Author Topic: Nasty Surprise (Read 5840 times)

Andy1970 · « **on:** 02 December 2016, 06:34:19 pm »

I was planning to re-paint the rear subframe on the Fazer that I bought in August, due to a bit of rust around the footrest hangers.

Because the chain was right on the wear limit I thought I'd fit a new chain and sprockets at the same time, and I've just found out that SOME F*CKER HAS WELDED THE FRONT SPROCKET NUT ON.

The sprocket's lose on the shaft and the nut has a bloody great lump of weld all over the end of it.

Either way, looks like the engine's going to have to come out a year earlier than I'd planned. What the hell is wrong with some people?

Going to the shop now to buy beer.

Andy

Fazerider · « **Reply #1 on:** 02 December 2016, 07:34:27 pm »

Shouldn't be a major issue, can't think why you'd want to take the engine out, just take an angle grinder to the weld, change the sprocket and weld new nut on.
It was the solution I resorted to before Yamaha recognised there was a problem and came up with a deeper nut. I changed the C&S once more after the first welded-on nut.

fazersharp · « **Reply #2 on:** 02 December 2016, 09:43:40 pm »

Do a search here fella for front sprocket nut and you will find all about it

darrsi · « **Reply #3 on:** 03 December 2016, 06:20:03 am »

Have a meeting with a room full of spot welders, and i think you'll find you have no issues whatsoever.
Just a whole load of over confident front sprocket people.

Bretty · « **Reply #4 on:** 03 December 2016, 03:31:00 pm »

Atleast share some photos of it so we can all point and laugh. :-)

just pop a new one in!

Pandy · « **Reply #5 on:** 03 December 2016, 05:52:51 pm »

It's not so stupid as you think it is.
I heard a lot of stories with that idiot nut unscrewing while driving and the rear wheel stopped. Imagine this situation on a highway and the road isn't straight.
99% a crash is next.

CaptainCazador · « **Reply #6 on:** 04 December 2016, 12:28:51 am »

Quote from: Fazerider on 02 December 2016, 07:34:27 pm

Shouldn't be a major issue, can't think why you'd want to take the engine out, just take an angle grinder to the weld, change the sprocket and weld new nut on.
It was the solution I resorted to before Yamaha recognised there was a problem and came up with a deeper nut. I changed the C&S twice more after the first welded-on nut.

Or worn splines on the output shaft.

tommyardin · « **Reply #7 on:** 04 December 2016, 09:46:28 am »

Just a thought, would welding the sprocket and retaining nut onto the driven shaft from the gear box cause the welded parts to lose its tempering and soften the steel?

There is a problem when welding on cars, so assume it is the same with motorcycles, with the alternator/generator, the voltage from electric welding can fry them, I believe the alternator should be removed from a car before welding , don't know if the same rule applies to the on-board computer, might be wise to ask the question of someone who really knows before going ahead, cos, you just might make your situation worse.

As mentioned in here earlier their has been incidents of the front sprocket coming right off the shaft causing the drive chain and back wheel to lock up, not good.

The original sprocket retaining nut was 9mm thick and Yamaha recognised this was an issue and produced a replacement nut being 12mm thick, this is supposed to cure the problem, well that's OK if the nut has come undone and has been noticed straight away but if the bike has done sufficient miles with the sprocket and nut chattering away it trashes the threads on the end of the gearbox shaft, then it seems you are left with two options a strip down of the engine and replace the gearbox shaft (Expensive and time consuming) or weld the new sprocket on.
So my guess would be the shaft in your gear box is f----d, hence the welding that's been done.

crickleymal · « **Reply #8 on:** 04 December 2016, 10:04:59 am »

Quote from: tommyardin on 04 December 2016, 09:46:28 am

Just a thought, would welding the sprocket and retaining nut onto the driven shaft from the gear box cause the welded parts to lose its tempering and soften the steel?

There is a problem when welding on cars, so assume it is the same with motorcycles, with the alternator/generator, the voltage from electric welding can fry them, I believe the alternator should be removed from a car before welding , don't know if the same rule applies to the on-board computer, might be wise to ask the question of someone who really knows before going ahead, cos, you just might make your situation worse.

I've not heard that before, although that doesn't means it's not true. But the diodes in the alternator ought to be pretty tough, it'd be the ECU that I would say was much more vunerable. I haven't seen anyone remove the alternator when welding any of my cars.

red98 · « **Reply #9 on:** 04 December 2016, 10:08:25 am »

Yeh..me too, damaged thread on the shaft.....regarding welding the new one on, common pratice to disconnect the car / bikes battery when welding

Fazerider · « **Reply #10 on:** 05 December 2016, 12:11:41 am »

I think anyone who does that is just taking folklore as fact.
Provided the welder return/earth clamp is clipped on as close as possible to the weld area, it isn't going to induce troublesome currents in any wiring far enough away to avoid weld spatter. Even if it did, having electrically robust components like the battery and alternator there would actually help delicate bits like the ECU and instrumentation survive.
Mine certainly didn't suffer any problems, IIRC I stuck the clamp on the sprocket itself.

Andy1970 · « **Reply #11 on:** 05 December 2016, 12:14:21 pm »

I knew about the issue, but naively assumed that any Fazer still on the road would have had it fixed by now, i.e. the upgraded nut and if necessary a new shaft.

Anyway I'm in the process of restoring the bike, and had planned to have the engine out next winter anyway. So I'll drop the motor out and repair it properly with a new shaft.

Jules-C · « **Reply #12 on:** 05 December 2016, 02:41:05 pm »

I'm still on the original 9mm nut after 75k miles. If the shaft isn't undersize and nut torqued correctly, under or over tightening both bringing problems the original nut seems to hold ok and there are still a lot of them out there. But plan to swap it for the 12mm one next time the chain is replaced since the new nut only a fiver

fazersharp · « **Reply #13 on:** 05 December 2016, 03:53:17 pm »

Quote from: Jules-C on 05 December 2016, 02:41:05 pm

I'm still on the original 9mm nut after 75k miles. If the shaft isn't undersize and nut torqued correctly, under or over tightening both bringing problems the original nut seems to hold ok and there are still a lot of them out there. But plan to swap it for the 12mm one next time the chain is replaced since the new nut only a fiver

Yep thats because your bike is a 98

daviee · « **Reply #14 on:** 06 December 2016, 05:16:56 pm »

when i changed my chain and sprockets a couple of months ago i had to use a buzz gun to get it loose their was no way that was loosening off and with the locking washer i really dont see how they could come off i just put it back on with the buzz gun an flattened the lock washer i dont expect it to loosen off with it being torqued to 320 nm that is what the buzz gun claims anyway

Jules-C · « **Reply #15 on:** 06 December 2016, 05:56:44 pm »

It'll either stay on or fall off with stripped threads at 320nm

daviee · « **Reply #16 on:** 06 December 2016, 06:09:04 pm »

never stripped the threads you can tell by the sound of the buzz gun it changes tone once it hits the tightest point had to describe but its solid and with the locking washer i dont see it going any where

Graham53 · « **Reply #17 on:** 08 December 2016, 01:10:53 pm »

Many years ago I took my foxy to a well known tyre/servicing gaff in south London for new boots and chain and sprocks any way I picked the bike up and on the way home there was this ear defending screeching noise and I lost all drive , I shat me self cos I was doing 60 mph on the A12 and thought the gearbox was shagged.
Anyway on taking the side case off at the roadside it turns out it was the sprocket nut came off called the rac and got it home.
I went back to said well known tyre co and they were not helpful at all almost saying I was lying and offered me 10% off my next tyres for the inconvenience of putting my life in danger but at the time I didn't know about the nut issue and had fitted a new tab washer, torqued the nut and got back on the road and it lasted another 3years until I changed for the bigger nut.
I've never been back to said shop and I told them where to poke the 10%, should've sued em or something

Bretty · « **Reply #18 on:** 08 December 2016, 02:08:02 pm »

That's interesting. I took my bike to a (3 letter) south London tyre place for new chain and sprockets. I took the side cover off 4months later to find what appeared to elbe my original sprocket?! I guess they now have a policy of not touching the front sprocket on a fazer now?!

YamFazFan · « **Reply #19 on:** 08 December 2016, 05:07:45 pm »

Quote from: daviee on 06 December 2016, 05:16:56 pm

i dont expect it to loosen off with it being torqued to 320 nm

..........that IS a joke isn't it?!

daviee · « **Reply #20 on:** 08 December 2016, 08:11:40 pm »

nope i just buzzed it up till it stopped and the tone goes different the gun is rated to 320 nm so i guess its about their edit 325 bls/foot http://www.ebay.co.uk/itm/Sealey-Tools-CP2400-24V-1-2-Drive-Cordless-Impact-Wrench-Nut-Runner-Gun/191533177231?_trksid=p2045573.c100506.m3226&_trkparms=aid%3D555014%26algo%3DPL.DEFAULT%26ao%3D1%26asc%3D38661%26meid%3D48605c34f7a0430eb1225b82f468d338%26pid%3D100506%26rk%3D1%26rkt%3D1%26 this is the gun i used

YamFazFan · « **Reply #21 on:** 08 December 2016, 08:50:52 pm »

I'm amazed the threads could take that amount of torque.

320nm is MEGA tight

http://foc-u.co.uk/index.php/topic,14924.msg169224.html#msg169224

Bretty · « **Reply #22 on:** 08 December 2016, 10:25:36 pm »

Haha, not 320Nm.. 325ft lbs!!...
...which is only about 450Nm!!!
that can't be right, I don't think you could hang on to that.

why would you not use a torque wrench on this critical part with a known fault, that could result in a catastrophic failure?!

daviee · « **Reply #23 on:** 09 December 2016, 02:23:52 pm »

I have done this many times to different bikes and the last two being fazers never had a problem and deffo won't come off it took this gun to get the nut off as it was so tight I was lifting the bike off the ground with a break bar trying to get if off so it buzzed of no bother and buzzed back on till it stopped turning and the sound of the gun changes job done

slappy · « **Reply #24 on:** 09 December 2016, 02:48:27 pm »

If you ever sell your Fazer you better include the gun in the deal, pity the next owner who tries to undo that nut!