Front Sprocket Came Off - Low Sided! Circlip Question

[Meuryn]

Hi everyone,

So I crashed for the first time after three years of riding on Saturday. Thankfully minimal damage to the bike (busted bar end mirror, snapped brake lever, and a bit of scuffing on the exhaust). I got away with just a sprained ankle. Started with a big bang as I went into a corner and before I know it the rear wheel is locked and the bike and I are sliding in tandem down the road 

It looks like the front sprocket came clean off the drive shaft (if that's its proper name), locking the rear wheel, even though the circlip was on the last time I checked (I can only guess that it corroded and split off). I'm looking for a replacement circlip; I think I need a 22mm clip, would this work? http://www.ebay.co.uk/itm/NEW-External-circlip-c-clip-circlips-6mm-to-30mm-U-choose-size-quantity-DIN471-/121024799084?pt=UK_DIY_Material_Nails_Fixing_MJ&var=&hash=item1c2da3e16c

The bike is currently in the shop as the sprocket ended up lodged between two spars in the frame just south of where it would usually sit. I'm guessing I'll need a new chain (it looked pretty mangled) and a new sprocket, which thankfully I already have.

Any idea how I can avoid this happening again?

Cheers,
Meuryn

[burning1]

There are one or two things that might help:

* Safety wire the clip through the eye-holes to help prevent it from coming lose.
* Replace the clip every time you change the sprockets.
* Coat the clip in grease to help protect it against weather.
* Inspect the clip every time you change the oil.

[The Buddha]

That circlip on the counter shaft is a stupid design. I've seen many cases of where that clip flies off, or breaks off and the sproket and countershaft are boogered up.
I'd look into drilling the center of the shaft and tapping it and installing a bolt and a washer holding the sproket in.
Cool.
Srinath.

[Atesz792]

Does every model year use this design to secure the sprocket in place?

[The Buddha]

It is the same dumb design on all GS'es. No other bike afaik has it. Worse yet, I dont even think the GS450 was that way.
Cool.
Buddha.

[Big Rich]

It is the same dumb design on all GS'es. No other bike afaik has it. Worse yet, I dont even think the GS450 was that way.
Cool.
Buddha.

Correct. The GS450 (and GR650) use a threaded output shaft with a nut on the end, and a bent / locking washer to make sure the nut stays tight.

[yamahonkawazuki]

Had a gr650.a gripe to find parts for in theus lol. 

[gsJack]

I have 100k miles on the original circlip on my 02 GS and it's never come off or shown any signs of rust.  On my 1st GS a 97 I butchered the original circlip on the first sprocket change and replaced it using the special pliers I'd bought and have used since.  It went to 80k miles w/o further problems when bike was totaled and replaced.

I don't believe this design is the best but I also don't believe the sprocket would ever come off if the rear wheel was aligned at least close to straight ahead, the axle nut was properly tightened, and the chain slack was at least close to where it belongs.

At the 2nd chain replacement on the 97 I bought a DID chain and a Socket Specialist 15T front sprocket and it didn't have the hub on it like the sprockets used after 93 on GSs.  I contacted SS and they said it wasn't needed since the sprocket followed the chain guided by the rear sprocket and sure enough the sprocket was right there next to the circlip and the extra space was always behind it.

I think Suzuki must have had a reason to try this design, a little compliance of the sprocket could be beneficial to a misaligned chain.  Perhaps it was just because it was cheaper to cut the circlip groove while machining the tranny output shaft than it was to drill and tap the end of the shaft.     Anyway I don't have a problem with it.

[The Buddha]

I've also run it on my bikes. Maybe not 100K on 1, but run 100K on 17 GS'es. Bad designs dont show up under the ideal conditions. You start getting close to the boundary and you see things fail. The circlip was a bean counter decision. Much like the motor that doesn't seal up well @ the rings, or the frame that rusts @ every weld and has weld zits all over the place.
Its easy for a bean counter to say, you should keep it in perfectr alignment, have it stored inside and never ride in the rain and it will be perfect. We wont be spending the extra 20 mins on the bike to make everything last longer and work better.

Cool.
Buddha.

[yamahonkawazuki]

Aint that the truth

[gsJack]

For your information Srinath I've ridden my 02 GS year around in temps from 20F to 100F and I've probably ridden in the rain more miles than you've ridden any or all of your bikes down there in the sunny south.

What the hell does 100 miles on 17 GSs prove when were talking about how something like a circlip will hold up in the long run. 100k miles on one bike with the same circlip and numerous sprocket changes is significant input I think, I'm not bragging about the 100k miles buddy just stating the facts and they are facts. 

My bike is rarely in perfect alignment but it's always close enough to be a good ride and my chain gets a bit slack at times but gets corrected when it gets convenient to do so.  Have you ever pulled a front sprocket off with the chain in proper adjustment without backing off the adjustment, it takes a good pull to do so. 

In my opinion something went wrong on the bike above to cause the sprocket to come off, a buggered up circlip, a too loose chain, a badly out of line wheel, a bad wheel bearing lockup, etc.  How often have we heard of a front sprocket coming off, I can't recall any off hand.

[HPP8140]

I have over 100k on 3 GS500s with the stock clip.

[bombsquad83]

For your information Srinath I've ridden my 02 GS year around in temps from 20F to 100F and I've probably ridden in the rain more miles than you've ridden any or all of your bikes down there in the sunny south.

What the hell does 100 miles on 17 GSs prove when were talking about how something like a circlip will hold up in the long run. 100k miles on one bike with the same circlip and numerous sprocket changes is significant input I think, I'm not bragging about the 100k miles buddy just stating the facts and they are facts. 

My bike is rarely in perfect alignment but it's always close enough to be a good ride and my chain gets a bit slack at times but gets corrected when it gets convenient to do so.  Have you ever pulled a front sprocket off with the chain in proper adjustment without backing off the adjustment, it takes a good pull to do so. 

In my opinion something went wrong on the bike above to cause the sprocket to come off, a buggered up circlip, a too loose chain, a badly out of line wheel, a bad wheel bearing lockup, etc.  How often have we heard of a front sprocket coming off, I can't recall any off hand.

I agree.  I think the point here is that the OP needs to check the things that gsJack mentioned to make sure he doesn't face another failure in the future (of the same kind or different).

Certainly there is always a better (read more expensive) way to build a bike.  The GS was built to a price point.  There is little point to arguing about how it should have been designed, especially when most of the time we are talking about bikes that were bought for <$5k new or for as little as <$1k used!

EDIT: Not to mention that the humble GS had an over 20 year production run largely unchanged.  If there would have been a major issue in the engineering, we would have heard about it.

[Meuryn]

Hi everyone,

Thanks for the replies! The wheel / chain were aligned by the bike shop after fitting a new rear tyre about a month before, and I had no handling symptoms to suggest they cocked it up, so I don't think that contributed to the sprocket flying off. Both sprockets and the chain were in good condition too 

I ordered a 22mm circlip as reccomended by this thread - http://gstwins.com/gsboard/index.php?topic=52140.0 , and, lo and behold, it's far too small. Even with circlip pliers there was no way I was getting it on. Could anyone link me an ebay listing for a circlip they know would fit? Or even just the correct dimensions (internal or external diameter) so I can get back on the road? I would buy an OEM replacement but no online or local dealers have anything appropriate in stock 

Thanks again for the all the advice!

Meuryn

[gsJack]

From GS UK site:

Part number is 08331-3125A - 25mm * 1.2 mm

From JT: