I just bought a 90 cbr 1000 with 2900 miles on it. Its red, white and blue. The previous owner said he droped it going around a corner doing about 5mph. He replaced all the plastic years ago right after the spill. The bike had the original tires on it. There is road rash about 5 inches long on the lip of the front wheel. It looked like he road on a flat tire. I just had new pilot powers installed and balanced and took her out for a spin. Im getting shaking which seems like its comming from the front end as soon as hit about 90mph and above. The shaking gets a little worst as you go faster. At about 120mph I start getting concerned about loosing control of the bike. It seems to be bouncing up and down compared to wobbeling side to side. I took it back to have the front wheel balanced again and to see if the wheel was bent or if the bearings had issues. The tire installer at the shop said it was a little off balancing but should be ok now. Its still doing the same thing. It was suggested in another post to check the steering head bearing. Also to check the swing arm bushings and rear wheel alignment.

My mechanic isnt back to work until Tuesday and Im curious if any of you have had the same issues. I really think I have a bent wheel. I dont know if he hit a curb or it was caused by riding on a flat or both. I will have my mechanic ride the bike Tuesday, but I dont know if he is going to want to take the bike into those speeds. Do you guys thinks the wheel still isnt balanced properly? The installer says the wheel isnt bent and the bearings are fine. I just bought a 87 front wheel on e-bay for 60.00 just incase my wheel is bent. It includes all the insides,( ie. axle, bearing etc. and the drilled rotors in mint condition). Is this a straight swap for my 90 front wheel? Let me know what you all think.......... I would really appreciate your input!!!!!! And by the way............. Awesome forum!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Thanks a million!!!!!!!!!!!!!!!!!!!!!!! Jonas Dixon

 

I think the -87 rim is a bit narrower and can't take the 120/70/17 tyre which you probably are using now. From your description it indicates there is a major wheel unbalance. It could very well be the rear tyre, if the front is checked OK. Imperfections in rear balance will transfer directly to the front and could cause the symptoms you describe.

 

Sounds like the rim might be out-of-round. The way the installer is balancing the tire might be right but wrong. I've looked at parts catalogs and they sell motorcycle tire balancers. Most only balance out weight from left-of-center to right-of-center. But being a shop they might have a balance machine that operates like a car tire balancer. There aretypes of balancing.... I can't remember onetype but the other is static balance. One checks balance from side to side and the one I can't remember checks for balance from top to bottom. I've asked many questions about wheel swapping on the forum also. The rim you bought for an '87 , as far as I know won't be a direct bolt-in swap. After the '88 model honda redesigned the cbr 1000f and all the '90 and newer parts are all interchangebale easily.

 

Thanks!!! That makes sence. Not sure if ther is a difference in wheel size, I think the only difference id the speedo set up. I might need some speedo parts of the 87. Thanks for your advice, I hope the rear is out of alignment.

 

Thanks Chuck Norris! If the 87 wont work on my 90 I will sell to someone here who has an 87. Im in the wheel 95.00 which included shipping. I may not need the wheel at all; depends on the problem Im having suppose. Thanks for your help guys!!! All info appreciated!!!!!!!!!

 

To check the front wheel, have someone sit on the bike when it is on the center stand so that the front wheel is off the ground. You can stack wood to the height is the wheel and put a nail in the wood so that it is at the level of the rim where it meets the tire. Spin the wheel and look for run out. If it is bent you will know right away.

How is the fork oil? Uneven levels or mismatched oil can also cause some shaking. Are your fork seals good? If some oil leaked out and the level is down you will not get the dampening you need and the front will bounce. It would also get worse with speed.

 

hey bro,
The main cause for that sort of thing would definitely be the steering head bearings. However, there are a few more things that could lead to that feeling at high speeds.

First, check your plastics. If there is a lose part on the front, that might not be noticeable if you give it a little tug, at high speeds, it acts like a parachute and will drastically affect the aerodynamics of the bike.

Next, Check your forks. Make sure you dont have any build up grimey crap on the tubes. If they are clean, i would recommend checking to make sure there is the correct amount of oil in both. IF that is still ok. Check out the springs. If it went down and he didnt check them. They could A. be old in need of replacing(one might be worse than the other, so every time you compress it, one side gets compressed more than the other..or B. there is always a chance that something broke or came undone.

ALSO, are you running the forks at the stock height with the Triple tree, or did he try to lower the front by lifting the fork tubes up and dropping the triple tree cover further down the tube? If this is the case, it will DEFINITELY make the front end unstable at high speeds.

I would also take a good look at the rotors and calipers. If there is anything off, it will grab and be most noticeable at high speeds.

On that old of a bike, i could definitely see the rotors being warped.
There are a few more things, but between what others have said, and this. You should be able to get it worked out.

 

Thanks for all your help guys!!! Im sure I will find out tomorrow whats up. I have a great list of items to check out. I just found out the wheel I bought on E-Bay was previously sold and accidentially re-listed; or so they say...... So if anyone knows of where I can get a 90 wheel let me know in case I need one. I will post on Tuesday and let everyone know what the problem is. Thanks again for all your advise, Im sure I will have the problem solved; especially with all of your input. Jonas Dixon

 

You guys wont believe this. The first shop I took it to just put the new tires on and never balanced them. Even after taking it back to have them check the balancing and tire pressure they took my bike to the back and did nothing. I snuck around back to see what the hell was going on with my bike and found it just sitting in a corner. They flat out lied to me and siad they checked everything out and everything was perfect........ They said the tires were perfectly balanced and the tire pressure was 38 in the rear and 36 in the front; when in actuallity they did nothing to my bike at all.
So yesterday I took it to my regular mechanic who was out of town for the last week or so. Turns out there was only 30 lbs in the front tire and 33 in the rear. The wheels were so out of balance, you couldnt have balanced these wheels any worst. My mechanic said the person who did this to me just stuck the weights anywhere. Anyway I got a hold of the owners of the dealership and the *** hole is fired!!!! They gave me $200.00 store credit. Its nice to have some justice every now and then. I thank all of you for your help!!!!!! I just wouldnt believe in a million years someone would intentionally do this to such a nice person as myself; I had even tiped the *** wipe the day he initially did ( didnt do) the work. Thanks again for all your time helping me with this problem. Needless to say I love this bike!!!!!!!! Now I can hit those speeds this bike was intended to reach..
You guys are the best!!!!! Jonas Dixon.........

 

You should be checking your own tire pressures, I do mine cold. get yourself a good gauge
36/38 doesn’t sound right
look on the forum for the ‘CBR1000F Servicing Manual’ download