old - Fazer Owners Club - old
Bikes, Hints'n'Tips => FZS600 Fazer => Topic started by: keratos on 28 July 2014, 10:16:42 am
-
I have heard of something called "tank slap" where the handlebars oscillate left to right, sometimes violently and at speed.
I bought my fazer two weeks ago from a local shop (not dealer) with a new 12 month MoT.
When I ride , on any road, hands off the bars (6am so no other traffic!) at any speed 5, 10, 50MPH the handlebars start to oscillate slowly at first getting faster. Maybe a turn every 2 seconds upto quite vigerously. If I put my hands on the bars I can easily control it - not much resistance - at any speed but my fingers get very numb. (another post on the forum)
Question:
1. Is this tank slap or something else?
2. What causes it? Is causing it?
3. Is it safe?
4. Should it have passed an MoT
I'm thinking of going back to the shop so could do with some replies.
-
its a form of tank slapper yes but its a mechanical issue, it will pass an mot as they don't test bikes by riding them no handed, the issue could be one of many thinks, had this on my xj 600, was fine with my hands on the bars but after 30mph hands off my bars went insane! couldn't find what was wrong but after changing my front tyre it was fine but eventually starting coming back but not as bad.
Its probbaly down to your front wheel being off balance, get the wheel off stick the spindle through it and put it on a set of axel stands and spin the wheel, if it wobbles there is your issue.
it is perfectly safe aslong as you hold onto your bars, i rode like it for about 4 months before i fixed it but i didn't set out to fix it.
-
go back to the shop matey...un-safe...wheel balance,wheel bearings,swingarm bearings,tyres and pressures,forks...could be any of the above ,go back and have a chat ,see what they say ;)
-
Tank slapper----------- oh I always thought that was refering to your danglies "slapping " the tank during any big "moment"
-
I recently addressed a "tank slapper" wobble. Here's what I learnt.
Like yours only an issue without any pressure on the bars, but mine was different to yours in that:
1) It was stable at most speeds but occurred consistently and immediately between 40 and 45 mph.
2) It would immediately (at these speeds) wobble very fast, say 4 oscillations per second (none of the starting slow then building in speed you describe)
As soon as speed dropped below 40 mph nice and stable again subject to road surface.
I took it to my local Yam dealer to get checked out and asked that they check all the bearings etc for safety. They told me:
1) It wasn't unsafe (I mean due to failed bearings etc, not that the wobble wasn't unsafe)
2) It's usually caused by the top box rack (even without box attached) or uneven front tyre wear (although there are many other causes, but those are most common)
3) They could change the front tyre (it was due anyway) and slightly loosen steering head taper bearing to see if it helped (but no guarantees)
4) Bearings were fine (visual inspection of from wheel, others checked for play)
Having had the front tyre changed it's a lot better. Not gone completely, but minimal enough that it's not a practical problem. Nice to have had the bike checked safety wise too.
I suggest that:
1) your wobble doesn't sound too bad given that it starts quite slowly
2) But if it makes you uncomfortable get it checked out and try to fix it
Start by looking closely at your front tyre. How many miles has it done, and how is the wear?
Do you have a rack?
Andy
-
I don't think I've ever had a bike that didn't do that.
Tyre wear, brake disc alignment etc etc etc etc will all cause a tiny wobble of the bars.
The fact is you shouldn't ride like that so unless it's noticeable with your hands on the bars don't worry about it :)
-
go back to the shop matey...un-safe...wheel balance,wheel bearings,swingarm bearings,tyres and pressures,forks...could be any of the above ,go back and have a chat ,see what they say ;)
+1. Take it back and ask them to sort it - couple of months time it could get worse and by then they'll tell you to feck off!. Get them to look at it as soon as fella.
Good luck.
-
Ok. Taking it back to PB Motorsport in Blackpool; see what they say after work. I will report back.
Thanks everyone.
-
Good luck matey ;)
-
THIS is a tankslapper.....
[Motorcycle Accident]TT-Tankslapper-19sec (http://www.youtube.com/watch?v=LZ1srcQMa_0#)
-
Mine is a tanktwitcher in that case
-
Just got back from the bike shop. Not the one I bought from but the guy who does all major service/repair work, MoT and alike for last 10yrs or so....CHRIS at CS Cycles of poulton-le-fylde . Chris summarily inspected bearings ,head, races etc and believes it's the wheel balance. We noticed the weights, well THE weight on front wheel is only on one rim side,not both. He was on his way home and has shut down so will do a thorough look and rebalance the front tomorrow. I will report back.
Still riding....s.l.o.w.l.y.!
-
Don't think it is a serious problem, mine was doing it since its first tyre change and still does it 84000miles later.
Balancing the front wheel improves it for a good while but it is always there. I remember years ago all fords cars had it at 40Mph and ford said it was harmonic resonance :)
Since I do all my own work and know everything is ok it never bothers me.
90% of the 600 I have ridden do it.
Never was sure why one would want to take their hands off the bars while riding at any speed :eek
-
Don't think it is a serious problem, mine was doing it since its first tyre change and still does it 84000miles later.
Balancing the front wheel improves it for a good while but it is always there. I remember years ago all fords cars had it at 40Mph and ford said it was harmonic resonance :)
Since I do all my own work and know everything is ok it never bothers me.
90% of the 600 I have ridden do it.
Never was sure why one would want to take their hands off the bars while riding at any speed :eek
cheers bud. yes, Ive read your many posts through this forums and you certainly have a lot of demonstrable experience and good advice. thanks for words of comfort.
BTW, FWIW, the hands-off was a suggestion caveated with lots of warnings about empty roads, early hours of the morning, no one around, wide quiet road, slow walking speed and gradually increasing, hands strong and close to the bars ready to take control...all that...a suggestion to diagnose whether it was a speed issue. The other suggestion was to take the wheel off and spin on a wheel stand - but I dont have one so took the racier option! It does not appear to be speed related. As said, balancing looks the candidate and the bike is in the shop tomorrow. The oscillation is less severe than the video above, but its unnerving at speed and needs sorting.
-
well, had it balanced (it was 15g out on one side) and new front wheel bearings
Still the same; darn it.
Will be taking it back to the shop for Chris to test ride which he didnt do today. Cost me £30 too.
What I would say is that I can control the bars with one hand holding the grip with two fingers of the one hand and very gently. Take this ever so slight pressure off and the bar starts to slap. ???
-
Sounds very like what mine has been doing for the last 80000miles :)
Check the wheel bearings front and back just to be safe .
-
Sounds very like what mine has been doing for the last 80000miles :)
Check the wheel bearings front and back just to be safe .
?? As said, i had the wheel balanced AND new bearings fitted ??
-
With all the work you seem to be doing on it, i'd be inclined to get the fork oil replaced as well.
Low, very old or uneven oil levels could cause the wobbles.
If you consider it, 15w instead of 10w oil makes the front end feel much more stable in my opinion, plus at least you'll know it's been done.
-
Sounds very like what mine has been doing for the last 80000miles :)
Check the wheel bearings front and back just to be safe .
?? As said, i had the wheel balanced AND new bearings fitted ??
What about the rear??
-
Sounds very like what mine has been doing for the last 80000miles :)
Check the wheel bearings front and back just to be safe .
?? As said, i had the wheel balanced AND new bearings fitted ??
What about the rear??
ah sorry , erm well the rear bearings replaced when I bought the bike ; wheel alignment also checked. hence focus on front end. weird how two fingers resting gently on one handle can prevent what otherwise becomes a violent oscillation,
-
Keep your hand on the bars and forget it, :lol
-
yep that is an option, but I've never experienced it before in 30 years of riding and many many bikes - quite alarming and one immediately thinks of my own safety and those of other road users and pedestrians god forbid something went wrong at speed.
I still want it checked over and will do this Thursday when it goes back into the shop.
-
Always good to check to be safe, but don't let it put you off riding it. :)
I have seen an indicated 140 on my clock 2 up, been all round Ireland, UK, France and Spain touring two, been on track days, had some spirited high speed runs with friends and it has never been a problem. :)
-
Mine does it too under hard acceleration. Just don't take your hands off and there's no problem. Like you said the slightest of pressure on the bars and it doesn't happen. Don't know why you'd want to take both hands off anyway unless you were showing off your skills to ladies :lol
-
Had the same on my 2001 FZS, after reading up on the forum I replaced the front tyre, no more wobble, I think I read that they can sometimes do it after the tyre has done around 4k miles
Trouble is it costs you to see if it is the cause, but like others have said it could go to the red line with no issues as long as you have a light grip on the bars
Jonesy
-
With all the work you seem to be doing on it, i'd be inclined to get the fork oil replaced as well.
Low, very old or uneven oil levels could cause the wobbles.
If you consider it, 15w instead of 10w oil makes the front end feel much more stable in my opinion, plus at least you'll know it's been done.
Is there an article or a HOWTO you can recommend. I have never done this before, limited toolkit, would need guidance and video/image support? thanks? I do not understand this one as it seems to be a bigger job than just chaning oil and I'd like a more concise easy to follow guide - just for the first time http://fazerowners.yuku.com/topic/23188/HOWTO-Forks-Seals-Bushes-and-Oil (http://fazerowners.yuku.com/topic/23188/HOWTO-Forks-Seals-Bushes-and-Oil)
Mine does it too under hard acceleration. Just don't take your hands off and there's no problem. Like you said the slightest of pressure on the bars and it doesn't happen. Don't know why you'd want to take both hands off anyway unless you were showing off your skills to ladies :lol
To test what would happen. I dont ride this way obviously - it was just a quick 2 second test repeated on different roads and different conditions, same result. At my age I'm past caring what the ladies think :z
-
Do you have a top box or bars that pull back further than standard?
My understanding is that bikes with close to 50/50 weight distribution display this behavior. FJ1200's are renowned for it and both my FJ and Fazer do it but it doesn't bother me, I just don't let go!
-
nope I do not.
what I am hearing is that it is a common issue and foccers are either aware of or deal with, the issue. for me, it's not right and I'd like to get to the bottom of it; won't stop me riding but I will figure this out and identify root cause. it cannot be right that all the natural forces attacking the bike and working with the bike, make it this unstable; just a personal quest. we shall see what the service shop thinks tomorrow.
-
I've owned my bike for 12 years and 40 000 miles. Have experienced this once only and I believe it was due to front tyre wear.
Went away when it was changed and has never re-appeared. Never went back to Bridgestones either!!!
-
nope I do not.
what I am hearing is that it is a common issue and foccers are either aware of or deal with, the issue. for me, it's not right and I'd like to get to the bottom of it; won't stop me riding but I will figure this out and identify root cause. it cannot be right that all the natural forces attacking the bike and working with the bike, make it this unstable; just a personal quest. we shall see what the service shop thinks tomorrow.
It will drive you nuts :lol
-
nope I do not.
what I am hearing is that it is a common issue and foccers are either aware of or deal with, the issue. for me, it's not right and I'd like to get to the bottom of it; won't stop me riding but I will figure this out and identify root cause. it cannot be right that all the natural forces attacking the bike and working with the bike, make it this unstable; just a personal quest. we shall see what the service shop thinks tomorrow.
It will drive you nuts :lol
it is already gone past that stage pal :D and I'm a stubborn git (software engineers usually are) and I like to know how/why things work. When I was a kid I used to enthral my parents by means of dismembering compendiums of electronic gadgets to see how they work . needless to say they never worked again :rollin
-
nope I do not.
what I am hearing is that it is a common issue and foccers are either aware of or deal with, the issue. for me, it's not right and I'd like to get to the bottom of it; won't stop me riding but I will figure this out and identify root cause. it cannot be right that all the natural forces attacking the bike and working with the bike, make it this unstable; just a personal quest. we shall see what the service shop thinks tomorrow.
It will drive you nuts :lol
it is already gone past that stage pal :D and I'm a stubborn git (software engineers usually are) and I like to know how/why things work. When I was a kid I used to enthral my parents by means of dismembering compendiums of electronic gadgets to see how they work . needless to say they never worked again :rollin
The underlined bold bit above is what bothers me the most :lol
-
yeah unfazed, maybe i should just ride it like you suggest :b
-
Had it on my 2002 Fazer, hands off one day to stretch my arms, was doing 40 and the handlebars started to slowly wobble and got progressively worse, building up to a tank slapper, hands back on stopped it, was wondering all sorts, tyre pressures were spot on, I wondered about alignment of the frame, turned out to be the front tyre, odd wear due to having been run at too low a pressure prior to my buying the bike, had various tyres on the front and not had a problem since, I'd say make sure the head bearings are good, front wheel bearings too but most of all, tyre pressures and balance should be spot on, after that, hmmmmm
-
Had it on my 2002 Fazer, hands off one day to stretch my arms, was doing 40 and the handlebars started to slowly wobble and got progressively worse, building up to a tank slapper, hands back on stopped it, was wondering all sorts, tyre pressures were spot on, I wondered about alignment of the frame, turned out to be the front tyre, odd wear due to having been run at too low a pressure prior to my buying the bike, had various tyres on the front and not had a problem since, I'd say make sure the head bearings are good, front wheel bearings too but most of all, tyre pressures and balance should be spot on, after that, hmmmmm
the tyre has been mentioned by several foccers. thanks. its defo something I will look at.
-
Just got back from the service shop.
I was worried about wheel alignment, front end, forks, headstock...
Anyway Chris from CS Cycles , wonderful service/repair chap and a damm good track boy too, has took it out for a ride - a good half hour - upshot it..
Nothing wrong. Chris is wondering what I'm moaning about. He said if you can control it with my pinkie (as I can) then it isnt something serious, was it!? he said he has seen this on fazers before with uneven tyre wear although mine isnt too bad apparently. But all in all, just a "feature" of this bike I'm told.
So, that's it. nowt to worry about. As most foccers said.
and...I've just noticed this in HOTPOOP
http://foc-u.co.uk/wiki/index.php?title=Front_Wheel_Wobble_-_description,_and_possible_causes (http://foc-u.co.uk/wiki/index.php?title=Front_Wheel_Wobble_-_description,_and_possible_causes)
:o
-
I still go with Henry Fords theory Harmonic Resonance, :lol which is probably close to the mark due to the almost 50/50 weight distribution of the FZS600.
It is a bit like the castor effect and the front wheel due to rake and trail operates in a similar fashion to the castor. :)
-
I still go with Henry Fords theory Harmonic Resonance, :lol which is probably close to the mark due to the almost 50/50 weight distribution of the FZS600.
It is a bit like the castor effect and the front wheel due to rake and trail operates in a similar fashion to the castor. :)
Eh?
English?
-
Pretty sure mine started when I fitted the top box rack, and was later exaggerated by uneven front tyre wear.
Changed the tyre and much better now but still a little bit of it there, even without any box on, just the rack.
Reckon it's just the extra weight on the rear?
Andy
-
mine has a top box too.
not taken it off though to test.
I might try this but in no hurry now that the experts here and in the service shop have told me to stop worrying ;)
-
I still go with Henry Fords theory Harmonic Resonance, :lol which is probably close to the mark due to the almost 50/50 weight distribution of the FZS600.
It is a bit like the castor effect and the front wheel due to rake and trail operates in a similar fashion to the castor. :)
Eh?
English?
That was the Queens English? what English do you require :lol
-
Just me being non mechanical minded and not understanding
I've since googled and now comprehend
:o
-
:thumbup :)
-
mine has a top box too.
not taken it off though to test.
I might try this but in no hurry now that the experts here and in the service shop have told me to stop worrying ;)
Glad you're happy now :)
-
mine has a top box too.
not taken it off though to test.
I might try this but in no hurry now that the experts here and in the service shop have told me to stop worrying ;)
Glad you're happy now :)
I wouldnt say I'm happy but I just live with it as recommended by wise foccers here and my trusted shop mechanic
-
Don't think it is a serious problem, mine was doing it since its first tyre change and still does it 84000miles later.
Balancing the front wheel improves it for a good while but it is always there. I remember years ago all fords cars had it at 40Mph and ford said it was harmonic resonance :)
Since I do all my own work and know everything is ok it never bothers me.
90% of the 600 I have ridden do it.
Never was sure why one would want to take their hands off the bars while riding at any speed :eek
no way take my hands off at 100mph n not a twitch if it wobbles theres sumet not right ! find it sort it
-
...
no way take my hands off at 100mph n not a twitch if it wobbles theres sumet not right ! find it sort it
like i said above...
http://foc-u.co.uk/wiki/index.php?title=Front_Wheel_Wobble_-_description,_and_possible_causes (http://foc-u.co.uk/wiki/index.php?title=Front_Wheel_Wobble_-_description,_and_possible_causes)
-
Point appears to have been missed, it only appears to happen around 40mph, it does appear to happen above 50 or below 30. On any bike I have ridden including my own it has always been around the 40mph mark.
This issue has been around for years and frame design plus the harmonic resonance of the components involved can exacerbate it.
Watch the chatter problem in racing which is exacerbated by super stiff frames and is caused they think by harmonic resonance. Yamaha changed the stiffness of the frame in MotoGP to try and reduce the effect as changing the stiffness changed the point of harmonic resonance at a given speed
An unbalanced wheel can cause it and I do not mean unbalanced with a tyre on, but unbalanced bare wheel. :eek
Many standard wheels are out of balance by up to 30 grams from the factory due to manufacturing tolerances. :eek
On one particular fazer I checked, the imbalance of the bare wheel with discs attached was 5 grams. It did not have the problem. My original front wheel with discs attached was 25 grams out, but the new wheel replaced after an accident (insurers paid) was 12 grams out without the discs and was 14 grams out with the discs on and the problem is not as pronounced with this wheel.
Balancing wheels is not a perfect science as you cannot add weight to the exact point it is required. Unless you can get a machine to detect the inbalance of either side of the rim like the wider car wheels there will always be the shake possibility on the fazer.
A super quick steering bike is much more prone to the problem (which is why many race rep bikes with quick steering use a steering damper) and the 600 as a pretty quick steering bike it is more prone to it..
It is quite possible that those who have fitted a 120 section front tyre may not suffer from the problem as it slows the steering, I am surmising as I have never checked it.
-
I get it at any speed. starts off as a gentle wobble but leave it along and it gets into the resonance oscillation we call a slapper
anyway, been checked out and safe to ride
cant be that bad as two fingers gently on the right or left grip stops it.
I'm riding regardless now
-
Out of curosity, next time you change the front tyre ask the mechanic to check the wheel balance without the tyre and all balance weights off.
What tyres are you using? I found the sports tyres were worse than sports touring tyres as they sharpened the steering, but I prefer the sharper steering. It does not bother me, since there is no serious mechanical issue
-
Out of curosity, next time you change the front tyre ask the mechanic to check the wheel balance without the tyre and all balance weights off.
What tyres are you using? I found the sports tyres were worse than sports touring tyres as they sharpened the steering, but I prefer the sharper steering. It does not bother me, since there is no serious mechanical issue
just had it balanced, but with tyre on, kind of misses the point with it off I would have thought.
BT10s - whatever designation they are (sports/tourer/tortoise)
-
Harmonic resonance of different materials.
-
Harmonic resonance of different materials.
Mmm. So can a specific tryre reduce this phenomena ?