Cautionary tale

[MikeL]

Here's something to think about:

I did my first Track Time at Pukekohe on Sunday. Had an awesome time, can't wait to go again, but that's another story. Went with a mate (not a KBer but an experienced rider although like me he had never been on the track before). At the bike inspection he was told the chain on his Fireblade was a bit tight so he adjusted it. We did 3 sessions and then during the next break he asked another guy to have a look at his bike and give him some advice about his suspension settings. The guy then exclaimed "Holy Shit" and pointed to the axle nut which was just about to come off. It was literally hanging by a thread. After we had psyched ourselves out speculating on what would have happened if the wheel had come off at various points round the track, we tried to work out why the nut was loose. I had sat on the bike for him while he did the adjustment so didn't see what he was doing and can't say whether he tightened the nut properly. He says he can't remember doing it up but if he had it would have been tight, so the most likely explanation is that he got distracted and simply forgot to tighten it. He was understandably quite shaken up by the whole incident.
Now here's the most important question: was it chance, coincidence, fate or something else that prevented a disaster??
Answers from CK and Zed will be particularly appreciated!

[curious george]

Dunno. Just damn lucky it was caught before it broke
The wheel nut gods must be upset.

[Jackrat]

Hmmmmm,Me thinks he would of worked it out when he was left with a split pin to put somewhere.He did have a split pin yeah???
Sorry Mike couldn't help that.
But anyway what stopped it coming off?? ,Don't belive in fate,Maybe he was being watched over,Maybe it was luck.
What ever, it's sure something to think about.
I hope the next thing he bought was a split pin

[Antallica]

Wasn't his time to go.... man that would scare the shit out of anyone.

[Motu]

This sort of thing happens a lot in the repair game - makes us look like a bunch of dickheads and can be bloody dangerous too! Alloy wheels coming loose is the latest thing going wrong.

Of course we have to blame the guy who tightened the nut - they always say ''but I did tighten it!'' yeah right.But it's happened to me too,and I know I tightened the thing correctly,sometimes having to pay a towage and out of town repair bill.

What's happening here? it never used to happen on the old British and Australian cars we worked on years ago...are we getting old and doddery? For me I think Japanese fasteners can't take too many stress reversals,or when tightened to a possibly incorrect torque they will loose tension and come loose,it just happens too many times to be poor workmanship.A bit of crap under bolt head or on the threads - with the alloy wheels,we no longer just slam them up tight as we can get them with a hammer gun,we use a torque limiter or a torque wrench,but with the lower,but correct torque,the wheel doesn't seat correctly and loosens up after a few days - like,if we forgot to tighten the wheels they would be loose when it left the shop,not a week later.

But for your axle bolt we have to allow for heat of the moment - a nervous rider on a track day is not very focused,I'd say he may have missed that one.And as Jackrat pointed out....the split pin? if the pin was in it wouldn't come loose,no matter what.

[GPz]

It would be a timely reminder when any work/adjustments are made on your bike.
Even if it has been serviced by a reputable Dealer.
They can miss things like not tightening up the pinch bolt on the front axle and routing one of the spark leads between the frame and the tank. I found both faults after i had riden from Tauranga to Wanganui on boxing day, a couple of years ago. the loose axle wasn't noticable but the miss in the engine was what made me check the bike over.
Second note, don't get your bike serviced the day before you take it on holiday.

[wkid_one]

Don't know of many sports bikes running cotter pins on the main axle bolts.

Can drill them yourselves.

I would hasten to at that at the track - he would have been unlikely to have a torgue wrench with him either?

My best guess is that he didn't tighten it up at all. As with heat and friction - metal expands - so if anything - even done up partially tight - after three sesssions - it would have been unlikely to become as loose as that.

[bluninja]

Don't know of many sports bikes running cotter pins on the main axle bolts.

Can drill them yourselves.

I would hasten to at that at the track - he would have been unlikely to have a torgue wrench with him either?

My best guess is that he didn't tighten it up at all. As with heat and friction - metal expands - so if anything - even done up partially tight - after three sesssions - it would have been unlikely to become as loose as that.

LMAO at WKID....if what you say is true, then all this lockwiring of racebikes is a waste of time...V-twins especially don't vibrate things loose till they fall off.

Nuts can work loose over time....people should probably check key items on their bike each week to make sure they haven't loosened and do a pre-ride check so they don't ride off with flat tyres, loose/tight chain, no brakes, or bits just about to come off.

And as to what Motu said....I've always been told to re-check wheels nuts for tightness after you've driven the vehicle following your wheel being taken off. Like most people I often forget.

TTFN

[merv]

Now I haven't sulked round the pits lately or been to a track day but I was of the understanding that the days of scrutineering were over at MNZ events - liability issue being that if their scrutineer said the bike is OK then he is liable if something goes wrong and he can be shown to have missed it.

Now is that the case? If so why are they still scrutineering at track days?

How tight was the chain that it needed adjusting i.e. loosening off? Was the guy being a bit pedantic to ask for that?

Now he is bloody lucky if he did three sessions, because you'd think with a loose nut the axle would have already moved forward under power on the chain side and the wheel could have jammed in the swing arm tossing him off. Fireblades must have pretty good chain adjusters if it didn't allow the wheel to move in the swingarm with such a loose axle nut.

[merv]

It would be a timely reminder when any work/adjustments are made on your bike.
Even if it has been serviced by a reputable Dealer.
They can miss things like not tightening up the pinch bolt on the front axle and routing one of the spark leads between the frame and the tank

That's why I do all my own work if I can to be sure of things. My screw up, my problem.

[bluninja]

Now I haven't sulked round the pits lately or been to a track day but I was of the understanding that the days of scrutineering were over at MNZ events - liability issue being that if their scrutineer said the bike is OK then he is liable if something goes wrong and he can be shown to have missed it.

Now is that the case? If so why are they still scrutineering at track days?

There is still scrutineering at MNZ race meets. The Pacific MCC over the winter just let you sign your Lie Sheet, but they are now scrutineering at the summer series at Taupo. Normally if you are asked to fix or adjust something, you have to go back to have the item rechecked once you've down it.

[Jackrat]

Well I went into the city this morning to buy some bits for my little black consumer of oil seals,While I was there I checked out the rear of about fifty new and near new bikes.So I guess I owe Mike a big (SORRY MATE)
At lest 75% of the bikes I looked at did not have castle nuts on the rear.
They instead had a nylock type nut.
I think next time I will stick to the subject a bit closer

[wkid_one]

LMAO at WKID....if what you say is true, then all this lockwiring of racebikes is a waste of time...V-twins especially don't vibrate things loose till they fall off.

Nuts can work loose over time....people should probably check key items on their bike each week to make sure they haven't loosened and do a pre-ride check so they don't ride off with flat tyres, loose/tight chain, no brakes, or bits just about to come off.

And as to what Motu said....I've always been told to re-check wheels nuts for tightness after you've driven the vehicle following your wheel being taken off. Like most people I often forget.

TTFN

But - I was referring to the fact that there is no way it should be that loose after only 3 sessions at Puke.....without it having BEEN LOOSE in the first place. Read my wording.....

I know first hand as to the dislodging ability of the twin.......

[Motoracer]

This is like the time a couple of weeks back when my front sproket nut came off. I just don't feel safe anymore without a lock pin or some kind of a fail safe mechanism backing up a vital nut or a bolt on a bike.

[wkid_one]

This is like the time a couple of weeks back when my front sproket nut came off. I just don't feel safe anymore without a lock pin or some kind of a fail safe mechanism backing up a vital nut or a bolt on a bike.

Christ......that would have been entertaining