GS500 front sprocket almost killed me last night

[wera racer]

While commuting home from work last in 20 degree temps, the front sprocket on my 02 GS500 came off, knocking a hole in the case bottom and one in the case cover bottom, then jamming itself and the chain in the frame, abruptly locking up the rear at about 50mph. Very sporting as they say.

Can someone explain to me who was the Suzuki rocket scientist that decided a mere circlip was sufficient to retain a front sprocket? Unbelievable. My 78 GS1000 has a huge nut and one of those bent washer things to keep it from coming loose.

Had it happened a few minutes earlier on I-40 in heavy traffic, I would not be typing this or anything else...ever again.

Now it's a week or more to get a sprocket and clip from the factory as none of the online guys stock them.

I'm trying to get a sprocket overnighted from an eBayer and then find a circlip locally.

The bigger issue is I want a backup to the circlip and I'm even contemplating a few spot welds on the shaft.

If anyone has a better suggestion or either the sprocket or circlip for sale, please let me know.

I take responsibility for not checking it when I bought the bike used a couple months ago and I will cut a nice sized inspection hole in the case so I can give it a look every day.

Life is short enough without getting killed by stupid engineers.

Many thanks!
Rick

 

[Guest]

Wow! I'm glad to see you survived to type up this thread!

They must've changed the design after they went from the 450 to the 500 because my 450 is the same as your 1000 with the sprocket and lock washer that folds over the nut. No dodgy circlips here!

 

[BassCliff]

Hi,

I'm glad to see you posting this thread today! That must've been quite exhilarating!

You might want to check in the forum at www.gstwin.com to see if anyone there might know of a fix or upgrade. That sprocket setup certainly sounds inconvenient. Take care.



Thank you for your indulgence,

BassCliff

 

[Flaming Chainsaws]

Does anyone still want to swap the GS450 engine with a GS500?

Just kidding. Glad your OK. A mere circlip holding a death star spinning at incredible speeds... Damn you Suzuki...

My GS450 also has the giant nut with a folded tab.

 

[Flyboy]

I am glad it turned out ok, could have been nasty, I hear they have a special on underwear at Walmart this weekend.

Seriously, the circlip is not the problem, there is no sideways force on the clip, it will more than surfice, if it is in good condition and fitted correctly.
I would bet that the PO has used it more than once, probably taken it off and installed it with a two screw drivers, bent it open and out of shape in the process and that is why it came off.
Fit a new one, with a good set of circlip pliers, check that it sits snug and tight in it's groove, close up and forget about it.
I don't know the bike, but I am sure there should be a washer between the circlip and the sprocket, maybe check on one of the parts fische's.

Now go and buy that new underwear.

 

[GregT]

Kawasaki and some Hondas use a system which could be adapted.

A plate which fits over the spline then turns slightly to line up with 2 screw holes in the sprocket once it's in the groove. You'd have to hand make the plate as the splines are unlikely to be common but it is a positive location.

But yes, I agree if the rear end is in alignment there should be no load on the circlip.

rear end lockups are no fun - you can't save it by grabbing the clutch.

 

[mike-s]

it may seem a hack but a split pin perhaps?

 

[wera racer]

Thanks, guys. The gstwin site wasn't much help. You're probably right about the circlip being bad due to PO. An eBayer is sending me a new sprocket (old one had a lot of fore/aft slop, which probably would put some lateral pressure on the clip). I'm hoping to find a 22mm clip at a local HW store. I'm still going to do something else as insurance, even if it's hit the spline in two places 180 out with the welder. That and maybe cut an inspection hole in the cover to give it a regular check.

I vintage race a GS1000 and RD350, so this experience was good practice for a two-stroke seizure, albeit at a much higher speed.

Fortunately, it was 20 degrees so I was so puckered up there will be no need for fresh drawers.

Thanks, all!

 

[wera racer]

Well, I may not be as smart as a Suzuki engineer, but this may help ensure that the sprocket stays on if the circlip fails. It's appalling how shallow the groove on the shaft is. There's hardly any edge for the circlip to grab.

I welded a 6mm bolt shaft into the shallow hole on the end of the countershaft, then bolted up a piece of steel as shown. I will eventually use a slightly heftier piece, but this is what I had for now.