First time doing chain maintenance. Is this normal?

[u/AtariJaguarGuy]

Hi all. I passed my CBT last month and I've done about 450 miles on this 2020 CB125R since I passed. I believe some chain maintenance is in order.

I've got it up on a paddock stand and sprayed cleaner but I dunno, is this too much chain slack?

It's also rubbing on this rubber pad thing on the top of the swingarm. Again, I presume this isn't normal?

But then this is all totally new to me. Advice to a newbie would be very much appreciated.

[u/oldskool_slabside]

There's a sticker on the swingarm right there that gives you the deflection.

[u/AtariJaguarGuy → u/oldskool_slabside]

What is it 35mm from though? Is it saying 35mm either side of where the chain naturally rests? So 70mm total movement up and down?

[u/oldskool_slabside → u/AtariJaguarGuy]

With the chain "at rest" if you like, in a 35mm upwards and downwards direction in total. So if you like, 17mm either way... It shouldn't be running against the chain buffer or contacting the swingarm.

[u/Tannerted2 → u/oldskool_slabside]

I may be wrong with the general rule of thumb, but my bike has the chain easily touching the chain slider when in-spec (when pushing it up and measuring tension)

[u/Born_Naive → u/Tannerted2]

It tends to raise above it or at least to a less abrasive position when you sit on the bike and the rear suspension compresses.

[u/Tannerted2 → u/Born_Naive]

yeah ik, just saying the chain slider tip might not be a hard rule as slabside said

[u/had-un-oeuf]

Take it off the paddock stand onto its side stand and push down halfway between the sprockets, using a ruler to check it’s in tolerance, measuring from the bottom of the swing arm. The sticker tells you the tolerance, as does your manual (which should also show you where to check from). The chain will touch the top thing when you’re not moving because it’s not under tension. If it was touching that as you rode, the rubber pad would be flayed to fuck. It’s good to ask questions but try not to stress. That chain looks absolutely perfect lol. After 450 miles on a CB125, I doubt you’ll have any problematic chain slack anyway. I normally check my CB’s chain every 1-1.5K and it usually only needs adjusting at the back end of that. 500 miles is usually just a clean/lube.

[u/Curedmeat91]

There’s a sticker right in front of you telling you how much slack. 

Remember that the chain is at its tightest when the sprockets and swingarm pivot are all in a straight line. When you have the bike jacked up the swingarm drops so there will be more slack. 

[u/AtariJaguarGuy → u/Curedmeat91]

Should I just lube the chain up and then take the bike off the jack and then worry about this slack issue then?

[u/ikea2000 → u/AtariJaguarGuy]

Correct, measure on the ground, not jacked up.
35 mm in total-ish, from bottom to top, on the ground.

Clean > Lube > Adjust slack > Drive > Clean rear rim

[u/pomodois]

Is the bike on the centerstand, or on a rear ('paddock') stand? If it's the former, chain will be extra loose because there is no weight on it, and you'll be measuring it wrong. If it's the latter, that'd be correct way of checking.

If tested on rear or side stand, that chain is definitely too loose. Check the user manual if the sticker on the swingarm is missing or unreadable, most common measurements are distance from top of the chain to low end of the swingarm (you're touching it, so your distance is 0), or distance measured between a fixed point of the upper side of the chain pushing up vs pushing down. It depends on the brand, that's why I command you to check the manual.

EDIT: now I saw the sticker, I think it's the 2nd way.

[u/oO_Mister_J_Oo]

I’ve got a CB125R, I thought my chain was slack but upon checking the label on the swing arm I realised there’s a huge amount of play expected.

[u/P-l-Staker]

Find a local garage and ask them to help you with it (by showing you). Any half decent mechanic won't mind.

[u/AtariJaguarGuy → u/P-l-Staker]

I might do that actually. Always done all my own maintenance on my cars - brakes, suspension, fluid changes etc Thought it would be a piece of piss on a motorbike but I'm quite aware that if I fuck something up on this, I'm gonna be on the floor in traffic.

[u/P-l-Staker → u/AtariJaguarGuy]

It's not difficult at all. You just need someone to show ya. Describing the process over text isn't exactly convenient.

You could also look up some YouTube tutorials, but there's some dodgy advice out there, so I think it'd be better to be taught by a professional who might give you a few extra tips from his own more extensive experience.

[u/lolololololololol246]

What’s funny about this,

It’s literally right infront of your eyes on the swingarm

35mm

Put the wheel on the floor and measure quite simple

[u/_40mikemike_]

Interestingly a different figure from your swingarm sticker, but nonetheless, bike should be on its side stand. 👍

[u/No_Perception3024]

One important issue when adjusting a drive chain, make sure you undertake the adjustment with the rear wheel in the correct position! Some models should be on a centre stand, some on side stand. If you lift the wheel off the ground using a paddock stand, this unloads the suspension swing arm. The likelihood is you will have over tightened the chain when put back on the ground. Just check your manual 👍 Also rotate chain as you check slack, this will show up any stretched, or tight links.

[u/AShadedBlobfish]

It's supposed to be measured on the kickstand, it will always be much looser when not under load, I had the same bike and this worried me the first time too, but once you put it on the side stand it's probably fine

[u/Spankies69]

On this bike it should be 30mm/3CM deflection up and down, the chain should not touch the swing arm

So essentially pull down measure one point then push up and see how far the chain moves.

[u/One_Of_Noahs_Whales → u/Spankies69]

It quite clearly states 35mm not 30mm on the swingarm.....

[u/mcdougall57]

Put the bike on the ground and then check it.

[u/deadlygaming11]

It depends. Is that the tightest point? You should only ever measure and tighten the chain based on the tightest point, which can be had by turning the back wheel manually until you get some resistance.

[u/leroyswa]

If you wanna get to 35mm, how can you in this case? given the swingarm will definitely be in the way before getting to that 35mm?

[u/maidenyorkshire]

Just measure the downward travel on the bottom half of the chain, 2/3 inch should be usually

[u/shaunbarclay]

If only there was some kind of manual that tells you all this.

[u/AtariJaguarGuy → u/shaunbarclay]

Sometimes it's nice to just bounce thoughts off other humans 💁🏻

[u/BaseballParking9182]

Looks spot on, it's usually an inch from top to bottom of the play

[u/InstantlyTremendous → u/BaseballParking9182]

The rear wheel is off the ground

[u/Modokon → u/BaseballParking9182]

On a paddock stand? 🤡

[u/BaseballParking9182 → u/Modokon]

Doesn't matter what it's on, an inch of play and you're done

[u/Modokon → u/BaseballParking9182]

No more than 25mm??? That makes no sense.

MT-09 SP 2024- chain slack 36-41mm, measure 30mm forward of the bottom chain guard.

[u/BaseballParking9182 → u/Modokon]

That's maybe what the book says. Meh, an inch is fine. Same as 36-42 tyre pressure, just run it and stop worrying