it's torque, if not, the bearings need replacement.

996er

Honestly I feel like it got bad after I put on the new front tire. I took it off after this place extreme machines in NJ mounted and balanced it for a small fortune. I took the wheel off the next day when It didnt feel right and had it balanced again somewhere else. Second time I watched the guy do it at a different shop. Im getting the new rear tire mounted and balanced saturday. Im a big fan of the twisties so two new dunlop qualifiers should help me out in the turns over 100. By the way...the bike had about 21,000K on it. Since I got it 3 months ago Ive put about 5,000K on it. Anyone On here from NJ and wanna ride?

KC-10ENG

Make sure that you check the steering head bearings. While you have the front wheel off just gently move the front end around if it is nothchy at all you need to replace the bearings. AllBalls makes a nice kit that i used when i did my front end swap.

Dennis

mwdejager

My VTR has only done about 6000 miles, 3000 of which I've added in the last 4 months. Never a problem and I've been riding it harder and harder as my confidance improved. This Sunday I just came off a very twisty mountain pass where I really learnt to appreciated th VTR's sharp cornering, and was going a lot faster than usual on the straights. I was often doing upwards of 120 mph and everything was still just sweeeet.
Then I got to a little section of road which was pretty straight, but bumpy so I had to check my speed. At around 85 mph, minding my own business out of the blue a tank slapper - WTF??? After seeing me total the bike in my mind's eye, and stiffening up my arms in a desperate attempt to save it, I managed to get it out of the slapper - only to have it return return a second later. The second slapper was not as bad, but I was scared out of my wits by then.
Is it simply the bumby road or what? After that I maintained a more civilized 75 until the surface improved a tad...

RCVTR

Your forks are bent. The stanchions (upper tubes) are thick walled and soft. They bend easily. Mine were bent when I got my bike. It had 320 miles on it and some minor scratcehs on the fairing. I decided to check the forks and sure enough, they were bent.

The best way to check them is to disassemble and lay the stanchions in V-blocks and measure with a dial indicator as you rotate the tubes. I think the tolerance is .005" TIR (total indicated runout).

I was able to straghten mine with patience and a hydraulic press. I got it well within tolerance. It's tricky because you have to bend it past center and let it spring back, but it works if you take your time (and have access to a shop).

It's much harder to do with something like RC51 forks. They have larger diameter, thin-walled, high yield strength tubes that are much harder to bend and tend to dent where you push on them.

smokinjoe73

I found that changing the steering bearings to tapered rollers, replacing the front wheel bearings, and mostly new tires added hugely to stability. No problems since. Have @ 18k miles but tuff miles; lots of cold weather & bumpy city streets. Oh yeah, I changed to race tech springs & new fork oil. This is all stuff you gotta do anyway, headshake just provokes you to do it NOW.

Tweety

With the stockers that is about par for the course... they don't like to rough of surface at speed... Bent or not... don't push it on rough asphalt... they won't soak it up...

BTW what happened with 996'ers problem? Any solution or clues?

RCVTR

I believe bent fork stanchions are causing misalignment of the front wheel. It's doing the shopping cart wobble.

Tweety

I'd put my money on that to unless the new rear rubber solves the problem... Those are my two best bets...

j shizzy wizzy

I really hate it when someone has a problem, then everyone chimes in like the 'hawk is a death trap unless you do this certain mod. i agree, i dislike the front suspension, but what happened to just riding your stock bike within sane riding limits? now i'm worried about a tank slapper just because i have a stock set-up! i wonder how many bone stock hawks there are out there that have high mileage w/o ever having any serious problems.... bah humbug....

Tweety

The simple fact is that if you are at around 200 lbs the front fork is inadeqvate... Not dangerous... but definetly in the category of "scary as hell" when braking... It goes straight... but it dives, oh man does it dive... Then try it with upgraded calipers... it was really scary... just touch the brakes and keep your tongue at the back of the mouth... blammo, instant compression...

Also fun... having the front compress in a corner until the front started to push, not from lack of grip from the tire, but from the spring going stiff at the end of the movement... just from corner speed combined with my bodyweight... That was a sure winner in the scare me half to death contest...

So yeah... the front is undersprung... But dangerous? Nope... not hardly... again, at sane speeds... and unless you are a heavy weight like me...

But will you benefit from having the correct springs for your weight? YES!... Even if you aren't doing stupid speeds? YES again...!
Do you need to swap out the whole front end like I did? NO!!!! That was just me being lazy and fixing all my gripes with one go...

And with the previous owner crashing it as described above, the odds of a tweaked fork is rather high...

OH! And if you have a bone stock fork, if you haven't put a fresh batch of fork oil in there every two to three years, THEN you might consider being worried... That's not a mod, that's maintanance... Which apparently every one chooses to neglect?!...

j shizzy wizzy

sounds like i need to change my fork oil! thanks for the follow up.
i might look into a front end swap maybe next year. i weight 175, and you are right, the front end feels like a cheap mountain bike the way it compresses at the flick of a brake. kinda makes me nervous in some turns.