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Discussion Starter · #1 ·
I recently noticed a strange behavior on my '14 ST3R with roughly 5k miles on it:

On deceleration to a stop with the clutch lever pulled in, I noticed that a vibration could be felt through the handlebars and seat beginning at 21 mph, most noticeable at 20 mph, and going away below 19 mph. I adjusted the clutch play, which had no effect. The symptom is less noticeable when on the brakes as I decelerate past 20 mph (again with the clutch lever pulled in), though brakes could dampen the vibration and also reduces the time the bike is in the 19-21 mph vibration range. With the clutch lever out engine braking past 20 mph, I don't notice any extra vibration, though there is inherently more vibration and inertia present when the engine is engaged with the drivetrain.

The only thing I have adjusted recently is the chain tension.

Would it be possible that chain adjustment could cause the above symptoms? Perhaps it could be rear wheel misalignment, though when I adjusted the chain tension, I meticulously aligned the rear wheel with the alignment markings on each side.

Anything else that could be causing this symptom? Thanks in advance for the help. Hoping to get this diagnosed quickly as I plan on putting roughly 1000 miles on the bike this weekend :/
 

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Chain or wheel balance. If when you adjusted the chain you didn't adjust it per the tightest part of the chain then it could be over tight. All chains have a tight spot. Some are negligible others are extreme. It's important to find that spot then adjust it there. If you tighten the chain at the loose spot the. When the tight spot comes around it will be overly tight.

My bets on wheel balance though.
 

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Discussion Starter · #3 ·
I've experienced a wheel imbalance before, and this doesn't feel like it. The vibration is more like a grinding rather than an out-of-balance washing machine. I could potentially see the chain being overly tight. The issue is that I find the quick shifter responds much better (less jerky) when the chain is slightly on the tight side, though it does measure within specification. Thanks for the feedback.
 

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Not sure about your problem but the alignment marks are but a guide - lots of posts on here about the inaccuracies of relying just on alignment marks - some bikes are OK, others are way off. I measure the adjustment rods with a steel ruler (or calipers) to make sure each side is exactly the same and confirm using the 'string' method...good luck
 

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Not sure about your problem but the alignment marks are but a guide - lots of posts on here about the inaccuracies of relying just on alignment marks - some bikes are OK, others are way off. I measure the adjustment rods with a steel ruler (or calipers) to make sure each side is exactly the same and confirm using the 'string' method...good luck
Where do you measure to/from? The end of the swing arm?
 

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Have attached an image, not a great shot but should give you the idea, use a steel ruler as a tape measure is not accurate. Normally the lock nut wouldn't be locked in place during adjustment - this photo is after I've finished. If both sides are the same it's bang on, and the indicators should be pretty much the same also. Just a guide again, then I string the bike, if you're not sure on that procedure it fairly easy, google "cycle world string" and it's the first article, hope this all helps, may not solve your issue but handy anyway.
 

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Discussion Starter · #8 ·
I'll bet on a too tight chain and I don't care what the quickshifter likes.
The specification for chain slack per the owners manual for '14 Street Triple is 0.5-0.9 inches. I currently have mine set at 0.9 inches, however the spec is much tighter than that of the Daytona (1.1-1.5 inches) and the general recommendation I see on the web is 1.25-1.5 inches.

What is the consensus on the factory recommendation for chain slack on the latest gen Street Triple? Good or too tight?
 

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I've never seen it in a spec, but how hard you push and pull on the chain can make a huge difference in what is the measured slack. If you push/pull hard and get a min measurement it seems really like no slack at all. I used to do this and had trouble years ago. Nowadays I just flop it up and down with my fingertips without putting much tension on it when I measure. I set my '11 at 1" total limit of chain centerline movement but that's in the middle of the older spec.
 

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Have attached an image, not a great shot but should give you the idea, use a steel ruler as a tape measure is not accurate. Normally the lock nut wouldn't be locked in place during adjustment - this photo is after I've finished. If both sides are the same it's bang on, and the indicators should be pretty much the same also. Just a guide again, then I string the bike, if you're not sure on that procedure it fairly easy, google "cycle world string" and it's the first article, hope this all helps, may not solve your issue but handy anyway.
Thanks!
 

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The specification for chain slack per the owners manual for '14 Street Triple is 0.5-0.9 inches. I currently have mine set at 0.9 inches, however the spec is much tighter than that of the Daytona (1.1-1.5 inches) and the general recommendation I see on the web is 1.25-1.5 inches.

What is the consensus on the factory recommendation for chain slack on the latest gen Street Triple? Good or too tight?
Just checked my '15. It's at 0.75" slack in the center of the run. That is lift up to max. chain up to down with very slight pressure. Measured top of chain to top of chain.

For alignment, I "strung" the bike and then count bolt "flats" to tension the chain. In all honesty, you can't use a ruler of any type, the adjustments are too fine to measure accurately.
 

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I had a similar vibration/grinding feeling after my chain was hastily adjusted at a shop. Came home and aligned the rear wheel/sprockets using the motion pro tool and it went away. Feels butter smooth now. My alignment marks are inaccurate as well. One side has the dot completely covered, other side shows half a dot.
 

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I use the loosest part of my chain to adjust it. If I can't push it up far enough to contact the underside of the swingarm, it's good. I'd rather run a bit on the loose side, everything seems to work better that way.
 

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Ive got that same friggen feeling you do! Thought maybe it was a wheel bearing. Noticed i also had a strong vibration felt through foot pegs when accelerating. Do you have that as well?
 

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Discussion Starter · #15 ·
I changed the tires (therefore rebalancing them) and loosened the chain in one fell swoop. The vibration seems to have gone away/is now present around 14 mph and is much weaker than it was at 20 mph. I suspect a chain a little on the tight side was to blame, though it was within specification. My chain slack is now at ~1.2 inches, which is outside of the specification, but everything I've read says the looser the better.
 

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I'm experiencing the the same issue right now. The rear wheel is as straight as I can measure with an engineering scale, and the chain slack is at 1.25" right now (originally started at 1" moved out to 1 1/8", and now to the current). So, my question is, how hard do you fellas exactly pull up and down on the chain to get your measurements? Does it matter if the rear wheel is on a stand or on the ground?
 
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