Choppiness at high speeds (above 115mph). Help?

O

OB_Mabusa

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My bike has been "choppy" since day one at high speeds. I changed front and rear rubber early and had them balanced thinking it had something to do with the tires. No change with the new rubber.
I was lubing the chain on the rear stand yesterday. Staring directly from behind at the lowest point on the sprocket I noticed the chain "dancing up and down about an 1/8 inch and side to side about a 1/16th. XXlr8 said I should check the sprocket because it might be a little out of round. I happened to have a used one with 1500 miles on it so I decided to put it on today. After installing I started the bike in gear and the same "dancing" occured.

What I found is hard to describe without pictures but here goes..........The thing that the rear sprocket bolts to looks as if it is a casted piece. It is supposed to have a smooth shiny silver finish all the way around it that can be seen behind the sprocket next to the wheel. My piece has two setions that are not smooth or shiny and not silver. The 1 inch sections are rough like sandpaper and have cracks in them that go all the way through it's thickness. It's as if they didn't put enough metal in the casting mold or something. I am almost sure this manufacturing problem has been causing the "choppiness" at high speeds. Two of the bolts bolt into where these rough cracked areas are.

I think you guys should check the quality of this piece on your bikes and see if you got a bad one also. Am I the only one?
 
Mabusa, the hub on my 99 has the same poor quality casting problems (not smooth) and has numerous hair line cracks neither of which seems to effect the performance. My machine is smooth at all speeds. Other than being lowered two inches front and back it is completly stock. Sorry i mcannot help further.
 
I have checked the suspension settings but when the bike is up on its rear stand and I can watch the rear sprocket "dancing" around I doubt if it has anything to do with the suspension settings.

Anyone else have really poor casting and many cracks on the hub where the rear sprocket bolts on?

Thanks guys for sharing your tales with me!

[This message has been edited by Mabusa (edited 10 August 2000).]
 
RECALL, RECALL,RECALL!!!try checking tire pressure!This will cause wobble just like you mentioned, also i wasn't sure,and i hope your not this stupid, you did have all that fix-o-flat crap removed didn't you?
 
I gues our problems aren't that similar after all. My bike has been this way since I got it. Breaking it in I didn't even see speeds over 115mph so it wasn't a factor. The more I get used to the bike and feel like I'm it's master (instead of the other way around) the more I want to go faster and faster.
Now is when the choppines is becoming a big issue. After about 5000 miles.
 
All hayabusa hubs have the casting flaws. If you take it to a dealer they will replace it underwarranty but any one you get will be the same.

By the way, my bike had been vibrating real bad at 115mph and got worse the faster you went. Took front tire off and rebalanced it, now I how a wobble in the bars at 45mph. Rebalanced again, still wobbles. Did a run out on wheel and both rotors, all perfect. Replaced front tire and balanced, still wobbles. Bike is in the dealer right now but I doubt they will fix it so if you find your vibration keep us posted.
 
Dangermouse, if youre asking me, I just recently installed the rear wheel and hub. The rubber blocks for the cush drive have plugs that stick through holes in the wheel. The plugs holds the blocks in the wheel and the outer hub has dividers that fit in between the slots on the rubber blocks. I don't think I could have put it in wrong, it'll only go one way. My rear wheel and tire combo was .25oz off on the final balance. The guy and the shop said that was fine and you wouldnt feel it. Do you guys think that may be it?? Some shops don't even balance tires at all, why would it be that picky over 1/4 oz?
 
Zxalan your bike seems to have the same symptoms mine does. How long has your bike been in the shop? Any info on things you've/they've tried that I can print out and give to my mechanic when I finally bring mine in?

I have been up to 155 mph once but it was to scary for me. AFTER 120MPH IT STARTS CHOPPING, SHAKING AND VIBRATING.
It really isn't such a big deal because how often do I exceed 120 for extended periods? Not very often. I like the rush from 0-120!

Sometimes I wanna go 190, dammit!

Anyone else?
 
Have you removed and greased your steering head bearings??

I think it was JC who mentioned they came dry from the factory (this was confirmed by DaveP who did his before last week he reckoned they were drier than a Nuns C**T!!)

Nuts ;)
 
MABUSA, heres the whole story. My bike had 3000 miles when I decided to chrome my wheels. While my wheels were off I decided to go ahead and get new tires.

1. Installed chrome wheels and new BT56j's.
No problems, 30 track passes, smooth as silk.

2. July 4th, front valve stem blows out on the freeway, I add a full can of Fix-a-Flat to get me to the shop.

3. The shop simply pulled the tire away from the bead and installed a new stem without ever cleaning or rebalancing the wheel. I rode the bike, seemed fine but I didn't ride it hard for about 200 miles.
Started to ride it hard and noticed a BAD vibration at 115 mph and got worse that faster I went. But at slow speeds it was smooth.

4. Took bike to the shop, they removed,cleaned and rebalanced the front tire. On the way home I noticed a wobble in the bars from 45-65 mph, especially if I took my hands off of the bars, you could see them wobble. The the 115mph vibration didnt seem to be as bad.

5. Took bike back to the shop, checked the front wheel run out and rotor run outs. ALL were fine. Inspected the tire and the seal of the bead, both were fine. Tire only had 700 miles. Rebalanced again, same problem.

6. Took bike in and got my original 56j(3000 miles but still good)mounted and balanced. Needed the exact same amount of weight as the other tire in exactly the same spot on the wheel. Rode it, still wobbles!!! Not as bad but still feel at 45-65mph, especially when you take hands off of the bars. I am pissed.

7. Took it to a suzuki dealer yesterday, I will call them this afternoon, might be done tomorrow. Thats"IF THEY CAN FIX IT" I have checked everything I know to check so either both tires all of the sudden failed or the Steering neck got screwed up. I don't do BIG wheelies or stoppies and the bike only has 4000 miles.

8. I am open for ANY SUGGESTIONS!!
 
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