Changing the Chain on a Honda CG125

I know, this is out of chronological order, but I had this saved as a draft and forgot about it.
Anyway, here you go.

So I've decided to change the chain on my motorcycle.  I had changed the cush bearings, and I was going to change the chain at the same time, but I discovered the existing chain requires a special tool to remove - one I didn't have.
I had purchased a chain and sprocket kit for the bike; it claimed to be the OEM for the CG 125, but I later had my suspicions.  I purchased the kit not knowing the first thing about motorcycle chains, other than the fact that they need maintenance and changing.  After installation, I did a bit of research on the chains and discovered that the bike comes from the factory with a 14 tooth front sprocket and a 44 tooth rear sprocket.  The kit I purchased contained a 15 tooth front sprocket, so this has the (negligible) effect of a higher top speed, and fewer revs at any given speed, ie if the bike was turning 4000rpm at 30mph, it was now turning at 3725rpm.  Not a big deal, but the end effect is I change gears later, and I haven't got as much power on tap at 30mph as I used to.  It's a tiny effect, but on a wee bike like mine, every little bit helps.
I was changing the chain on my bike for two reasons - one, as I said, it is a regular maintenance item, and I have no idea how long the chain had been installed; and second, there were some links that were siezed and were not giving me the smoothest of rides.
The process is fairly straightforward - you expose the chain, remove the tension, break one of the rivets, grease the new chain, clip it in place, and then adjust the tension.
To do the job, I used the following tools:

• an 8mm, 10mm, and 17mm socket with the appropriate ratchet (for removing the various chain covers)
• a few ratchet wrenches, 8mm and 10mm (also for removing the various chain covers)
• a 1/2 torque wrench (for tightening the axle bolt)
• an adjustable wrench for the axle nut (its I think 24mm, and I didn't have a wrench for it)
• a chain rivet breaking tool (about a tenner off ebay - worth the money for sure)

So here are the steps.
First I removed the chain guard covering the top of the chain.  One nut, one bolt, very easy to do.  I then took the front sprocket cover off - two bolts for this one.  Again, very easy to do.
I then loosened the axle bolt and nut, and pushed the wheel towards the motor - this removed the tension from the chain, making it hang low.  I did not adjust the alignment nuts on either side; with the tension off, they could move freely off of their seat on the swing arm.
I had a look at the chain, and found a link with some rivets that looked different from the others, and figured this was a good place to break the chain.
The chain breaking tool is fairly straightforward to use - basically its a bolt with a threaded bolt inside it - the outer bolt holds the chain in place, and the smaller bolt inside is screwed down to push the rivet out of the link.  Its easy to do; the most careful you need to be when removing a rivet is getting the alignment correct.  The tool helps make it easy.  Here you can see how the rivet breaker is in place.  I have a breaker bar on the smaller threaded bolt inside to help push the rivet out.

 It doesn't take a great deal of force, but you do have to push a bit.

Once the rivet is broken, the chain pretty much falls away.  Mine was a bit stiff so I had to wrestle it off a bit (woof woof).

Here are the sprockets, all chain-less.

 (Note how wonky the gear shift lever is - this is the result of it being bent back into place with a hammer after my first fall.)  The new sprocket is in place; this was done when I changed the cush bearings.

(And yes, I have removed the pillion passenger's foot pegs - they kept falling down out of the storage position.)  This image also shows the original rear sprocket.  I couldn't change it because the pins that sit in the cush bearings wouldn't come out.  I have to buy new pins for the new rear sprocket.

I then got the new chain out, and grease it up with the can of chain lube that came with the chain kit, it was a white lube which helped make it easy to see if I had missed any spots.

 

There is a separate link in the kit, which is attached with a small clip.  Pretty important, this piece.  I gave it a good soak in the white chain lube as well.

Next I pushed the wheel as far forward as I could, and tightened the axle nut to hold it in place.  This made the two sprockets sit as close together as possible, to help get the chain on.  

So I draped the chain in place on the rear sprocket, and pulled it to the front sprocket.  This is where I ran in to some difficulty - it wouldn't reach.  

It was off by only a tiny bit, so with a bit of coaxing and pulling and pushing, I got the link to push into place.  Taking careful note of the instructions, I slid the pin in place - its like a cotter pin, but flat and holds the link together.  

At this stage, I wasn't sure if I needed to mushroom the rivet.  I thought I had read in the instructions that I had to, but damned if I could find them.  I figured better safe than sorry, so I decided to mushroom them.

I added the pressing bit into the chain breaker.  It had a small ball bearing - like sphere of steel in it, which, when pressed into the face of the rivet, would squish the metal, flattening it.  (Hard to describe, but it basically makes the force of screwing the bolt tight compress the rivet, flattening it.)  I attached the tool very carefully - I remember reading that its imperative to get it lined up correctly or it will crush the pin in the wrong spot.  Satisfied it was square, I screwed the bit against the rivet.

In the below image, you can see at the bottom of it is the factory-flattened rivet.  At the top is an uncompressed rivet with the clip in place.  The tool is attached to the middle rivet, and is about to flatten, or mushroom it.

I then checked the tension on the chain, and found it to be quite loose on the sprockets.  I don't know how that worked, considering it was in the same place a minute ago and it was too tight to get together....

Anyway, I adjusted the tension the standard way - 2.5cm of play in the middle of the chain, tighten the axle nuts and make sure the wheel is aligned - easy to do on these bike with the marks on the swing arm to help you line up.

With that done, I started the bike and put it in gear, carefully watching the chain and the sprockets - keeping my fingers away.  All seemed to be going the right way, nothing was loose, and there appeared to be no binding in any of the links.  so, I took the bike out for a spin and again, the character of the bike had changed from an unpredictable bucking bronco to a smooth, easy to ride, forgiving little pony.  Definitely worth the effort.

After my short test drive, I lubed the chain up again (I imagine some of it was flung off when I was riding), and parked it, letting the lube soak in over night.

Job done.

~~~~~

As I mentioned, I wrote this a while ago.  I can now update the fact that the bike is now running very well - the combination of new cush bearings and a new chain has made the drivetrain feel much for solid an predictable - the transfer of power is as smooth as my clutch will allow, and old Hank seems much happier for it.

The Thrills and the Spills of Motorcycling in London

So after having completed the cush bearing replacement, ole Hank has been running well and everyone seems happy.  I am finding the ride to and from work is quickly regaining its previous position of being the highlight of my day.  After my first spill, I was nervous and it showed - my riding was not smooth at all.  With some adjustments to the bike, and with more miles under my helmet, I am getting better and better - and faster.  Not that I'm fast, by any stretch!  Here's a short video of how fast I ride post-spill:

It had rained, and there was a real chill in the air.  It was about 5 degrees Celsius, so I was worried about frost.  Plus, this particular corner is almost a complete 360, and its a steep hill down - this is in Crystal Palace.  Keen observers will note that the Mini passes me, and then get stuck behind a queue of other cars.  His pass gained him absolutely nothing.  He did get to swear at me, though, so that's a win for him.  I guess.
The thing is, I was doing the speed limit when he passed me.  Sure, I took the corner slow, but you would think that if you saw a guy on a motorbike going slowly around a corner, he might be trying to be careful and not take risks - therefore maybe keep well back?  And maybe he also realises now that passing like this does nothing for him except make him more upset.
I have had this a few times, where I will obey the speed limit (or maybe go 5mph over), and I will be overtaken - sometimes undertaken! - by someone, and within sixty seconds, I sail right past them as they get stuck behind someone else in a car.  What's the motivation for this?  Why do cagers behave like this?
Well, as an ex-cager (and still a part-time cager), I think I can understand it.  If you're driving a car, and there is a bike in front of you that is making you nervous (driving erratically, weaving all over, going way under the speed limit), I get that you want to have the bike behind you rather than having the option of him going under you.  Fair enough!
What if the bike is going the speed limit, or only just a little bit over?  Is it worth getting past them?  Maybe, if they are clearly not in full, confident control of their bike.
So sure, there are situations where it is safest to pass the motorbike.  I get that.  If you do decide, in your car, that you want to be in front of a bike, can I humbly ask that you refrain from using your horn, or revving the engine so hard it sounds like its going to jump its motor mounts?  And maybe refrain from swearing and getting angry?

A few days ago, I had a similar experience to the one above.  I was making a right turn onto a road where the speed limit changes right away to 40mph.  I negotiate the corner successfully, and I start to gather speed, when a lad in a VW Polo decides he's annoyed with me.  Horn blasting, engine revving, he passes me at 50-60mph.  And he was bloody close when he pulled back in.  Sure enough, less than 400 metres along, he is stopped at a red light....
I knocked on his window, and he rolled it down.  I asked him why he had to pass me like that, and his claim was that because I was on L plates, I have no right to be in the middle of the road, I should stay next to the kerb!  I was a bit taken aback by this, and told him that I am a fellow road user, and I have every right to use the whole lane, and please don't use the horn like that as all it serves is to frighten me and increases my chance of nervously losing control of my bike.  When I lose control on a bike, the repercussions are a bit more painful than when a VW Polo goes into a skid!  He rolled his window up, still swearing at me, and took off - through the red light, no less.  I think he was feeling a bit sheepish and stupid.  At least I hope he was.  Maybe the next day he went and complained to his mates about how I was using the road, and his mates told him he was wrong and stupid.
Dare to dream, I guess.

Anyway, a spill story for you.
Last friday night I met a friend at South Bank, had a lovely time.  I left the area at about 10:30pm, heading home on my bike.  I approached the roundabout that is Charlie Chaplin Walk - the BFI iMax cinema.  I gained the first position at the roundabout, and waited for traffic to allow me a join when I feel a push and a jerk and my bike is falling out from underneath me!
I turn around, and sure enough, one of those Prius Uber taxis is there - he just rear-ended my on my bike.  I pick up my bike and drag it to the side of the road to check for damage.  The taxi driver looks stunned and shocked - he kept saying 'Are you okay?  I didn't see you!  I thought you went through!'
I was fuming - I was not happy.  I look at the bike, and it would appear the only damage was the L plate was broken on the back, and the right footpeg was bent up a bit due to hitting the floor.
I think I was intimidating him by not saying anything to him whilst I checked out my bike.  He was getting more and more agitated, running around me, saying 'its all my fault! I'm sorry!'
I finally look at him and say 'you scared the shit out of me!'  He apologises and apologises, until he says that we can settle this like gentlemen and he will give me £100 for the trouble.
The bike isn't hurt.  I'm not hurt.  I'm just a bit shaken.
I took the £100.

I guess the point is, things like this happen all the time.  It was a minor prang, nobody got their fists out, and we shook hands at the end of it.  Sometimes shit happens and we can be grateful we walk away with all our facilities.  I mean, what if he hit me harder, and he pushed me into traffic and I got run over or worse the bike gets run over?
I'm just glad I get to ride - a few minor inconveniences and some rude or dangerous drivers make it less fun, but at least I still get to ride.

Changing the Cush Bearings on a Honda CG 125

Okay, I know its an obvious title, but I'm hoping that it may help someone who is doing a search one day.  There is very little out there with regards to showing how to change cush bearings on a CG 125 considering how popular and common these bikes are.  So, I will try to explain how they work and why they are there, and how to replace them.
First off, to explain what the cush bearings are, and what they do.
My bike had this thing where if I touched the throttle, even a little bit, the bike would jerk forward underneath me.  Also, if I was pottering down the road at a constant speed, the bike would feel like it was stumbling along - almost like it was misfiring.  After doing a bit of research, I discovered the things called cush bearings might be the culprit.
Basically, they are rubber bushings that sit in the hub of the drive wheel, acting as a shock absorber for the transition of power from the rear sprocket to the wheel.  On a push bike, there is no absorption; the power is directly transferred from the sprocket to the wheel hub.  Motorcycles have the bushings to help make power delivery smooth, reducing stress on the drivetrain, whilst allowing power to transfer to the wheel.
On the Honda, there are four bushings pressed into the rear wheel hub, and the sprocket has four pins that sit in the bushings.  The sprocket is not attached or bolted down in place, it is held only by the chain and the cush bearings.
To access the bearings, you have to remove the rear wheel.  To do this, I first put the bike up on a paddock stand.  Which caused my first problem....  The exhaust pipe prevents access to the swingarm, where the paddock stand lifts the bike!  It sits lower than the swingarm, and is about 15mm away from it, so I had to remove the exhaust to get it up in the air.  A bit of a pain, but seeing as it's one bolt at the back and two capped nuts at the engine, it's pretty easy to do.  (Plus it gave me a chance to examine the pipe, and clean it up - discovered a small hole in the bottom and some rust underneath.)
With the bike up in the air, I then removed the chain guard, and disconnected the left shock absorber.  I then detached the rear brakes, and the brake bar - this is the metal bar connected to the brake assembly hub and the swingarm - it basically keeps the brakes from spinning along with the rest of the hub.  I pulled out the axle, which is held on by a simple nut - there is a spacer on the exhaust side of the wheel, which will fall out and roll under your workbench if you're not careful.

I pushed the wheel as far forward as I could (towards the engine).  This gave enough slack on the chain for me to pull the chain off the rear sprocket.  I also pulled the front sprocket cover off; this is just a plastic cover held on with two bolts, sitting next to the crankcase.  When it comes off, there is also a chain stay that comes with it - this is a crescent shaped piece of metal that keeps the chain close to the front sprocket.  Here is a photo of the front sprocket, with the chain stay highlighted with an arrow.  Note the copious amount of chain grease that's been flung off the chain.

It may be worth noting at this point, that if you need to change the chain, this is a good time to do it.  I had a new chain, ready to go on, however after looking at the instructions, I discovered I would need a chain rivet breaking tool to get the old one off.  I decided at this stage I would just put the old chain back on and change it when I had the correct tools (post to follow....).
So I struggled for a while to get the rear wheel out from underneath the tail of the bike; it was a real tight fit.  I ended up having to grab the tail of the bike and lift it off the paddock stand with one arm and pull the wheel out with the other.  I'll tell you now, if you pull the wheel out on the exhaust side, it will come out easily - I learned this later when putting the wheel back on.
I then put the rear wheel on the bench and removed the sprocket, exposing the worn cush bearings.

They weren't as bad as I thought they might be, but still pretty far gone.  I discovered they were pressed in, and tried removing the rubber from one of them, to see if I could pry it out.  I spent ages chipping away at the rubber - it didn't come out easily, and the end result was that I was no further ahead.  Deciding to spend some time thinking about a way out of this, I gave the hub a bit of a clean; it was heavy with old grease, and it came out pretty nice.
I arrived at the conclusion that I would have to spin it out by force.  I soaked the bearing in WD-40, then took a large pry bar, and hammered it into the bushing.  I was then able to spin the whole bearing, and it slowly came out.  Success!

So, I decided I would make a video of the process.  I hammered the bar in, and spun out the bearing.  I then noticed that I managed to crack the casing of the hub.  Shit.

I was able to gently tap it back into place (more or less), and it seems to be okay - the bike doesn't seem all that bothered.
Here's the damage...

This shows where the prybar dented the inner lip the bushing sits in.

Here is the outside of the housing.
The lesson here is that if doing this with a pry bar and hammering it in, make sure the points of the pry bar and up against the thicker parts of the hub, not the weaker outside edge.

I then removed the other bearings, and slid the new ones in.  They needed gentle tapping to get them flush; I placed a small piece of wood on top of the bearing and hammered the wood.  This prevented me from damaging the new bearing.

I also wanted to replace the front and rear sprockets, however I could not get the cush bearing pins out of the old sprocket.  I didn't want to damage them, so I thought I'd leave them in and reinstall the old rear sprocket. I could investigate the purchase on new rear pins later.
I did replace the front sprocket, though.  This was easy - with the chain pulled off, it was two bolts holding a retainer in place, and off came the sprocket.  I did notice there was a lot of play in the sprocket on the shaft.  I wasn't sure if a new sprocket would make a difference or not.
Also, the kit I got provided a 15-tooth front sprocket instead of the original 14-tooth.  This would in theory give me a higher top speed, but would take away some acceleration as the bike would have to work harder to get the revs up.  We shall see what the end results of that are.
Installation is reverse or removal, as they say.  After putting it all back together, it was a matter of aligning the rear wheel (easy to do with the marks on the swingarm).  A quick test drive, and I noticed a difference right away - accelerating away from a stop was smoother, and steady speeds were better - not perfect though, but that's because of the old chain - it needed replacing as well.
Overall, it wasn't a terrible job - if I hadn't wasted so much time trying to figure out how to get the old bearings out, I think the job could be done in just a few hours or less.  Plus it really showed me the inner workings of the bike; there is nothing wrong with getting your hands dirty and learning how your bike works.  It gave me a chance to also check for other signs of wear and anything else that might be dangerous or might need attention soon.
I will follow up with the chain replacement process, and a report on how the sprocket change has affected drivability.