ZX10 front sprocket came off at speed

ZX10 front sprocket came off at speed

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Discussion

sideways500

Original Poster:

92 posts

263 months

Thursday 24th April 2003
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Hi everybody. I've been pistonheading for a bit, but only cars up 'til now. Appologies if this topic has come up before.

My ZX10 wasn't getting a lot of use and I was contemplating selling, then I threw it down the M5. The evidence suggests that the front sprocket parted company with the bike, straight through the casing, at approx. 70mph. The chain wrapped around the back wheel and locked. I'm pretty much intact; bike has peg, lever and fairing damage on left side.

I'm curious to know if anyone has had this happen before? I seem to remember hearing that it was a weak point with the ZX10, and I checked it regularly, for the first 1000 miles, the last time I changed chain and sprockets.

Thanks.

victormeldrew

8,293 posts

284 months

Thursday 24th April 2003
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Ouch!

had something similar when gearbox seized in a KMX125 flat out - your first reaction is to dip the clutch and boy is it a shock when it makes no difference! ZX10 is a bit more substantial though, glad you survived the experience.

Mon Ami Mate

6,589 posts

275 months

Thursday 24th April 2003
quotequote all
First off, I'm pleased to hear that you escaped unscathed. A sudden failure at speed has to be my worst motorcycling nightmare.

I have owned lots of big Kawasaki's - dating back to a 750 Turbo and including two zx-10s and four zzr1100's. I covered more than 70,000 miles on one ZX10, without any mishaps at all.

I must admit I've never come across this issue before on the ZX10 - although I remember something similar with early ZXR750s, that demanded a factory recall. How many miles has the bike covered and do you have a service history? Is the wreckage complete enough to pinpoint the cause of the failure?

It may be a one-off, and you may just be very unfortunate, but it seems strange that, at the very least, another Kawasaki from the same period had a similar issue.

sideways500

Original Poster:

92 posts

263 months

Thursday 24th April 2003
quotequote all
Thanks for the replies.

MAM - The bike has done approx 65,000 miles (28,000 in my care) and I have done all the servicing myself. Only bigger jobs went to garages.

Looking at the bike, the sprocket cover is blown apart and the chain is still in one piece, around the rear wheels and swing-arm pivot. I don't see any other way it could have happened.

Maybe this is the tip of a great Kwacker manufacturing cover up? Or not.

Mon Ami Mate

6,589 posts

275 months

Thursday 24th April 2003
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Are the sprocket and the output shaft still in one piece?

sideways500

Original Poster:

92 posts

263 months

Thursday 24th April 2003
quotequote all
Output shaft in one piece with thread "bruising". Bizarrely I seem to remember having the front sprocket at the hospital, but can’t find it now.

Mon Ami Mate

6,589 posts

275 months

Thursday 24th April 2003
quotequote all
Can you remember if it was in one piece or fractured?

sideways500

Original Poster:

92 posts

263 months

Thursday 24th April 2003
quotequote all
I think it was in one piece.

cazzo

14,851 posts

274 months

Thursday 24th April 2003
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Don't know if it's a similar cause but the front sprocket on my 916 came loose - basically the 2 bolts fell out and retaining plate dropped off, the 'chew' marks on the cover show that the bolts had been scraping the cover for a while before finally falling out & leaving the plastic cover as the only thing holding the sprocket on. Although I don't think the chain would let it slide far enough to come off the shaft unless it was slacker.

No idea how long it was like it but found it while doing another job - often wonder what might have happened if it had come off though! Now I check it often and have put plenty of Loctite on the screws!

Have had Kawasaki's before and never had any problem like this nor do I know of any mates with Kawasakis having the problem.

I have had high speed lockup before however was the engine and clutcing in stopped it but was still scary though - Glad to hear you didn't get too badly hurt.

Ballistic Banana

14,700 posts

274 months

Thursday 24th April 2003
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Never heard of that happening before,then again i dont know anyone with that make of bike.

glad you are OK though

BB

Mon Ami Mate

6,589 posts

275 months

Thursday 24th April 2003
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sideways500 said: I think it was in one piece.


I know one of the technical training managers at Kawasaki's Bourne End HQ (essentially his job is to train mechanics to service Kawasaki bikes, ATVs and jet skis). I'll mention this to him and see what he says.

This isn't intended as an insult, and please don't take it as such, but bearing in mind that the major components were complete, are you sure that this couldn't have been caused by an overly loose chain?

Ballistic Banana

14,700 posts

274 months

Thursday 24th April 2003
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Mon Ami Mate said:

sideways500 said: I think it was in one piece.


I know one of the technical training managers at Kawasaki's Bourne End HQ (essentially his job is to train mechanics to service Kawasaki bikes, ATVs and jet skis). I'll mention this to him and see what he says.

This isn't intended as an insult, and please don't take it as such, but bearing in mind that the major components were complete, are you sure that this couldn't have been caused by an overly loose chain?


Would a broken chain rip the sprocket off and send it through the caseing?? frightening if it could and i dont know thats why i am asking

BB

Mon Ami Mate

6,589 posts

275 months

Thursday 24th April 2003
quotequote all
Sideways, have a look at <www.zx1112.bigbikeworld.com/forum/> - you'll find a massive amount of know how on big ZXs in residence.

I've seen the after effects of a chain jumping the sprocket before - and it isn't pretty. A flailing chain with that amount of torque going through it is bound to cause considerable damage. It will easily destroy the crankcases and will also take your leg off if you are unfortunate enough to be in the way.

I'm not suggesting that this is what took place, but I'd want to be pretty certain it was a component failure before banging on Kawasaki's door.

RUF 3

240 posts

274 months

Thursday 24th April 2003
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Whilst you have my sympathies - I came off a Bimota at over 100mph when the gearbox seized - I honestly cannot imagine Kawasaki having much interest in what happens to a (probably) 10+ year old bike which has 65000 mls on it, and has been maintained by an unqualified home mechanic.

hertsbiker

6,371 posts

278 months

Thursday 24th April 2003
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sorry to hear this mate, but I heard that the tab washer on the lock nut on Kwackers are subject to failure if not bent over correctly... whatever that mean I'm not sure, but gearbox pinions coming loose HAS BEEN HEARD OFF BEFORE.

Glad you're ok.

C

sideways500

Original Poster:

92 posts

263 months

Friday 25th April 2003
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Firstly, thanks for the continuing response.
Secondly, I need to learn how to quote people.

MAM - I checked and adjusted the chain two days before, so don't think that was it. Unless there was a loose spot that I missed? Not 100% sure.

BB - Chain is still in one piece. The sprocket came off by itself, then "exited stage left" through the casing.

hertsbiker - I checked and secured the "bent tab washer" when I put the whole thing on. Then checked weekly for the next few months. Not in the last six months, sadly.

Everybody else - Thanks for the concern. I agree that there's not much mileage in the litigation route. Although I am a reasonably well qualified mechanical engineer, that's not the same as a franchised dealer receipt.

If it turns out that the same thing has happened to many other ZX owners, I'll pursue this further. For now however, a suggestion to remove the front sprocket cover from time to time and inspect. Just to be sure.


pawsmcgraw

957 posts

265 months

Saturday 26th April 2003
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a good friend of mine owns a Kawasaki dealership and has raced them for years.Soon as i forward this email he knew instantly all about it.He says its a common problem and its also on zzr11's.He states its because the sprockets have to be mega tight or they come loose.Its on the cover of one of the workshop manuals.The problem is to gain the extreme tightness people use rattle guns and even set at max pressure this is not enough.Its shown in the manual that it has to be done with a 3ft extension lever gradualy with someone on the bike and the rear brake locked.Also,because of the length of the shaft the design of the sprocket if it comes only slightly loose it chucks the chain off.The locking washer/tab doesnt stand a chance!He knows of loads of cases of this and since about 97 has followed this routine for fitting them....no cases of it through his dealership since.He says all Kawasaki dealerships should/are aware of this as it was a regular topic of conversation.Hope this helps,and he did say if anyone needs any information about this subject he would gladly pass on all knows.