Chain & Sprocket vs

[Guest]

As I am new to biking and owning a Yamaha ybr 125 custom ( love the bike ) my question is people talk about changing their chain and sprockets, is there a set amount of mileage that they should be changed, like the timing belt on a car ,or is there something I should be looking out for.Thanks all.

[GazW]

A badly maintained chain and sprocket will be knackered in a few thousand miles.

Correctly maintained, adjusted, cleaned and lubricated it should last a lot longer.

It will need replacing either when it's shagged, or when it reaches the end of its adjustment.

I personally haven't ever had to replace a chain due to it reaching the end of its adjustment, but I've also never seen a chain through its entire life on a bike. I've always bought a bike with a partially worn chain, replaced it, and sold the bike before the one I put on has worn. It's not intentional, it's just how it's fallen.

[Bonniebird]

The chain should be oiled regularly and the tension checked and adjusted periodically. Generally it gets slacker as it gradually stretches and the tension is increased by loosening the back wheel nut and then adjusting the small screws to move the wheel backwards slightly, increasing the tension. The sprockets wear over time too so should also be checked or the chain could slip. If the chain is well adjusted,clean and oiled then it and the sprockets will last a lot longer.

The length of time it will last will vary depending on the bike, riding, mileage, quality of the chain and how well it is looked after and kept rust free.

The less robust chains on a 125 will probably not last as long but hard to say as it is not propelling a 200kg bike with a 1000cc engine

[fq-craigus]

A decent brand of chain will offer a sensible warranty, like my did, it has a 15k gaurentee (as long as maintained correctly) a cheap chain will nacker up no matter what you do.

Keep it clean, keep it lubed, keep it adjusted.

[marksmith]

Possibly worth reading a bit about how to check the chain too. How will you know it's knackered (before it snaps or ruins the gearbox bearings)?

Here's my brief version, but I'd encourage you to read up a bit, I'm no expert, just a person with a bike.

The "stretch" in the chain is due to the links wearing - the holes elongate a tiny bit. This doesn't always happen evenly, and you might find that 99 of the links are fine and one is stretched. This stretched one won't sit properly on either sprocket, and you'll end up with a "tight spot", meaning the (otherwise correctly-tensioned) chain is too tight when in a particular position. You need to do at least one full rotation of the chain, checking tensions every 10cm or so. Only if the tension is acceptable in all chain positions, is the chain good.

Hope that helps!

[banditjohn]

And don't forget to always adjust it with the weight of the bike on the rear wheel (side stand or paddock stand), as the others have said the mileage depends on how you ride and maintain it, I get 15-20 k miles out of mine but the argument against the shaft drive will remain as the maintenance is minimal (not that i'd know it's been years since I has a shaft drive bike)