GSX1400 Owners .org

Technically Speaking => General Technical discussion => Topic started by: VladTepes on Tuesday, 09 February 2021, 08:18 AM

Title: head shake - this is new...
Post by: VladTepes on Tuesday, 09 February 2021, 08:18 AM
Well it's either new or I've only just noticed it.

When riding at say 30kph + if I let go of the bars the head starts shaking. It's disconcerting and I think if I left it for long enough it'd develop into a decent tank slapper - so obviously I don't let that happen. 

Tyres
Rear - worn in the middle but plenty left on the sides. It's not a square profile or anything extreme like that yet. But pick the commuter. 
Front - somewhat worn esp on RHS of centre (as appears typical)

Any idea where to start at trying to diagnose the cause here?
Title: Re: head shake - this is new...
Post by: Horse on Tuesday, 09 February 2021, 08:36 AM
I would start with the head stem bearings , barring tyre issues it will be something loose in the frame/ suspension ie axles , swingarm pivot but every time I have experienced this it has been the head stem bearing play . If all of that is not an issue the tyre could be suspect but it has not been my experience
Title: Re: head shake - this is new...
Post by: gsxbarmy on Tuesday, 09 February 2021, 08:47 AM
First try the same trip - but without your topbox (if you have one on) as this can cause a headshake under certain conditions (as the top box sits quite a way back off the rear tear, as opposed to more over the rear tyre).

If it stops doing it - then the topbox is the cause and is a known issue - no way around it.

If it carries on doing it - check rear wheel alignment and tyre pressures. Also (and this may sound strange) check your chain adjustment.
Title: Re: head shake - this is new...
Post by: VladTepes on Tuesday, 09 February 2021, 09:03 AM
@horse - any easy way to to check the head stem bearings?

@gsxbarmy Hmm I did change the topbox recently to a slightly larger one.
I'd have never thought of that - will give it a go.

As for chain adjustment - it's gone from well adjusted to pretty loose in just 3 weeks, thus my other thread re chains and sprockets.

Wheel alignment - I'm hopeless at that, I must admit but it seems pretty damn close.

Tyres - tyre pressures seem to be OK / what I usually run.
Title: Re: head shake - this is new...
Post by: Hooli on Tuesday, 09 February 2021, 01:06 PM
My topbox always caused exactly that until I had to bolt the box on, now it doesn't move the steering doesn't shake.

I'd go for tyre wear from how you describe the front one.

If you hold the front brake on and rock the bike back n forth, any clunk or movement in the stem is too much. I tend to lean the bike slightly on my hip and check with my left hand's fingers just touching the stem and top of the frame in front of the tank. You'll notice smaller amounts of play that way.
Title: Re: head shake - this is new...
Post by: Kiwifruit on Tuesday, 09 February 2021, 03:14 PM
Tyres for me, l'd be checking for an abnormality. If you spin the wheels by hand you may feel a small bump. Sounds like the tyres might be nearly done.
Title: Re: head shake - this is new...
Post by: Grumpy old man on Tuesday, 09 February 2021, 04:36 PM
I would bet on it being the front tyre 

Michelins did this on my Tiger Sport when 1/2 worn Metzeler and Pirelli no problems even when almost thread bare
MY ZX 14 did that on new Mich road 4's

I always change a set even if 1 still has good tread
Title: Re: head shake - this is new...
Post by: KiwiCol on Tuesday, 09 February 2021, 05:46 PM
You wanted Road 5's anyway Mike . .  now's your chance.
Title: Re: head shake - this is new...
Post by: grog on Tuesday, 09 February 2021, 06:13 PM
Agree with tyres, they are worn so need replacing even if no shake. Head bearing adjust, also something to do. If you adjust you then know correct. Thats my thoughts.
Title: Re: head shake - this is new...
Post by: Horse on Tuesday, 09 February 2021, 11:53 PM
Quote from: VladTepes on Tuesday, 09 February  2021, 09:03 AM
@horse - any easy way to to check the head stem bearings?

@gsxbarmy Hmm I did change the topbox recently to a slightly larger one.
I'd have never thought of that - will give it a go.

As for chain adjustment - it's gone from well adjusted to pretty loose in just 3 weeks, thus my other thread re chains and sprockets.

Wheel alignment - I'm hopeless at that, I must admit but it seems pretty damn close.

Tyres - tyre pressures seem to be OK / what I usually run.

As has been said one way is to rock on the front brake on feel if there is any play or get the front wheel in the air and grab both fork lowers and rock back and forward also checks free play but as per the manual there should be from memory 300-400 grams of preload on the head stem at the handgrip With the wheel off the ground.
Title: Re: head shake - this is new...
Post by: Hooli on Wednesday, 10 February 2021, 12:09 AM
Quote from: horse on Tuesday, 09 February  2021, 11:53 PMget the front wheel in the air and grab both fork lowers and rock back and forward

That is also a good way to spot play in the fork bushes, as you can feel/hear where the movement is easier than from above.
Title: Re: head shake - this is new...
Post by: DP1400 on Wednesday, 10 February 2021, 07:37 AM
I`d stay with the front end and check the easy stuff first, ie. head/wheel bearings, but its worth considering whether you have a brake defect developing - a very slightly warped disc binding on the pads maybe? I had this problem on a `Blade once, the slower I rode amplified the feedback through the bars. Easiest resolution was to keep the front wheel airborne..... :facepalm: Sorry, couldn`t resist the last bit!! ;)
Title: Re: head shake - this is new...
Post by: VladTepes on Wednesday, 10 February 2021, 02:42 PM
Brake discs replaced not too long ago. Doubt its that.

Quote from: KiwiCol on Tuesday, 09 February  2021, 05:46 PM
You wanted Road 5's anyway Mike . .  now's your chance.

True :) But I've gone off the idea of Road5's (only because I've always had Michies and want to try something different) so the Bridgestones which come recommended on here  a lot are a good chance.


Title: Re: head shake - this is new...
Post by: mlivkovich on Wednesday, 10 February 2021, 03:44 PM
Maybe tire cupping makes front end shake at low speed :whatever:
Title: Re: head shake - this is new...
Post by: Eric GSX1400K3 on Wednesday, 10 February 2021, 04:13 PM
Vlad,

Have you checked that your bar ends are still fitted tight? I lost one somewhere , did not notice it until i took my hands off the bars and the bike started to want to go left.  I ordered new ones that night, heaviest i could find, as i run aftermarket Eaton tapered bars which are lower and wider.  Makes the steering nice and light.  Worth a check i think.
Title: Re: head shake - this is new...
Post by: VladTepes on Wednesday, 10 February 2021, 05:15 PM
@Eric GSX1400K3  I haven't got any bar ends mate as I have Renthal bars. I've been on the look out for good heavy bar end weights (ie not aluminium bling) - akin to the originals but to suit the Renthals.
Title: Re: head shake - this is new...
Post by: Eric GSX1400K3 on Wednesday, 10 February 2021, 05:21 PM
Quote from: VladTepes on Wednesday, 10 February  2021, 05:15 PM
@Eric GSX1400K3  I haven't got any bar ends mate as I have Renthal bars. I've been on the look out for good heavy bar end weights (ie not aluminium bling) - akin to the originals but to suit the Renthals.

Check out Rated R parts on ebay. Steve is perth based but posts all over. Thats where i got mine from
Title: Re: head shake - this is new...
Post by: grog on Wednesday, 10 February 2021, 06:24 PM
Vlad, your tyres are worn out you said. So obvious what your first thing to do is. As far as Bridgestone, not a tyre id use. Just me. Have seen front on two mates bikes, just rooted after very low ks. I like my Angels, never a prob. 2nd set. Next time might give Metz Roadtec a go. Good reviews and say more planted front end than others. Can of worms for sure.
Title: Re: head shake - this is new...
Post by: Notty on Wednesday, 10 February 2021, 10:19 PM
Quote from: VladTepes on Wednesday, 10 February  2021, 05:15 PM
@Eric GSX1400K3  I haven't got any bar ends mate as I have Renthal bars. I've been on the look out for good heavy bar end weights (ie not aluminium bling) - akin to the originals but to suit the Renthals.
You can use originals bar ends or heavy similar  on Renthal using a rawlpug expanding bolt-check youTube  :)
Title: Re: head shake - this is new...
Post by: Hooli on Wednesday, 10 February 2021, 10:54 PM
Any after market bar end with an 'expanding plug' type fitment will fit. I know an ex got some heavy ones off ebay that just had a bolt that crushed a rubber bung so it jammed in the bars & they fitted her renthals.
Title: Re: head shake - this is new...
Post by: Snapey on Thursday, 11 February 2021, 01:58 AM
Quote from: VladTepes on Wednesday, 10 February  2021, 05:15 PM
@Eric GSX1400K3  I haven't got any bar ends mate as I have Renthal bars. I've been on the look out for good heavy bar end weights (ie not aluminium bling) - akin to the originals but to suit the Renthals.

I made a couple for my Pro Tapers in stainless. The groove is for the bark busters and they're held in with an M4 grub screw. A very rough sketch might explain.
Title: Re: head shake - this is new...
Post by: VladTepes on Thursday, 11 February 2021, 08:37 AM
Quote from: grog on Wednesday, 10 February  2021, 06:24 PM
Vlad, your tyres are worn out you said. So obvious what your first thing to do is. As far as Bridgestone, not a tyre id use. Just me. Have seen front on two mates bikes, just rooted after very low ks. I like my Angels, never a prob. 2nd set. Next time might give Metz Roadtec a go. Good reviews and say more planted front end than others. Can of worms for sure.

:confused1: come to think of it maybe it was Angels I was thinkign of.

Time to go back and look at the tyre arguments threads.  :)