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Clutch /engine problem LC8

Posted: Tue Jan 09, 2018 9:50 pm
by P-vstrom
Hi, new to forum and KTM 990SMT. Just getting to love this bike ,have clocked up 3k miles in a couple of months,bike has only 6.5 k miles on it.
out one day and the chain guard on the swing arm got caught up in the front sprocket luckily only doing 30 mph at the time, back wheel locked,clutch casing pushed forward,damage to clutch shaft,also bearing in engine damaged.dont know if casing is damaged,no oil leack !. Mechanic thinks its a engine strip down as needle bearing shattered inside .Anyone experienced this. A chain & sprocket kit was fitted recently ,had a tight link,
don,t know if this was a reason for this problem.Any help appreciated.

Re: Clutch /engine problem LC8

Posted: Wed Jan 10, 2018 9:05 am
by jhalfhide
Crap. If chain and sprockets were done recently, was the manual followed with regards to chain slack? They run slacker than you’d think due to the suspension travel. If the fitter just went with what the norm is on other bikes, it could explain why it went tight.


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Re: Clutch /engine problem LC8

Posted: Wed Jan 10, 2018 9:20 pm
by P-vstrom
Thanks for reply jhalfhide, i thought the chain was a bit tight when i got it back from mechanic ,would it cause this problem ,i know the plastic
chain guard is riveted to the swing arm, can,t see how the tight chain would have made contact with it.front
sprocket locking bolt & washer looked ok. I will update further when i have more info, Thanks.

Re: Clutch /engine problem LC8

Posted: Thu Jan 11, 2018 7:41 am
by Gimlet
Do you mean the chain guard became detached from the swinging arm and was carried forwards on the chain and got rammed down between the front sprocket and the gearbox thus straining the drive shaft and wrecking the bearing?

If so that is something of a freak accident which I've never heard of before on an SMT or any other bike and chain tension would have had nothing to do with it (though as JH says, long travel suspension always requires a slacker chain than is usual on sports bikes or roadsters. In fact, ALL bike chains are better being a bit slack than a bit tight). The guard must just have come loose and you were supremely unlucky. The little chain guard screws do come loose on the SMT. It can be a buzzy bike when its on song - and most of the time it will be because that's the bike's character and you just can't help yourself. Its one of the reasons fibreglass huggers like Sidmarx can crack: the screws come loose and the hugger vibrates and fractures. In fact the Skidmarx isn't quite the right size and needs some additional spacers than the ones supplied to ensure the screws can be done up tight, but that's another story..

If a stuff-up between chain guard and gearbox is what's happened to you then yes, you do need a strip down to fix the gearbox bearings. Don't know who top suggest where you live. There's a great little independent KTM specialist near me who know the LC8 990's inside out and charge about half what KTM main dealers do but its an awful long way from you in Ireland. Hope you get it sorted.
Get some threadlock and keep an eye on all fasteners.

Re: Clutch /engine problem LC8

Posted: Fri Jan 12, 2018 2:05 pm
by Magic Wand
'P-vstrom'
Welcome to the forum!

As I understand it, the swing arm chain protection unit (the chain slider) came loose and the drive chain drag it into the front sprocket area, damaging also the front sprocket cover. Am I right?

You have got the answer what to do from 'Gimlet'.

Good luck!
/M

Re: Clutch /engine problem LC8

Posted: Sun Jan 14, 2018 8:27 pm
by Nordic09
Without seeing any pictures etc.. just as an idea of potential warranty case: maybe they did put the chain as too tight in service, and too tight chain bended the drive shaft / bearing damage and started the unlucky event. Chain should really be quite loose at the right setting.