Important disclaimer:
I did not need to do this. The weather is nice right now, the chain was in good condition, the sprockets were in good condition. I did this because I had time, the conditions were fortunate, and I was about to start working again so I was about to no longer have free time anymore. I wanted to learn this while I still had the flexibility of f**king up, waiting for parts to be shipped to me, then fixing it. I'd also never changed a motorcycle O-Ring chain myself, despite having changed and cut hundreds of bicycle chains.
There's no reason to swap your chain this early other than you want to do it.
I f**ked up, and had to take two swings at this so I'm glad I did this when I was actually able to get replacement parts.
Additionally, the Motion Pro Master Link Press Tool P/N 08-0675
did not work on the 428 chain as the tool was intended to be used. (Advertisers note: they never said that it would work, but the advertising material also indicated there was nothing stopping it from working either and that it should work) I'll be manufacturing my own version of this tool in the near future because I was able to get it work (not in the way they intended me to use it), and it was actually useful in the end, but it'd be way better if I could use it the way they think it should work.
Task: Swap out the chain and sprockets for the DID 428 VX X-link chain.
Time taken: 1h of actual work. Probably 10 minutes to replace the front sprocket and 10 minutes to replace the rear sprocket. Successfully installing the X-link chain took around 10 minutes, but a lot longer when I couldn't get the outer plate pressed in enough and eventually broke the master link. Most of the time was spent aligning the chain and getting the chain tension right, a step worth taking your time on.
Odometer: 2296 mi
CT125A manual specification:
3-14 Drive Sprocket Cover
2-33 Engine Unit (front sprocket)
3-26 & 3-27 Rear Wheel
Fiche references:
Important parts interacted with:
- DID 428 VX Chain, +1 extra Master Link coz I f**ked up and forced on the clip for the previous one.
- SPROCKET, DRIVE (14T) - P/N 23801-K2E-T00
- BOLT, HEX. (6X10) - P/N 92101-06010-0A
- SPROCKET, FINAL DRIVEN (39T) - P/N 41200-K2E-T00 - see note under front sprocket replacement
How the bike felt: Good
How the bike felt after: Same, maybe better.
Tools:
- (Suggested) a long piece of cardboard to lay on the ground
- (Suggested) a sharpie
- (Recommended) Straight edge ruler with mm gradations, 12" is best, gradations starting from the very end of the ruler is best. Calipers with a depth measurement capability will also work.
- (NOT Recommended) Motion Pro Master Link Press Tool P/N 08-0675 - equivalent would be good, but something that actually fits the 428 chain.
- Replacement 428 chain. Honda Manual states for stock configuration it is 108 links.
- (Optional) Dremel tool with wheel to grind down or cut the head off the riveted pin.
- Chain breaker - I used this one: HIFROM New Chain Breaker Cut Link Remove Tool Compatible with Motorcycle Bike ATV Heavy Duty Chains 415 420 428 520 525 530 630,Chain Breaker Link Splitter Tool - $15
- Socket wrench
- 19mm socket (rear axle nut)
- 14mm socket (chain breaker)
- 8mm socket (front sprocket cover)
- 14mm wrench (rear axle bolt)
- 12mm open ended wrench (chain adjustment)
- 10mm open ended wrench (chain adjustment)
- (optional) extra Master Link
For replacing the sprockets:
- (optional) Motion Pro Chain Alignment Tool P/N 08-0048
- Torque wrench (59 Nm max, 12 Nm min)
- 14mm wrench (rear axle bolt)
- 19mm socket (rear axle nut)
- 8mm socket (front sprocket cover, rear sprocket nuts)
- 10mm socket (front sprocket nuts) - thin wall sockets or something like the Motion Pro 08-0145 T-Handle Deep Socket Set
- Blue loctite
Torque specs:
- 6mm Hex bolt nominal torque: 12 Nm
- 14/19mm Rear Axle: 59 Nm
- Honda Nut attaching rear sprocket to hub: 32 Nm
Videos:
For only replacing the chain, there's two methods for this. The first is the same as the chain and countershaft sprocket - front cover comes off, expose the chain, then pull it through and manually feed it. The second is to use the old master link, pull the old chain through by connecting the master link to the new chain (without the clip) and making one super long, 216 link chain, then feeding it though. I used both, because I had to do two attempts at this.
- For both methods, the recommended start point is to take a photo of the master link clip orientation so you know you installed it the correct way and lay out a long piece of cardboard or newspapers (the chain will be placed down on this). I taped two Amazon boxes together.
- You also will want to pop off the front countersprocket cover. This requires a 8mm socket to undo two bolts.
- Using the feed-with-master-link method on an uncut new chain means either counting the links, or marking it and feeding the new chain through twice - once to measure it, once to take it off to cut the chain (feeding the old chain back on), then once to actually install it. I feed it through twice. This is also useful if you are fitting new sprockets of a different size.
There are a lot of videos and every chain and chain tool is different. Sometimes you'll need to Dremel, sometimes you can just use the tool and pop out the link. Familiarize yourself with this step before proceeding.
I did this in the following order:
- Remove rear wheel and replace rear sprocket.
- Replace front sprocket.
- Reinstall wheel.
- Replace chain (easiest to use the rear sprocket to hold the chain)
- Align and adjust everything once everything was installed.
To remove the old chain:
1. Either pop the master link clip off, or press out a rivet using you preferred chain breaking technique.
2. Pull the old chain off. Do not throw it away yet.
To cut the new chain to the same length
3. Place the old chain on the piece of cardboard you've laid out ahead of time.
4. Place the new chain next to the old one. If it's worn the old chain will be a fair bit longer than the new one. Line up the start of the chain, and then line up the end of the chain link-for-link (so you have the same number of links). Place your chainbreaker near the end of the old chain with the shaft open far enough to slide the link in.
5. After double checking which pin to remove, use a sharpie to mark the pin that is being removed. You might need to clean the outer plate and rivet slightly of grease.
6. Take your chain breaker and pop out the marked rivet.
I did not need to dremel mine using the tool I used.
7. Your old chain was likely longer than the new one. It will be a good idea to loosen the rear axle, and undo the locking nut on both sides of the swingarm adjusters so you can easily put the chain back on.
To install the new chain
8. Feed the chain through the sprockets, counter sprocket and rear sprocket.
9. Line up the links that you're going to pin together on the underside of the rear sprocket. Why there? Because it'll space them correctly and make it easier to put the master link on.
10. Feed the master link on so the open side is facing you. Follow the instructions on the packet - if it says use grease, use grease. If it says put some rings on first, put those on first. Etc.
11. Press the outer plate on. The outer plate should be far enough on that the master link clip can easily slide into the grooves, and does not need to be forced in.
Depending on the replacement chain, this step might be easy or difficult. The non-sealed DID 428 chains went on without any tools. The X-Link chain required a press. Something like the Master Link Press Tool can do the trick - a C-Clamp and a nut, two vise grips, etc. although they do tell you not to use vise grips, that's what most people seem to use.
12. Look at the photo you took before you started to check master link orientation - where the open end is and where the closed end is. Using pliers and one of the pins, slide the master link clip into the groove. This should not require much effort. If it's hard, the outer plate probably was not pressed in far enough, so press it in more and repeat. (note on the pliers: you can make your own master link pliers pretty easily for very cheap)
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