Guys, New here and I have searched around trying to gather info for chain tension being my bike is newer, along with being modified info is a little harder to find.

I have a 2018 797 with a 2014 796 single side swingarm to fitted along with new sprocket changes to 14 & 45t (797 Stock was 15/46t and 796 was 15/39t) I wanted the short ratio

the 796 sss shock mount point was modified to fit the further offset of the 797

currently what I "think or eyeball" is ~34/35 with difference and free sag 62mm between pins measured center @ base of the swingarm.

Input would be helpful ?

Actually, I'm a little confused by the chain tension on the 796, myself... so I'll be curious what others might have to say.  It seems pretty darned tight at 62mm...

FWIW, that's an odd gearing selection.  True, the stock 796 is 15/39, which is way too tall, but going 14/45, at least by my math, doesn't make a lot of sense.  I debated just going to a 14T front, but decided in the end, after reading about how a chain handles the tighter radius of the 14T, to go bigger on the rear... I just installed a new set of 15/41 on my 796, along with a new chain.  It has helped drive-ability an insane amount... around town and even on the highway.  I can actually use 6th gear, now.

The number (XX mm) isn't important.
It doesn't matter what size of front / rear sprockets you have.

The drive chain tension gets tightest when counter shaft sprocket , swingarm pivot, and rear sprocket are all lined up in-line.
You want around 5mm of free play when rear suspension strokes and all three of them (both sprockets and swingarm pivot) line up.

So, put the bike up on the swingarm stand, rotate the wheel, find the tightest spot of the chain.
Put the bike down from the stand.
Have a helper to push down (or sit on) the bike, to stroke rear suspension.
Adjust the tension.

For future reference, put the bike up on the stand again, and measure the free play of the chain. write down the number some where.
(NOTE: when you lift up the chain under side of the swing arm, DON'T push it up all the way (as much as you could push it up). If you do that, you can see upper portion of drive chain gets pulled and lifts up from the plastic slider. THAT'S WRONG.
The proper way to measure the slack is to slowly push up the chain underside of swingarm, stop pushing up when upper portion of the chain starts lifting from the slider.

Quote from: S21FOLGORE on December 12, 2019, 12:09:29 AM
The number (XX mm) isn't important.
It doesn't matter what size of front / rear sprockets you have.

The drive chain tension gets tightest when counter shaft sprocket , swingarm pivot, and rear sprocket are all lined up in-line.
You want around 5mm of free play when rear suspension strokes and all three of them (both sprockets and swingarm pivot) line up.

So, put the bike up on the swingarm stand, rotate the wheel, find the tightest spot of the chain.
Put the bike down from the stand.
Have a helper to push down (or sit on) the bike, to stroke rear suspension.
Adjust the tension.

For future reference, put the bike up on the stand again, and measure the free play of the chain. write down the number some where.
(NOTE: when you lift up the chain under side of the swing arm, DON'T push it up all the way (as much as you could push it up). If you do that, you can see upper portion of drive chain gets pulled and lifts up from the plastic slider. THAT'S WRONG.
The proper way to measure the slack is to slowly push up the chain underside of swingarm, stop pushing up when upper portion of the chain starts lifting from the slider.

You know what... that all makes perfect sense.  I didn't realize until now that a bigger rear sprocket would alter the measurement at the midpoint... no wonder it was so frikkin tight.  And, yes, I was mashing up on the chain as hard as I could.  Jeepers, I'm dumb...

Note that the manual for my 1100Evo states that the measurement is from the alloy part of the swingarm. Check your manual to be sure. Measuring from the plastic chain runner loses at least 10mm. Modern chains appear to have a good tolerance for being on the loose side, so I err on the loose side.
I recently noticed a customer bike (1100 Evo) with the chain adjusted on the loose side measuring 61mm from the plastic chain runner (clearly serviced without consulting the manual).

Jumping in to further confuse or with any luck clearify a little ....

The 696/796/1100 bikes have the engine (and swingarm axle) higher in the frame than earlier bikes with the same engines. One of the results is that the swingarm+chain drops steeper AND THEREFORE MUST HAVE MUCH MORE SLACK WHEN STANDING STILL ON IT'S OWN. It's not 60 mm loose with rider and on the road.

Maybe the 797 doesn't have the engine in the same high position? If it doesn't, we're back to more 'normal' measurements despite the 796 swingarm.

Add the new and different measurements because of different/modified/adjusted suspension and we're back at the only secure way of measuring (and getting to know the bikes) which is described by S21F above (FWIW I'm using 10, not 5 mm)

Well hope this pic helps any  checked it with someone on the bike today seems I have ~5mm+ when moving chain and not lifting top run
https://flic.kr/p/2hYBQsu

Nice

Quote from: TNDrifter on December 12, 2019, 05:27:47 PM
Well hope this pic helps any  checked it with someone on the bike today seems I have ~5mm+ when moving chain and not lifting top run
https://flic.kr/p/2hYBQsu

Someone on the bike is probably/maybe not good enough. Are you sure the front sprocket, swingarm axle and rear wheel axle were on an absolutly straight line? If your helper isn't heavy enough, compress frame/axle with a ratchet strap.

Quote from: stopintime on December 13, 2019, 01:59:42 AM
Someone on the bike is probably/maybe not good enough. Are you sure the front sprocket, swingarm axle and rear wheel axle were on an absolutly straight line? If your helper isn't heavy enough, compress frame/axle with a ratchet strap.

Page 189 of the owners manual is pretty clear. Covers all the relevant points. I'm not sure why chain tension needs to be over analyzed.

40-42 mm at a point halfway between the sprockets.

Quote from: ducpainter on December 13, 2019, 04:57:44 AM
Page 189 of the owners manual is pretty clear. Covers all the relevant points. I'm not sure why chain tension needs to be over analyzed.

40-42 mm at a point halfway between the sprockets.

One bike, another swingarm. Could require different methods.

Quote from: stopintime on December 13, 2019, 05:34:01 AM
One bike, another swingarm. Could require different methods.

Missed that.

Carry on.

Well today I put the bike on a jack removed the Shock and elevated the swingarm throughout its range of motion to the distance of max shock travel. Swingarm maintained around 5-10mm of free play. Put it back together with a final check it has 40mm with difference measurements. So it should be good to go (797 manual notes 40-42)
Thanks for the input everyone!