Front sprocket grinding swinging arm?

Hi guys

Need a bit of advice from the experts.. I have only had this bike for 3 weeks so I'm unsure, but based on my knowledge of previous bikes I have owned this just looks wrong.

The front sprocket appears to have ground a groove through the rubber and into the swing arm.. I'm unsure...

Apologies for the pic, best I could get. Is my frame bent?

How big is that sprocket? Stock should be 17 tooth on 05/06 bikes and 16 tooth on anything after that.

And how big is rear sprocket? Stock is 38.

I counted 17 on the front.. And the part number one the sprocket ends in .017.. I haven't counted the rear and I don't have access to the bike atm.

Difficult to read on my phone but part number stamped on sprocket doesn't look like the right one - could be wrong, larger diameter 17t sprocket - but then the chain pitch must be also be wrong?

Can't be bent frame though 'cos sprocket/swinging arm dumb/alignment is set by engine casing - must be wrong diameter sprocket surely.

I will have a look at mine tomorrow for you mate. There's something wrong there if the sprocket is hitting the swingarm. I'll take a photo of my bike and post up. Is that glittering stuff aluminium bits? Off the swingarm?

A worn swing arm bearing could cause this. When you have the bike back see if you can move the arm side to side.

I've had a look and the part number on the fiche matches the part number on the sprocket, so i guess it's right..

No movement in the swinging arm that we can tell but the swinging arm is now bent - basically my chain came off yesterday and locked the back wheel up and chucked me down the road at 25-30 mph under acceleration, the back wheel then hit a curb and has shattered the back wheel and bent the swing arm.. i'm going to be taking this up as a mechanical failure and try and get the bike put right that way.. obviously if this isn't how it should look and the swinging arm has been eaten away by the sprocket then i simply won't want this bike back, just wouldn't trust it again, i'd want my money back and would go elsewhere for a different duke..

damage using new parts would make the bike an economical write off it i went through insurers, but i've only had the bike 3 weeks, bought from a KTM dealer and it's still under it's 3 month warranty..

If anyone can get my a photograph of their front sprocket / swing arm from the same angle as above, preferable from a 2005 duke but i believe they are the same in this area anyway except from the sprocket size (it's the swing arm that i'm more interested in) that would be great.

Cheers

rip

Man if you bought the bike in this condition from a KTM dealer, he's reponsible for your troubles...
The front sprocket shouldn't be hitting the swingarm...

Just to give a little bit of urgency as to why i'm asking these questions...

this is the aftermath of what I believe to be a chain failure - me and bike sliding down the road - bike hitting a kerb without having much of the speed scrubbed off by the slide along the road. so i'd say the rim hit the kerb at about 25-30mph, it and the swing arm have taken a lot of damage, rim shattered on impact and the swing arm is twisted.

The chain is missing half of a link which I think is what lead to the rear wheel lock up.. couldn't find the missing link at the scene of the drop but i guess that could have flown off anywhere...



As you can understand i'm pretty upset / pissed off about it..

EDIT: - the white boxes are just covering up identifying marks.. i want you guys' opinion, but don't want it to affect any potential legal battle.

What a shitter. Something seriously wrong would seem to have caused that - did the side plate come off the chain's soft link? If so then, the chain clearly wasn't installed properly.
How many miles on the bike? Is it the original chain?
Hope you're OK.

I didn't touch the bike after it being recovered other than taking the front sprocket cover off for a cursory look.. The bike has 8700 miles on the clock.. 8500 of them by a previous owner who I doubt ever rode with any real 'spirit'. There is no reference in the service history (which is extensive) of it ever having a new chain or sprockets fitted.

I am a bit sore.. My gear did it's job, my knee took a knock and has some fluid behind it, some ligament damage in my groin, some neck ache has developed today... i was very lucky

From the first picture it is hard to see if there was any interference between the sprocket and the swing arm. If this were after the incident, There is little telling a cause. You mention the word spirited in relationship to the previous owner. Or should I say the lack thereof. I have witnessed rear wheel lockup on a few occasions when downshifting without a blip and or from a touch too much rear brake allong with a spirited downshift. Were you decelerating when the lockup occurred?
I have gotten all out of shape with spirited downshifts and on a VTR1000 it was an even nastier situation as the flywheel weight on the Honda made it less forgiving. I cannot at all see how a sprocket grinding into a swingarm connection could have gone unnoticed for this long. With little to go by and at the risk of sounding rash in judgement, I find nothing pointing any further away from rider error.

I would totally agree with you regarding wobbly downshifts.. I had similar experiences with my sv650.. However on this occasion I was accelerating.. I only mentioned spirited riding in the context of expected chain wear.. On this occasion the riding was relatively sensible (close to town centre - has a nearby population of elderly / retirement homes)

EDIT: I do appreciate the alternative point of view.. Tbh any answer is better than what I know now.. I have no idea why the rear locked up.. There are many reasons it could have... I am currently just speculating - I am no mechanical expert especially with superdukes.

Check to see if all rear sprocket bolts are tight. This has been a place where the oblong washer-nut has interfered with the swing arm.
My bet is the chain is original as they are quality and should more than last 8700 miles. Therefore it will be continuous and not be aftermarket link failure. Brake? does the wheel, or what is left of it spin freely?
I certainly hope the dealer does not give you any problems. Maybe this was Jim H's bike and he boobietrapped it

My 1290 is exactly the same, there is a grove cut out of the swing arm to allow the sprocket to turn as it is so close to the swing arm, seems like a poor design that the clearance is so close, but that is nothing new as I an starting to find with KTM in general.

Not quite as bad as that one, but I am guessing it is not going to take much wear in the swing arm bearings, before it touches

was the sprocket actually touching the swing arm?
i was looking at some pics of my 990 when i replaced the sprockets and there is a groove cast into the swing arm but it doesnt actually touch.
i was installing a 16 tooth KTM sprocket, looks like there was about .125" clearance.
its hard to tell from your photo because you have a lot of grease built up.
it should be easy enough to tell, degrease around the sprocket area, if their was contact it should be all abraded there. and id think any metal shavings would be suspended in the grease.

Looking at the heel-plates, that's a 06/07 model bike which would have come with a 17t front sprocket as standard.

I know mine was tight to the swinging arm but it was replaced with a 16t many years ago, and subsequently replaced with a 16t even though the aftermarket kit did come with a 17t originally. I did fit the old 17t back on for a trip to the Isle of Man and seem to remember it was difficult to get it back on with the build up of chain lube etc so not surprised it looks close but again, shouldn't touch.

The missing split link looks like it was knocked off as the rear of the bike hit the curb, plus it doesn't look like the soft link either and as said above, 8700miles on standard chain is acheivable with little wear.

The rear exhaust looks very clean, has the motor been out for work recently?

eta - just spotted your wanted ad, why are you asking for a swinging arm spindle - has this bent due to the accident (now causing the sprocket clearance issue?). I'm thinking the clearance issue is as a result of the accident, not the cause - sorry.