FinalVelocity
Expert Class
Posts: 150
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posted May 31, 2002 11:55 AM
Headshake and Tires.
I've decided to go with new tires because the 45-60 head shake I've been having has'nt gone yet and I'm thinking my front Pilot Sports may be the problem. My rear Michelin Pilot is still in a damn good shape though but I'd still like to eliminate the Pilots out of the equation. This is because if I just change my front Pilot and this nasty head shake remains, there could be a possibility that the rear might be contributing to the problem right? Then I would have to buy 2 more tires, and wasting my Front Pilot purchase. Maybe the 12R just does'nt take too well to Michelin Pilots....whaddya think?
I've had pretty much everything on the bike checked out - stem bearings torqued, wheels balanced and aligned etc and the head shake still has'nt gone. I'd like to change the tires and eliminate that too. Bike has never been down (touchwood).
The bike also tends to drift at freeway and higher speeds. I know for sure my steering is not neutral.
So what's a good tire choice guys? Should I go back to the Dunlops D207s? How're the BT010s?
Suggestions please!
  
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frEEk
Administrator
ummm... yeah
Posts: 9660
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posted May 31, 2002 12:28 PM
get ur forks checked. this has helped several members with the same problem, most noticeably fish. my bike seemed a little more stable after the 10,000km service too (which includes fork maintenance).
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FinalVelocity
Expert Class
Posts: 150
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posted May 31, 2002 12:51 PM
What do I have them checked for, Freek? Change the oil or what?
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GG
Expert Class
Posts: 187
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posted May 31, 2002 01:36 PM
How many miles on your Michelins?
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frEEk
Administrator
ummm... yeah
Posts: 9660
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posted May 31, 2002 02:27 PM
i'm not entirely sure what they do. it's whatever is included in the 10,000km service. fish could give u a better idea since he was the one who had the best results.
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FinalVelocity
Expert Class
Posts: 150
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posted May 31, 2002 08:49 PM
GG - I've got about 3000 miles. They're in good shape - still have ample tread left. I'd hate to waste a perfectly good set of tires but I will if it means this nasty shake is gone and the bike handles neutrally.
Fish - can you comment on what fork work you did to eliminate this shake?
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FinalVelocity
Expert Class
Posts: 150
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posted May 31, 2002 08:56 PM
Another school of thought is bad front wheel bearings. I think I'm going to be spending some serious money trying to hunt this shake down.
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EastBayDave
Needs a job
Posts: 2245
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posted June 01, 2002 05:06 AM
That's pretty weird. Something somewhere must be in mis-adjustment or mis-alignment if the tires are not worn out. I'd double check the suspension settings on both the front & rear. Back them all the way down counting as you go; & make sure compression/rebound on the forks is identical to each other. Check the rear too for grins...
Also you say the alignment is ok, how did you check it? Marks on the swingarm (notoriously wrong), or did you use the old string method. Has the bike ever been down/dropped?
Then there's always the make it better method like I did; Muzzy Dampener. Expensive yes, but make a stable bike even more stable. The most stable bike I've ever had... 
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Enjoy the ride!
02' ZRX1200
00' ZX12R sold
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12RPilot
Pro
Posts: 1094
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posted June 01, 2002 06:06 AM
Computrac?
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If you aren't an AMA member, you're part of the problem.
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http://www.bikepics.com/members/12rpilot/04zx10r/
 
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DaveInDaytona
Pro
Posts: 1696
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posted June 01, 2002 07:03 AM
EastBayDave hit on the front shake problem I had on my new bike. When the front got light it was a little scary so I checked it and the forks weren't adjusted the same. Got out a wrench and screwdriver and made sure everything was the same, shake gone. One of a few problems that could cause it but that was the ticket for me.
IMHO - The damper is a good idea to make the stability better, but fix the problem first then add it. I'm waiting on mine right now.
Dave
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DaytonaSportbikes Forum
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FinalVelocity
Expert Class
Posts: 150
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posted June 01, 2002 03:21 PM
Front tire look OK but well I'm starting by changing the front tire. If that does'nt fix the problem I'm going to check on the suspension.
Rear alignment was not checked with the marks but with a nifty tool that measures the distnce between the center of the frame and the axle. Spot on. Stem bearings have been torqued to spec. Front wheel is also balanced.
What else could I have left out.....
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EastBayDave
Needs a job
Posts: 2245
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posted June 01, 2002 04:16 PM
 Edited By: EastBayDave on 3 Jun 2002 06:27
Wait a minute...before you go & change the tire, grab a screwdriver, a pen & paper, & lets check your suspension settings FIRST & make sure they are not unequally adjusted. You may not have to change a tire...
Mark your notes: Suspension Settings (or whatever.)
Right Fork Compression
Right Fork Rebound
Right Fork Spring
Left Fork Compression
Left Fork Rebound
Left Fork Spring
Shock Compression
Shock Rebound
Spring turns IN
Glance at the springs (w/glasses if needed) & jot down where each preload line is. 1 line, 2 lines, 5 lines, etc.
WRITE IT DOWN. If the two are uneven, grab a socket (15mm? I forget.) & make sure both preload adjusters are equal to each other (same # of lines out.)
==============================================================
Grab a big flatblade screwdriver & drive the rebound adjuster in counting each "click" as you go -slowly. Stop when it bottoms (don't force it.) WRITE # (of clicks you felt going down) IT DOWN NOW!
Now back it back out counting clicks again until your back where you started. If you get lost, return to the "seated" fully position & start over. Repeat several times until you get the "feel" of it & are positive where it resides (5 clicks, 10 clicks, etc.) WRITE IT DOWN.
Now go to the opposite fork, repeat above procedure exactly the same. When you're done, you should know where both rebound adjusters are by the # of clicks out.
==============================================================
Repeat above procedure again with the compression adjuster. Drive it in all the way, feeling for clicks & counting. Once seated, WRITE IT DOWN; then back it out to where you started. If you loose count, go back in fully & start counting again.
Switch to the other fork & do the same procedure again. Going in & counting, seating, writing it down, going back out. Again making sure both forks are SET identically. Bingo, your forks are NOW set equally, & you now have a written record to draw from.
==============================================================
Do the same procedure on the rear shock. Click in the two adjuster's one at a time, noting # of clicks in to seated position. Count it back out; do it again with the other adjuster. Write it down. Bingo, you have the shock settings in your notes.
==============================================================
Now that you know where everything is (& have corrected any un-equal settings), you can troubleshoot the suspension settings to see if it's too soft, too hard, & what is on which setting. Let's worry about the rear spring setting next time...
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Now, you are ready to make adjustments @ you favorite twisties.
Next time your up there, bring your notes, a screwdriver, & bingo: Make adjustments a click on each side at a time, (adjusting equally), noting the change from where it was.
Now ride da bike! Feel the difference; stop, make a change, note it, repeat, repeat, etc. Now you have set your suspension yourself, & the bike is probably working better after doing this 1/2 dozen times...
Now how is it working??? Try this & let's go from there...
Questions? e-mail: dwright2@ix.netcom.com w/your phone number...
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Enjoy the ride!
02' ZRX1200
00' ZX12R sold
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FinalVelocity
Expert Class
Posts: 150
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posted June 01, 2002 07:22 PM
OK Thanks Dave. I will try this out and post back shortly.
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted June 02, 2002 06:43 AM
moderate head shake
I found on my 12 that measuring off the back end of the swingarm to the axle block is within .020" of the rear tracking the front true.
This is about 1/2 a mark off on the side of the swingarm.
But a tracking problem has never caused a head shake problem on any of my bikes I've owned. It will make the bike better turning in one direction than the other.
90% of the time a head shake going straight at a moderate speed is caused by front tire cupping. And cupping is caused by hard braking.
In every case with any of my bikes, when the bike has a mild head shake at about 40 mph it went away with a new tire up front.
Tread depth on the front isnt a good indicator of how good the tire is or how many miles are left on it.
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FinalVelocity
Expert Class
Posts: 150
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posted June 02, 2002 04:06 PM
Y2K - I do think this might be the real problem - though I still need to dial the suspension in to suit my weight (230) and riding style (not too hard).
Dave - I inspected the front Michelin in detail today - though the tread is more than 2-3 mm, there is *slight* cupping on the treads now that I notice it. I don't know if there is enough cupping to cause this head shake though - let's see what happens once I dial the suspension in correctly.
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EastBayDave
Needs a job
Posts: 2245
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posted June 03, 2002 05:31 AM
quote:
Y2K - I do think this might be the real problem - though I still need to dial the suspension in to suit my weight (230) and riding style (not too hard).
Dave - I inspected the front Michelin in detail today - though the tread is more than 2-3 mm, there is *slight* cupping on the treads now that I notice it. I don't know if there is enough cupping to cause this head shake though - let's see what happens once I dial the suspension in correctly.
Yeah, it may be the tire; but make sure its not the suspension settings first (the free way  .) Once your sure the settings are equal, then you can go from there...
Keep us updated...
Dave
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Enjoy the ride!
02' ZRX1200
00' ZX12R sold
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FinalVelocity
Expert Class
Posts: 150
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posted June 04, 2002 06:24 AM
I will. Gonna be raining till Friday here in Detroit. I plan to get to it this weekend. Man I'll be one relieved man when this damned head shake is gone.
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GreenMamba
Parking Attendant
Posts: 26
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posted June 04, 2002 07:12 AM
Michelin
Also, make sure the front tire is properly balanced.
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Zhooligan
Moderator
Post Whore Extraordinaire!
Posts: 3829
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posted June 04, 2002 07:57 PM
You don't by chance have a friend or someone you know nearby with a 12 do you? If so a quick swap of front tire and wheel might give you a clue.
The issues I have seen cause head shake are:
fork height is not the same for both forks.
Forks and tripple clamps are twisted (not properly aligned)
Steering head bearings loose and or worn out.
tire out of balance
Cupped tire and and or a broken ply or chord
forks pushed up too high in the tripple clamps
Damaged rim
Good luck!
____________
To those who do not count their life in years, but in how life
has touched them in the past and how much it can hold in the
future; -- Youth is forever.
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beansbaxter
Needs a life
Posts: 5911
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posted June 05, 2002 04:34 AM
I'm not trying to sound stupid, but what is a "head shake" problem?
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fish_antlers
Administrator
The Truth is Out There
Posts: 21894
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posted June 05, 2002 05:20 AM
sorry for the delay... I am in work hell.... the fork were removed, dismateled and reassembled by the dealer, fork fluid replaced... I can get an exact procedure from Burnaby Kawi, but it did solve the prob 100%.
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EastBayDave
Needs a job
Posts: 2245
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posted June 05, 2002 05:34 AM
quote:
I'm not trying to sound stupid, but what is a "head shake" problem?
Some call it "speed wobbles"....
When the bars "wobble" back & forth in your hands; typically under acceleration. Wobbles can lead to "tank slappers" (bars going back & forth between the fork stops) which could cause a nasty bail @ speed...
To be avoided at all costs...
____________
Enjoy the ride!
02' ZRX1200
00' ZX12R sold
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Hells Dark Lord
Needs a life
living life, and loving it.
Posts: 7981
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posted June 09, 2002 05:51 PM
tank Slappers
I saw a guy go into a ank slapper in the middle of 130mph right hand sweeper......threw him into to a highside pitch, he flew almost 75 feet. Fortunately for him he was n the track and had all of his gear on...it threw him over into the grass where he slid for prolly close to 100 more feet before he started to tumble the last few...he was lucky. Head shake scares me to death, my 01 ZX6r is rockl solid at WFO. My ZX12R has a hake under hard acceleration at any speed, makes me use throttle control. Guess I should use that on this bike anyway eh....lol
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When in doubt, lean farther and go faster....
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TedG
Moderator
Posts: 8222
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posted June 09, 2002 08:22 PM
I haven't had time to read the entire set of posts, but it looks like no one mentioned steering head bearings. Usually aluminum frames have a tendency to beat the races into the frame. A loose steering head allows all sorts of wierd things to happen to the frame. Also the swing arm loosens up on the 12 and also does funny things. An out of balance tire can cause a headshake on a incorrectly adjusted head. Be aware that an over tightened head will cause a shake also, it goes one direction and instead of relaxing and straightening out it binds and then over corrects.. Bad Bad Bad. The tire brand is not the problem, I run them and I can let go of the handlebars at any speed and the thing is steady as a rock. The tires could be the problem but only if they are worn funny. Even then properly inflated and properly adjusted bikes won't usually shake.
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Ted
2000 Green ZX12 sold
The fast color!!
Green 2005 ZX10R
2009 Concours Black ABS
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fish_antlers
Administrator
The Truth is Out There
Posts: 21894
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posted June 26, 2002 09:27 AM
my headshake has reappeared... I'm not sure what to do.... dealer is now replacing steering head bearings.... odd as they think I am nuts, but I have had this prob from day one of owning the 12... I think it sux... I wish someone could nail down the prob as it seems to affect a few members out there...
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