[SOLVED] "is this tank slapper"?

[keratos]

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
 

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

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 

[trudd]

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!

[keratos]

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.

[Fazer Forever]

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!!!

[unfazed]

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 

[keratos]

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 

it is already gone past that stage pal  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 

[unfazed]

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 

it is already gone past that stage pal  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

The underlined bold bit above is what bothers me the most 

[keratos]

yeah unfazed, maybe i should just ride it like you suggest 

[Sannox]

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

[keratos]

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.

[keratos]

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


 

[unfazed]

I still go with Henry Fords theory Harmonic Resonance,  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.

[keratos]

I still go with Henry Fords theory Harmonic Resonance,  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?

[andybesy]

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

[keratos]

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 

[unfazed]

I still go with Henry Fords theory Harmonic Resonance,  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

[keratos]

Just me being non mechanical minded and not understanding
I've since googled and now comprehend
 

[unfazed]

 

[Fazafou]

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

[keratos]

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

[paulchucky]

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 

 
no way take my hands off at 100mph n not a twitch    if it wobbles theres sumet not right ! find it sort it

[keratos]

...
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

[unfazed]

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.

Many standard wheels are out of balance by up to 30 grams from the factory due to manufacturing tolerances.

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.

[keratos]

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

[unfazed]

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