Serious Safety Issue on a 2009 Monster 696

[mikesmithmjs]

What is chain freeplay, with & w/o rider?

I made this simple gauge to keep with the bike and use it to check tension. The chain pins measure directly in the center of the line when placed on the flat part of the swing arm.  I have never checked when sitting on the bike.

[battlecry]

The homemade gauge is a good idea, Mike.  It seems like you are mainly measuring the drop.  What is the distance when you push up on the chain?  

[mikesmithmjs]

The homemade gauge is a good idea, Mike.  It seems like you are mainly measuring the drop.  What is the distance when you push up on the chain?  

i cant say because i never measured while pushing up.

[battlecry]

Mike, on the older swingarms the chain slack spec is measured as the difference between the drop (What you are measuring) and the rise (pushing up).

I'm not familiar with your swingarm, but I think one measurement may not be sufficient to determine your chain slack.  Your gauge can help you see if the chain is stretching over time, but I'm not sure it helps you see if it is too tight.  I gather the bike is at the shop, so you can't take a measurement, right? 

[mikesmithmjs]

  I gather the bike is at the shop, so you can't take a measurement, right? 

Right.  I was just following how the manual says to measure the tension.  btw, i've never adjusted it as it always was in the 47mm range.

[battlecry]

If that is the way the manual says to measure it, that's good.  Note that if you only take the drop measurement, that may mean something different if you go to a much larger or smaller rear sprocket (conditions probably not addressed in the manual).  So a more general method (difference between rise and drop) that allows you to measure chain slack in different conditions is a good tool to have.  Then if you calibrate that measurement method to the one you use, measuring only the drop, that may be satisfactory and a time saver too, another good tool.   Since your sprockets are stock, this may just be an academic concern and I'm sure your dealer will look at the chain slack as part of his inspection.

[Coffeebaron]

Hey all, I know this is an old post, but I would just like to say how glad I am these things are still online! I've just gotten back from my weekley food shop on the M796 I own to discover the exact same issue as the original poster! javascript:void(0);

I noticed the shine of bare metal where the chain had sawn away at the swinging arm, and upon investigating the countershaft sprocket on a hunch, discovered it had been pushed all the way back to the engine block, the chain was alarmingly tight, so I slackened it off which practically caused the sprocket to fall off.

For what it's worth, my 796 is 2011 reg, and again has only been touched by the duc dealer I bought it from (this one was an 1100 mile ex demo) and is still under warrenty.

I personally agree with the original poster, it is a serious safety issue, or more precisely a potential one, as should the swing arm be sawn through, or the countershaft sprocket jolt loose, the chain would be free to wreak havoc.

I'm hoping the dealer will be gracious about sorting out the repairs under warrenty, and supply a courtesy bike in the mean time.

Interestingly though, my countershaft was in the exact same condition as the OP's- rusty appearance and dry, whereas the chain and rear sprocket lubed and in good condition.

[rockaduc]

Hey all, I know this is an old post, but I would just like to say how glad I am these things are still online! I've just gotten back from my weekley food shop on the M796 I own to discover the exact same issue as the original poster! javascript:void(0);

I noticed the shine of bare metal where the chain had sawn away at the swinging arm, and upon investigating the countershaft sprocket on a hunch, discovered it had been pushed all the way back to the engine block, the chain was alarmingly tight, so I slackened it off which practically caused the sprocket to fall off.

For what it's worth, my 796 is 2011 reg, and again has only been touched by the duc dealer I bought it from (this one was an 1100 mile ex demo) and is still under warrenty.

I personally agree with the original poster, it is a serious safety issue, or more precisely a potential one, as should the swing arm be sawn through, or the countershaft sprocket jolt loose, the chain would be free to wreak havoc.

I'm hoping the dealer will be gracious about sorting out the repairs under warrenty, and supply a courtesy bike in the mean time.

Interestingly though, my countershaft was in the exact same condition as the OP's- rusty appearance and dry, whereas the chain and rear sprocket lubed and in good condition.

you know the rules...pics or it didn't happen

[Coffeebaron]

Proof enough javascript:void(0);

[kyle]

Yeah.. that's pretty much not cool..
And I agree on your wording of the issue.

While there has been no serious safety issue to yourself or the OP in this case, there is a fair potential to seriously harm someone.

If it's still in warranty as you say then your dealer will look after you. If not, consult another dealer.

[BastrdHK]

I really do not understand how this could happen.  We have a case here with two similar bikes/issues.  My M900 uses the same, and I have serviced a number of older monsters with the same system, including changing sprockets and chains and have never seen this issue.  I have nearly 30k on my original plate and it is slightly worn as  you would expect from performing its duty.  No where near failure though, to the point that I have written it off as something I will not have to replace for the life of the bike.

I have broken teeth on rear and front sprockets, and ridden too long with a worn, stiff linked chain in my naive/tightwad days. So I feel qualified in saying I have tested the system and its performed very well.

Getting back to the problem, I am convinced it is a chain tension or wheel spacing/alignment issue.  Since the sprockets are being pulled inward, that would indicate the wheel alignment or spacing is putting stress on the chain to move inward.  Since the retaining plate is the weak link, it gives first.  If it is rear wheel spacing/alignment, we should see more wear on the inside of the rear sprocket.

Can you guys check your rear sprockets and take pictures?

What was the final story on the OPs bike?

[cyberswine]

This second incident is on a 796 though, single swing arm.  Hard to have an alignment issue, and chain tension measurement is simple and very specific.  (That bit's been flogged to death in many other threads.) 
I know what I'm going to check on mine tomorrow for sure.

[Coffeebaron]

As cyberswine said, sssa the wheel alignment is not an issue, and I followed the adjustment advice of the duc mechanic at the dealers of making sure the chain was slightly on the slack side of things- although I've only adjusted it once in the 5k I've ridden it.

@ BastrdHk i'll try and get some pics if I can, but the bike is now at the dealers being worked on- incidentally Ducati Card Assistance were excellent with their speed in collecting my bike and ferrying us bothe to the dealer.

I'm going to post the outcome of this and what findings there are once I hear back from the mechanics/Ducati. I'm glad for the warranty.

[Speeddog]

A few ST2's had this issue, and I've seen it on one other Duc, but can't remember which right now.

I suspect it's a problem with a lack of adequate hardness of the output shaft.

When the retainer plate wears through, sometimes the sprocket goes inboard, sometimes outboard.
I've not puzzled out why it varies.

[Curmudgeon]

I'm going to post the outcome of this and what findings there are once I hear back from the mechanics/Ducati. I'm glad for the warranty.

Please do and hopefully they find an actual cause. I've had bikes with this setup for eons without anything like this weirdness. No indication of this on my 796 but no desire to start now! What was the production date of yours? Mine was 06/2011.