Handlebar headshake without hands - Honda CRF1000L Africa Twin Forum
Reply
 
Thread Tools
post #1 of 15 (permalink) Old 12-14-2019, 06:38 PM Thread Starter
Junior Member
 
Join Date: Dec 2019
Posts: 4
Handlebar headshake without hands

I have the following symptom. When decelerating the motorcycle and taking hands off the handlebar, when the speed drops from 70 km/h, the handlebar begins to slap strongly. The problem stops when I grab handlebar again. If take off my hands, the slapping starts again and stops below 40 km/h. I thought it was a problem of balancing the front wheel, but it's ok, tire and spokes are correct. The funny thing is if I take out the top case, where I carry about 5 kg, the problem is almost over, I only get a minimun slap. If I drive with the top case installed, the problem returns, with strongs slaps, so I can think that is an weight distribution issue. I tried increasing the shock preload aboit 5 clicks, but still continues. Front steering stem is thighten ok as factory. Over 80 km/h and below 40 km/h if I take off hands from handlebar, I have no problems.
Any ideas?
Thanks for any suggestion.
Yamaha_Rider is offline  
Sponsored Links
Advertisement
 
post #2 of 15 (permalink) Old 12-14-2019, 07:05 PM
Senior Member
 
Join Date: Sep 2017
Location: Yorkshire, England
Posts: 115
How old/worn is the front tyre ? Mine tend to start 'cupping' at about 5k miles/8k km and start to vibrate thru the bars a little
Dave B is offline  
post #3 of 15 (permalink) Old 12-15-2019, 02:09 AM
Junior Member
 
Join Date: Oct 2019
Location: Pembroke NH
Posts: 5
Adding 5 clicks to rear preload isn't much. Try adding a bunch more. I run the rear preload almost maxed out to get the correct sag with no bags (I weigh 215 lbs). I've also seen tires cause this problem. They looked good, balanced good, wheels tracked good, but had some headshake similar to what you had. Replaced the tires and all was good.

2018 ATAS
2018 MT-10

Last edited by apmech; 12-15-2019 at 02:16 AM.
apmech is offline  
Sponsored Links
Advertisement
 
post #4 of 15 (permalink) Old 12-15-2019, 05:08 AM
Junior Member
 
Join Date: Oct 2017
Location: Near Monterey, California
Posts: 20
Head shake as you described is almost always related to the front tire. I have seen brand new tires do this. Sometimes letting the air out and unseating the tire, then rotate the tire on the rim about 90%, straighten the tube and re-inflate and balance and see what happens. Some tires just do this. I've seen two of the same brand, tire type where one tire will shake and another won't. It is also worth checking your steering head bearings to make sure they are not too loose or may have a damaged bearing race and a rough spot in the bearing.

Dan
bdalameda is offline  
post #5 of 15 (permalink) Old 12-15-2019, 06:29 AM Thread Starter
Junior Member
 
Join Date: Dec 2019
Posts: 4
Thanks for all answers. The front tire is about 6k kms, Pirelli Scorpion AT. I will try with a new tire, but is still strange that with more load on tail, the symptom increases.
Yamaha_Rider is offline  
post #6 of 15 (permalink) Old 12-15-2019, 06:56 AM
Member
 
Amphib's Avatar
 
Join Date: Jul 2019
Location: Asheville NC
Posts: 43
Quote:
Originally Posted by Yamaha_Rider View Post
Thanks for all answers. The front tire is about 6k kms, Pirelli Scorpion AT. I will try with a new tire, but is still strange that with more load on tail, the symptom increases.

I had an issue like that, same as you describe, adding a bunch of preload in the rear solved it. It occurred while on my first camping trip on the bike. It was the first time I really loaded it down. I even took the front wheel into a shop, got it rebalanced, I checked all the spokes for tightness... It got a little better. Steering head bearings were fine. I was not a happy camper. While riding I started trying to shift my weight around the bike to see if anything helped and I noticed it went away when I was putting all of my weight on the tank and bars (bringing my weight forward). So I cranked up the preload on the rear shock... I maxed it out given my weight and load, and problem was solved. Hope this helps. It was disconcerting to say the least.
Amphib is online now  
post #7 of 15 (permalink) Old 12-15-2019, 11:02 AM
Senior Member
 
Join Date: Feb 2017
Location: Colorado, USA
Posts: 163
If you're tires are good, wheels are good/well maintained, your steering head is properly adjusted, then it's mostly likely suspension.... Years of roadracing has taught me when you get head shake it's usually because you aren't running enough preload in the rear. What you describe is the case. You have added weight to the rear therefore lightened up the front. You need to put weight back on the front by adding preload to the rear to return the bike to the proper geometry.

Just adding preload randomly without measuring the actual sag is just a guessing game. Did you have the bike preload set to your weight (front and back) or whatever your primary riding weight is? Meaning do you always ride with a passenger, a top case? Then you need to measure preload for that. Then add whatever you want to the bike and re-measure preload. Make note of how many more clicks it takes to get it correct. Now you can switch between unladen and laden...

First thing I do with EVERY one of my bikes before I start farkling it, is get the suspension correct even if that means getting it re-sprung, re-revalved or whatever. For me on my ATAS, to get the suspension set correctly I went with an Ohlin's rear and spring and valving in the front.... Always money well spent.

2019 Africa Twin Adventure Sports
AdvArt is offline  
post #8 of 15 (permalink) Old 12-15-2019, 03:25 PM
Member
 
Red Maverick's Avatar
 
Join Date: Jul 2019
Location: South East England
Posts: 73
A bike is most stable under a constant throttle


Closing it as slow speeds and a big front wheel takes momentum of of the geometry = head shake

Enjoy an Adventure
Red Maverick is online now  
post #9 of 15 (permalink) Old 12-15-2019, 07:07 PM Thread Starter
Junior Member
 
Join Date: Dec 2019
Posts: 4
The rare thing is than in my previous bikes (KTM 990 and KTM 950, Yamaha XT600) I never had those problems, I had played with suspension settings only for off road adaptability, never measured the sag and never concern about my weight or weight of rear bags or panniers. The only symptom won that bikes was feeling the steering more "light", but never slap or headshake.
For this AT I have changed the rear spring for an Hyperpro progressive. The rear shock now feel more "confortable", really good for off road bumps, but the headshake continuesin the same way as original spring, even now with the preload on max setting. I am not a heavy guy (70 kgs) so I dont think that I need a "harder" spring.
Yamaha_Rider is offline  
post #10 of 15 (permalink) Old 12-16-2019, 08:50 AM
Senior Member
 
roy826's Avatar
 
Join Date: Aug 2018
Location: Brandon MS
Posts: 100
OEM Springs are just way to soft on this bike causing rear to sag. This will induce the head shake you are seeing.

My bike is sprung for me with Ohlins front and rear and it does not do this empty with me loaded or anytime. It did do it on stock suspension.

2017 CRF1000 DCT candy apple red
roy826 is online now  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Honda CRF1000L Africa Twin Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in













Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome