Chain Slack

[potter0o]

I have been keeping my chain on the looser side. Another rider mentioned that it look loose. What are others keeping their slack at?

 

[Rabbit]

I have been keeping my chain on the looser side. Another rider mentioned that it look loose. What are others keeping their slack at?

I just tightened mine the other day. Went from 45mm to 30 mm. The manual says to keep it between 30-40 mm, and not to exceed 60 mm. Now that I have done the tightening one I likely won’t let it exceed 40mm

 

[Deleted member 1183]

I tend to be on the loose side also.

When I first get a bike I undo the bottom shock bolt while on the centrestand. Then I lift the wheel until the countershaft, swingarm axle and rear axle are in line. In that position I take almost all of the slack out of the tightest part of the chain without getting it too tight. I put all back together and then note the slack again as My go to measurement for the future. On my X-Adv it is the only proper way to set the chain slack because the swingarm is not only long, but also an unusual shape with the chain guard also complicating things.

 

[dduelin]

Owners manual recommended 30-40mm checked on side stand.

I always check it on the center stand and keep slack measurement between 35 and 45 mm, adding 5 mm to the recommended 30-40 mm because use of center stand adds the extra amount. Because the chain will develop tight spots over time I rotate the wheel 90 degrees or so after the first measurement and check it at 3 or 4 different spots.

 

[670cc]

Owners manual recommended 30-40mm checked on side stand.

I always check it on the center stand and keep slack measurement between 35 and 45 mm, adding 5 mm to the recommended 30-40 mm because use of center stand adds the extra amount. Because the chain will develop tight spots over time I rotate the wheel 90 degrees or so after the first measurement and check it at 3 or 4 different spots.

I do as dduelin describes, using the add 5mm method when adjustment is done on the centerstand. That puts the recommended range at 35-45 mm. I set slack for 40 mm on the centerstand, no tighter. Last fall I accidentally set it for 35 mm, but the chain sung loudly and I had to readjust to back it off to 40.

A loose chain is a happy chain that lives a long life.

 

[MZ5]

I also set a bit loose. About 1 3/4” - 1 7/8”, which is close to the 45mm mentioned above. I don’t like the ‘singing’ when I adjust it much tighter, and I just don’t see any particular advantage to adjusting it tighter. There is less overall driveline slack for low-speed maneuvering if one adjusts tighter, but I’m not at all sure I can tell the difference between the tight end of Honda’s spec and where I like to run my chain.

 

[the Ferret]

Do you guys pull it down, then push it up to check chain slack or just push it up?

 

[670cc]

Do you guys pull it down, then push it up to check chain slack or just push it up?

Measured at the midpoint between sprockets on the bottom run. Ruler vertical resting against bottom of swingarm. Push up and note measurement at center of chain pin. Pull down and note measurement at center of pin. Difference is the chain slack.

If when I push up, the chain contacts the swingarm, then there’s probably too much slack and it’s really not worth measuring.

Procedure is in the owners manual, and there may even be a graphic showing the measuring method on a label on the chain guard.

 

[the Ferret]

I've seen the graphic in the manual and it's not really clear, and certainly doesnt verbally instruct to pull down and then push up. However, it's only in the last few years that I've heard/read of pulling the chain down, and measuring up from the lowest point to the highest point.

I started working in motorcycle shops in 1972 up until 1989, ( and riding and adjusting chains on motorcycles since 1965) and never saw or heard any mechanic pull down and then push up. They only pushed up from a chain at rest. Dont know if it's right or wrong, but it's the only way I have ever seen it done.

Wonder how much the difference between the two methods would really be?

 

[MZ5]

The difference is noticeable.

 

[bigbird]

I started working in motorcycle shops in 1972 up until 1989, ( and riding and adjusting chains on motorcycles since 1965) and never saw or heard any mechanic pull down and then push up. They only pushed up from a chain at rest. Dont know if it's right or wrong, but it's the only way I have ever seen it done.

Wonder how much the difference between the two methods would really be?

How about you do the legwork on your new chain.
Measure it using both procedures, and report back with your findings.
Thanking you in advance, as I'm way too lazy to try it on my chain.

 

[the Ferret]

I may just do that and see

 

[potter0o]

Thanks all for the feedback. I usually aim for the top end of the tolerance and tigthen when I tip over +10mm. Basically making sure that at the maximimum it is 5mm below where the manual notates it may cause damage to the frame. I have not had any issues with it but it made me curious to the practice of others. I do the 4 points method and check it as part of my chain lube every 800 ish KM. It doesn't move much but it makes happy that I know where it is at.

 

[670cc]

I've seen the graphic in the manual and it's not really clear, and certainly doesnt verbally instruct to pull down and then push up. However, it's only in the last few years that I've heard/read of pulling the chain down, and measuring up from the lowest point to the highest point.

I started working in motorcycle shops in 1972 up until 1989, ( and riding and adjusting chains on motorcycles since 1965) and never saw or heard any mechanic pull down and then push up. They only pushed up from a chain at rest. Dont know if it's right or wrong, but it's the only way I have ever seen it done.

Wonder how much the difference between the two methods would really be?

I guess if you were to examine the illustration and assume it is truly realistic, the top run makes a straight line from sprocket to sprocket, indicating that it is tight. The two measurement positions of the bottom run show the chain above and below the straight line between sprockets. It seems the only way to obtain those conditions is to push up and pull down on the chain. If the chain was not pulled down for the down measurement, the top run could droop from the chain‘s weight, affecting the measurent.

Image taken from 2021 NC750X owner manual:

 

[dduelin]

I'm not sure this is one of those critical measurements unless it's too tight.

I push up from the chain's catenary position and measure the distance to where the chain comes tight. So I'm measuring up from it hangs loose to where I can't push it anymore. I don't pull it down first.

 

[MZ5]

I both push up and pull down. If I did not pull down, I bet my slack would be exactly in line with dduelin’s. In fact, I’ll go out into the 100-degree garage right now and measure it…

 

[MZ5]

Good news! The garage is only ~95 yet!
(-:

I just did a quick check on the kickstand. I didn’t rotate the tire to check multiple points, so take this for what it’s worth.

If I push up and pull down, my chain slack is 1 3/4” at the moment. If I do _not_ pull down, but instead just let the chain fall from the pushed-up position, the slack is 1 1/2”.

So, in the particular spot on my bike’s chain where I just happened to check, and with the bike on the kickstand, I get basically 1/4” difference in slack when pushing _and_ pulling, vs. just pushing.

 

[670cc]

Good news! The garage is only ~95 yet!
(-:

I just did a quick check on the kickstand. I didn’t rotate the tire to check multiple points, so take this for what it’s worth.

If I push up and pull down, my chain slack is 1 3/4” at the moment. If I do _not_ pull down, but instead just let the chain fall from the pushed-up position, the slack is 1 1/2”.

So, in the particular spot on my bike’s chain where I just happened to check, and with the bike on the kickstand, I get basically 1/4” difference in slack when pushing _and_ pulling, vs. just pushing.

Thank you for making and reporting those measurements, MZ5.

Another minor factor with sidestand chain slack measurement, on a manual transmission NC, is whether the transmission is in neutral. If the manual is in gear, there could be a rare case where the top run of chain has slack in it, having taken it away from the bottom run. If the transmission is loading the chain while at the same time the rear wheel cannot move, there could be trapped slack in the top run. This would make the bottom run, where the measurement is made, tighter than expected.

If the measurement is done on the center stand, or the manual transmission is in neutral, or the bike has a DCT, this would not be a potential problem.

 

[MZ5]

Good point about in-gear vs. neutral, so I note here for the record that my bike was in neutral when I made the above measurements.

 

[bigbird]

Comparing the specs on my '20 vs the '21 using both year's owners manual, the chain slack spec has been changed from the 20's 30-40 mm to the 21's 25-35mm.
I 'm guessing this is due to either the change in sprocket sizes for both the NC and NCX for '21 and/or the lower ground clearance of the '21 or ?
The chain for both models of '21 is 114 links, whereas the '20 had 114 for the NC and 112 links for the NCX.

New owners of the '21 should be very vigilant when it comes time to replace chain and sprockets, as they shouldn't go by here say and what's posted on forums, only by what's written in their owner's manual.

Also, all the DIY oil and filter change, DCT filter change, coolant change, and spark plug change instructions are missing from the '21 owner's manual.
Looks like Honda is trying to get all new owners away from doing their own maintenance and relying on dealerships.
Thank goodness for Helm and their service manuals.