My simple Front Sprocket Fix

[packie]

Fitted a new set of chain and sprockets last week and fitted the new nut with thread lock. When torqing the nut up, I felt that after torqing carefully up to about 60nm of pressure that the nut was in danger of going to strip from the shaft. So I left it at that and didn't dare to push it any further. But that left me still a bit paranoid about even the new nut working itself free.

I got a DID chain and JTS (I think) sprockets from M&P. The front had holes drilled into it so I did a McGyver and looped some wire through the holes and criss-crossed it over the nut. It would take excessive force outwards from the shaft to break this wire and force the nut off. I don't think there is that force there from my own experience. My front sprocket stayed on without a nut at all for over 1,200 (known) miles from just mere rust, balance, and with the grace of God!!

So I don't think the sprocket pushed the nut off. I think these nuts just sometimes work open for whatever reason and just vibrate off the shaft rather than any excessive force pushing them off. So the wire should be secure enough and might help to give those with a similar front sprocket a bit of added peace of mind without having to do a big DIY engineering job..

Heres a piccie of my McGyver for those who have a similar type sprocket.

[Ruby Racing]

Nice job sir.


Shouldn't the metal tab under the nut be bent onto a couple of the flat surfaces as well though?

[darrsi]

Nice job sir.


Shouldn't the metal tab under the nut be bent onto a couple of the flat surfaces as well though?

Agreed, that's the point of the safety washer in the first place, to supposedly stop the nut from undoing!
Good idea with the wire though!

[packie]

[quote author=Ruby Racing link=topic=6468.msg60184#msg60184 date=1361809076]
Nice job sir.


Shouldn't the metal tab under the nut be bent onto a couple of the flat surfaces as well though?

Agreed, that's the point of the safety washer in the first place, to supposedly stop the nut from undoing!
Good idea with the wire though!
[/quote]

Well my tabs don't line up. The one you are looking at lands on a corner of the nut. The other tab lands flush on the nut body itself, and is secure fully and which you can't see in the photo. The nut still can't get by the tab you are looking at...I tried it. And it certainly ain't moving from the other tab. Throw a bit of thread lock and my wire into the bargain and its a cert that this nut is going nowhere. Is your tabs flush on both flat parts of the nut??

[stevierst]

I like it! Helicopters are held together with the stuff, so your bike should be safe. I would bend the tab washer as well though, it will go with a bit of brute force. :-D

Sent from my HTC One X using Tapatalk 2

[wezdavo]

You need to bend those tabs over bud, dont worry about them lining up just get them wacked over..

[unfazed]

Best of luck, hope it lasts. You would want to bend over the tabs.

[Fazerider]

It's not something I'd do. Can't see that bit of wire coping with vibration, high rpm and salt spray for very long and there's the risk that it'll mangle an O-ring once it gets loose.
The big nut, screwlock and tab washer will do the job fine.

[bozboz]

You need to bend those tabs over bud, dont worry about them lining up just get them wacked over..

Second that, get a flat blade screw driver under the washer to bend it up on at least two flat surfaces of the nut(with some hammer assist if needed). TBO that wire looks a little wimpy for the job.

[trudd]

One trick I was shown is to use a pair of pipe grips to bend the tabs over. They make life really easy and do a great job.


This type:

[Dead Eye]

I have a wide punch (more like a flat head screwdriver compared to standard punches) which I used in conjunction with my hammer. Did the job nicely

I'd warrant caution using a screwdriver to bend the tabs as some can be flimsy as they aren't designed to take stresses along that axis and can snap - I've managed to do this before on other jobs

[packie]

It's not something I'd do. Can't see that bit of wire coping with vibration, high rpm and salt spray for very long and there's the risk that it'll mangle an O-ring once it gets loose.
The big nut, screwlock and tab washer will do the job fine.

Personally, I seriously think that the wire I have on will hold but one is free to put tougher wire on or use another method.

The whole point of my post was that IMO, some form of protection for the nut should be put in place. The member "Unfazed" have a fantastic fix in the downloads.

Mine is more simple but i'm confident will still do the job. I certaily ain't going around being Yamaha's guinea pig for the new nut and have nothing to catch the nut from coming off the shaft in the event of another catastrophic failure. I was lucky once. Yamaha could have killed me and 50% of other riders on this forum. I am not going to give them the opportunity again. I was riding up to speeds of 80-90-100mph without a nut on my sprocket. Could you imagine what would have happened if the whole sprocket came off?? And all we are relying on here is a similar nut with a bit more thread and a bit of faith in Yamaha that it will do....no thanks!!

So I rather take the risk of a mangled o-ring than a mangled me! As I said, there are other fixes out there if you don't want to use my wire fix. But please do something. My nut didn't fall off over night. I had 23k up on my bike.

To those who are concerned that I had only one tab washer properly in place.......

....one tab washer is good enough believe it or not. The nut wouldn't have the force to lift even one tab when is bent down on the nut properly along with proper torque and threadlock. Not that i'm recommending using one tab only. But I would like to point out that there are many many bikes that don't even have tab washers at all on them and are just secured by the proper torque settings and threadlock. The tabs were not the problem.

The problem was the flimsy threads and material of Yamaha's nut. Out of 50% of the owners here who lost their nut, I'd say all of them had their two tabs properly in place along with proper torque and maybe even threadlock thrown into the bargain.

The nut didn't force it's way past the tabs. The problem it seems was that the nut with its flimsy material and lack of enough thread stripped over time, then backed away far enough from the shaft that the tab washer came off the shaft too, and both happily spun around until exiting stage left. You could have had ten tabs secured onto the nut and it still wouldn't have prevented the catasrophic failure that happened.

But once again....the point of my post got lost over my tab. The message that I was conveying was that if I was peeps here, I'd go suss out some way of blocking the end of the shaft for the nut and sprocket to fall off if Yamaha's new nut have a similar catastrophic failure. Your life could depend on it.

[Fazerider]

Do you have the damper plate on your sprocket cover? I know some Fazers were sold without it, I was lucky that mine came with one (though not the damper rubber that should have been underneath). When my sprocket nut came loose it wasn't able to come off the end of the shaft because the plate is near enough to prevent that (even with the old, thinner nut).
It first happened to me before Yamaha had acknowledged there was a problem. I replaced the nut and washer several times before deciding that the soft nut material and fine thread meant it wasn't up to the job... at which point I welded the bugger on. However, my last 50-ish thousand miles I've done has been with the bigger nut rather than a welded solution.
So I'm confident in the safety of it: even if the nut fails it won't let the sprocket fall off the splines because the damper plate will keep everything on the shaft.

[reillypadraig]

Nice job packie, well wear

Oh u going to the rds on Friday? Motorcycle show http://www.irishmotorbikeshow.com

[packie]

Do you have the damper plate on your sprocket cover? I know some Fazers were sold without it, I was lucky that mine came with one (though not the damper rubber that should have been underneath). When my sprocket nut came loose it wasn't able to come off the end of the shaft because the plate is near enough to prevent that (even with the old, thinner nut).
It first happened to me before Yamaha had acknowledged there was a problem. I replaced the nut and washer several times before deciding that the soft nut material and fine thread meant it wasn't up to the job... at which point I welded the bugger on. However, my last 50-ish thousand miles I've done has been with the bigger nut rather than a welded solution.
So I'm confident in the safety of it: even if the nut fails it won't let the sprocket fall off the splines because the damper plate will keep everything on the shaft.

Naw, Fazerider. My 02 foxeye didn't come with a dampener. That would be classed as another peace of mind fix too. I think its on earlier models that have the dampener plate that you speak of.  Unfazed did a mod for that in the download section for the later model. That man is the REAL McGyver!!

Apologies if I'm sounding a bit over the top on this, but only last year I had a simple 20mph spill and I ended up with a nasty leg injury and out of work for 3 months. I certainly don't want my whole life dependant on one replacement nut.

This morning I banged that other tab into place (not that it makes a difference!) and fitted stronger wire. I'd say that the nut should stay on it's own, but my little McGyver job is only a simple added safety precaution that will also allow me to not think about it anymore.

Cheers....

[darrsi]

mash    :lol   

[packie]

:fish ....... :evil

[pointer2null]

Got the tabs on my sprocket nut bent over correct but the nut still works loose - the only explanation is the threads are slipping over each other. Periodically I re-tighten it.

[darrsi]

Got the tabs on my sprocket nut bent over correct but the nut still works loose - the only explanation is the threads are slipping over each other. Periodically I re-tighten it.

With the new nut?

[pointer2null]

yep. new nut, washer and sprocket.


My guess is that the dimensions of the nut/shaft are wrong (design flaw) so that the nut is just slightly too big and when hot (expanded) can jump threads