Chain wear confussion

[bonne]

The SM1050 (Service manual for the 1050) on this site says on page 0B-19:

"count out 21 pins (20 pitches) on the chain and
measure the distance between the two points. If the
distance exceeds the service limit, the chain must be
replaced.
Drive chain 20-pitch length
Service limit: 319.4 mm (12.57 in)"

And then there is a picture that shows a caliper counting 20 pins

My chain is not the OEM but an EK 525 (extra duty) that has 40.000 km on it - shows no sign of wear and neither do the rear sprocket) and beside the initial km's I have only tightened it once (two half turns with the chain adjuster). There are plenty of more space to tighten.

If I use AI and ask how to check a 525 chain, it tells me that the service length is 329.6mm which is far from what the SM1050 says.

So I am confused. How to accurately tell if my EK chain is worn and ready to be changed?

[bonne]

40.000 km may sound like a lot especially because I ride the MC hard with a lot of load and I never clean the chain - I just lube it on the inside on a short length just before I drive and if the rollers are shiny, I give it an extra squirt oil.

[Rusty Nuts]

Hmmm, AI. As far as I can tell, AI is some of the most powerful computers in the world asking everybody else's computer questions and making a guess based on all the answers. The old GIGO acronym springs to mind. A service manual would be more trustworthy, even taking into account the different chain manufacturers.

[bonne]

Absolutely... AI can ofte be way off... that is why I ask in here.

But also about the way to measure the length... Should I measure center of pin 1 to pin 20 or the outer side of the rolers... it is as if the manual indicate pitches (and 21 pins)

[Rixington43]

The picture in the manual shows 20 pitches or 21 pins, it's just that whoever did their diagram didn't get the numbers lined up quite right above the picture.
Measure 21 pins with the first pin counted as 1 and not 0, so 20 pitches of chain within your caliper and use the service limit listed in the manual.

[bonne]

So max  319.4 mm from the center of pin 1 to the center of pin 21 on a stretched out chain?

[bonne]

I just went down and did a measurement. Chain length is in fact 319.4 mm (well, the .4 thing is not that accurate... but close).

So you can probably imagine my next question...? How serious should I take this measurement. Like: "oh oh... the chain can break any second" or I should start to think about ordering a new one while still riding the MC for another 1.000 km?

[bonne]

I am not at all able to pull the chain like this:
https://www.revzilla.com/cdn-cgi/image/onerror=redirect,format=auto,q=75,w=778/blog_content_image/image/64931/gallery/IMG_4352.JPG
as indicated on https://www.revzilla.com/common-tread/how-to-determine-when-your-motorcycle-chain-and-sprockets-need-to-be-replaced

That is why I think that the chain is still OK - but I am not sure...

[Joe Rocket]

I have over 46k kms on my original chain and I cannot pull a link off the back of the rear sprocket, not even 1 mm. I have been told by a rider behind me there is a mechanical noise coming from the rear relative to bike speed so assume there could be a tighter link somewhere but I can't find it. I can't feel anything through the footpegs either.

I am in no hurry to change chain and sprockets and will maintain my regular chain maintenance. I suggest you do too bonne until a definate indicator tells you otherwise. 

[nigel s]

If you want to be really OCD, get a  "go no go " tool  like the one below drop it on and if it goes all the way down , time to replace.
I have one for my E bike, 1x 12 gearing makes chain maintenance very important for easy shifting. Plus a new chain is £30  ( easy to find the money ) a new gear set £150 ( Not so easy to find ) ,  two chains to a chainset is doable before it jumps around...so I tend to get OCD about it all

https://www.amazon.co.uk/Indicator-Checker-Motorcycle-Motorcross-Enduro/dp/B0CT5G87SG

 For my motorcycles I have used a scottoiler for decades now and chain replacement is governed by sprocket wear not chain wear for me.
 When I need new sprockets..new chain   

Ho Hum