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Discussion Starter #1
Do you all notice chain slapping intermittently when riding in 1st or 2nd gear. Not a continuous hit but each time throttle is turn and chain has to engage. I noticed when I rode without my helmet otherwise I don't notice as much. Chain tension at 3mm
 

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I have the same issue. Unfortunately its a double edged sword. Loose chain causes chain slapping, tight chain causes leaking countersprocket seal.

I've chosen to run my chain in the loose side to avoid the oil leak.
 

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Discussion Starter #3
I have the same issue. Unfortunately its a double edged sword. Loose chain causes chain slapping, tight chain causes leaking countersprocket seal.

I've chosen to run my chain in the loose side to avoid the oil leak.
So at least I'm not alone. Thanks for responding and helping get this off my mind
 

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Our swingarm length and geometry means we need our chain a bit looser than a traditional sportbike chain. So for all of the times when the sprockets and swingarm pivot aren't in a line, our chain can touch the swingarm guard and front cover.
 

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I attempted to find the sweet spot with chain tension numerous times on this bike. Never had a bike that's so damn quirky when it comes to chain adjustment! Loose enough to avoid excess strain on the countershaft does result in a little slapping, along with added jerkiness at low revs for good measure. I guess you'd call it "normal", if a little irritating!
 

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I attempted to find the sweet spot with chain tension numerous times on this bike. Never had a bike that's so damn quirky when it comes to chain adjustment! Loose enough to avoid excess strain on the countershaft does result in a little slapping, along with added jerkiness at low revs for good measure. I guess you'd call it "normal", if a little irritating!
My 1090R w/ ~9 inches of rear suspension travel is even worse in that respect...you just learn to ignore it I suppose. I barely notice it on the Duke.
 

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Discussion Starter #7
Our swingarm length and geometry means we need our chain a bit looser than a traditional sportbike chain. So for all of the times when the sprockets and swingarm pivot aren't in a line, our chain can touch the swingarm guard and front cover.
Thank you for your explanation and input.
 

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Discussion Starter #8
I attempted to find the sweet spot with chain tension numerous times on this bike. Never had a bike that's so damn quirky when it comes to chain adjustment! Loose enough to avoid excess strain on the countershaft does result in a little slapping, along with added jerkiness at low revs for good measure. I guess you'd call it "normal", if a little irritating!
Okay, so I'm understanding this better and better. Thank you
 

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I dispute the theory that a tight chain would cause the c/s seal to leak. Are we talking within spec. as per manual here?

I think its caused by vibration and Ive notice when wheeling the bike a louder than usual clicking, (never did it when new), and I honesty think the chain is el-cheapo CZ crap that has stretched.
Get a decent DID and go feom there I say.
 

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I dispute the theory that a tight chain would cause the c/s seal to leak. Are we talking within spec. as per manual here?

I think its caused by vibration and Ive notice when wheeling the bike a louder than usual clicking, (never did it when new), and I honesty think the chain is el-cheapo CZ crap that has stretched.
Get a decent DID and go feom there I say.
You mean a tight chain that pulls the countershaft off-axis in the bearing and seal won't cause an issue ever? Before I put a 15T in a certain someone's 890 I checked the adjustment and got 8mm gap. I had him hop on the bike to see how it sat loaded and the chain was a guitar string, we were both shocked that he didn't bind up the rear on our rides. He was not on the original CSS.
 

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My KTM mech told me outright to leave the chain looser than you'd think. One of these days I'll do some axial measuring. If a tight chain can provoke steel chain links to crack - it'll pull a bearing off axis in two shakes of a lamb's tail.
 

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Yeah Nah, can keep your loose chains.
I've seen how reliable a tight one within spec can be first hand.

Seals are cheap, titanium body parts are not.
 

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Yeah Nah, can keep your loose chains.
I've seen how reliable a tight one within spec can be first hand.

Seals are cheap, titanium body parts are not.
Pretty extreme example of a loose chain. :D

Cant say I’ve ever seen one like that.
 

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You mean a tight chain that pulls the countershaft off-axis in the bearing and seal won't cause an issue ever? Before I put a 15T in a certain someone's 890 I checked the adjustment and got 8mm gap. I had him hop on the bike to see how it sat loaded and the chain was a guitar string, we were both shocked that he didn't bind up the rear on our rides. He was not on the original CSS.
If you had an 8mm gap, thats 3mm tighter than max tightness.
A 'loose' chain on these bikes will probably be touching the swingarm.
 

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If you had an 8mm gap, thats 3mm tighter than max tightness.
A 'loose' chain on these bikes will probably be touching the swingarm.
Correct on both counts! Mine would get super slappy at the 2mm gap mark, and distractingly jerky, when I still had my stretchy stock chain.

I raised my 790 +6mm front and +14mm rear to try and emulate the 890's geometry (+15mm height at the seat, same swingarm part #). My usual target 4mm chain gap became 3mm. I wasn't sure if it would make a noticeable difference to the chain, but it did. :)
 

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I have the same issue. Unfortunately its a double edged sword. Loose chain causes chain slapping, tight chain causes leaking countersprocket seal.

I've chosen to run my chain in the loose side to avoid the oil leak.
I have very good mechanic who has worked on Guzzi and KTMs for years. I agree with him that the bike owner’s manual method (both 2018 and 2019 versions) is unnecessary and doesn’t take into account rider weight which can vary from say 45 kg for a smallish lady up to over 100 kg for a solid bloke. Just do it the age old way of having someone measure the bottom row slack when you’re on the bike. I always use 30 mm though l had a Yamaha once that specified 50 mm. Cheers
 

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I have very good mechanic who has worked on Guzzi and KTMs for years. I agree with him that the bike owner’s manual method (both 2018 and 2019 versions) is unnecessary and doesn’t take into account rider weight which can vary from say 45 kg for a smallish lady up to over 100 kg for a solid bloke. Just do it the age old way of having someone measure the bottom row slack when you’re on the bike. I always use 30 mm though l had a Yamaha once that specified 50 mm. Cheers
The 790 chain tension seems particularly sensitive to load variations over the first part of its travel. I haven't done any precise measuring to confirm this but when I was on tour in February, we discovered that my chain was really tight. I was carrying extra luggage load but not by any means a massive amount. I checked the tension before leaving on the tour although not with all the luggage on. Perhaps I should have added some precautionary preload. I always used around 30 mm on past bikes. I'll do some experiments with neighbours of varying weights :D
5110
 

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@magoo’s mechanic is right, I’ve been adjusting my dirt bikes chains and now my Raptor with me sitting on it. Not so easy to do alone with the duke, so I was able to find the sweet spot after a few try witch is like(I don’t really mesure anymore) the looser of the suggested specs for my 195lbs. I still have the crapy CZ chain on it, it needed often adjustments at the beginning now it doesn’t seems to be stretching as much at close to 8000 km but it started squeaking a few weeks ago and lube would stop it to the first stop now !!! So i shall loose patience shortly and put a better DID on.
 
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