funny noise on acceleration

had a nice little ride out yesterday but noticed that on accelaration i get a funny like bearing noise as soon as u leave of the throttle it goes. even steady throttle theres a noise, if anyone has any ideas would be greatfull tbh,

on a diffrent note not sure if its related but on the front sprocket there is no nut holding it on it just slides on and thats it personaly i think thats abit odd tbh its an 03 plate if that makes any diffrence. i have have had this noise since i changed chain and sprocket set thinking front sprocket may be moving seems all the splines are clean and not full of sticky grease?

and when bike is cold the chain is quite tight and as soon as ive done 10-15 miles and then check it its perfect.

If I've just read that correctly and there is NO NUT holding your front sprocket on STOP!!!!! No not ride the bike another inch. That us a potential fatal situation waiting to happen. There should be a nut and a locking washer on the sprocket.

Imagine if that came off at speed the consequences would be horrific, the sprocket rotating at speed will chew through metal, plastic, FLESH, the chain could come off either locking up your back wheel, chewing your back wheel to pieces or flipping over through your helmet and across your back. Seriously a chain failing at that speed would take your head off.

Forget the other problems for now and get that sprocket sorted, the consequences will be catastrophic if you don't.

yee i sort of started thinking and looked in haynes manual seems i got one naw ive been ridding it since december an thers never been a nut on there. feal quite bad now seems as i was giving it some stick yesterday. think ill order one on my coffe break

just thinking about it and abit of common sense i worked out that the cover is not designed to stop it. BACK TO SCHOOL I THINK.

OMG!! Aside from the splines on the sprocket shaft, did you not also notice a thread?!

It is not uncommon for the nut to vibrate off of the shaft but, as stated above, the consequences range from mechanical damage to injury and death.

If you have done any serious mileage with the nut missing then there is a good chance the splines will be worn on the sprocket and/or the shaft - if not then a small prayer of thanks to whoever guides and looks after you is in order because they have been REALLY looking out for you recently!

owen.dyer146 wrote:just thinking about it and abit of common sense i worked out that the cover is not designed to stop it. BACK TO SCHOOL I THINK.

Yeah that cover is aluminium so at about 70mph the sprocket would have chewed through that on its way to your leg.

As Weasley said someone's been looking after you, just glad you discovered this before they turned away for a moment!!

MMM just orderd the locking nut and tab if the shaft is worn i know a gearbox specilist that can sort it out but all being well ill have nut by weekend . any advice on the chain tension?

You're one lucky fella.

I've had the front sprocket nut come off twice on me, the second time I got it welded on as my engine needed to be split at some point to fix second gear anyway.

No idea why but this seems to be something that can happen on the cat, read many storied about it happening, never had a problem on any of the other bikes I've had thought.

Would a bit of threadlock not prevent the nut coming off?

No!....... the only thing is the proper clamp that bends up and physically holds the nut from ever turning

YZFJohn wrote:Would a bit of threadlock not prevent the nut coming off?

Nope, you get lock washers that go over the spline which are shaped on the internal diameter to fit in the grooves in the spline and then the nut goes on and gets tightened up, then you bend one or two of the edge of the washer over the side(s) of the nut to help prevent it becoming undone.

But for some reason it doesn't always work. No idea why.

Tell you what though, when I got mine welded on it never came off

took the front sprocket cover off first thing thismoarning theres no scooring marks on cover so im hoping that the noise is just the chain out of line slightly hopefully have parts by weekend to find out!

I would use a bit of treadlock if i were you.
In my case the lock plate was perfectly intact and did'nt move an inch but the nut was loose, on closer inspection we found that the threads on the nut were bent as if the nut was pushed with alot of force.

Make sure the thread on the shaft is clean all the way around.
Measure your shaft if the diamiter is smaller than 17.5mm you may need a new shaft,"or use the welding option" There was a thicker replacement nut released the original was 9mm wide and the replacement is 12mm wide because of the thread problem.


Also make sure you torque her down correctly those retainer nuts are a bit flimsy and have a very fine thread for some reason.

If memory serves it has to be torqued 75nm.

Good luck to you

may use threadlock and seems i have a welder may put a quick spot on the nut extra seafty.

I just want to say that I only had mine welded because my output shaft was buggered anyway and was going to be removed from the engine so I would never have to remove it.

It's not something I would have had done otherwise. Just had to throw that in as a disclaimer

; )

yeee thats fine just 2 spots on nut that i can get of easy in future to change sprockets peice of mind more than anything tbh.

https://s1263.photobucket.com/albums/ii634/owendyer146/?action=view&current=e31e3c05.jpg

https://s1263.photobucket.com/albums/ii634/owendyer146/?action=view&current=e31e3c05.jpg#!oZZ2QQcurrentZZhttp%3A%2F%2Fs1263.photobucket.com%2Falbums%2Fii634%2Fowendyer146%2F%3Faction%3Dview%26current%3D7c3455c5.jpg

think that should sort it just in need for some weather for a spin

update better krimped locking tab and 2 spots of weld

fine job..it should be much safer