Chain tension?


Jasper-03

New member
I was riding on the highway when my chain jumped off my rear sprocket, all probally due to a way to loose chain.

In the meanwhile i have tightened my chain to a reasonable tension. But i was wondering how tight my chain should be. On the tightest part it has about 1cm space and on the loosest part it has around 3cm space.

I defenitely do not want my chain to be jumping off the sprocket again, do you guys/girls have any advice?

Thanks!:cool:

btw i have a mt-03 not a mt-07, dont burn me ;)
 

bobh

Member
According to my owner's manual for the MT-03, the chain slack should be 40-50mm, measured with the bike on the sidestand. So it sounds as if you have it too tight at the moment.

But if there's a big variation (tight spots) then it's probable that you need a new chain (and sprockets). There are various ways of checking whether the chain is worn, but the quickest and easiest is to try to lift it away from the rear sprocket - if it lifts by more than 2-3mm then it's time for a new one.

You can download the owner's manual for any recent Yamaha model free from Yamaha Owner Manuals
 

Jasper-03

New member
According to my owner's manual for the MT-03, the chain slack should be 40-50mm, measured with the bike on the sidestand. So it sounds as if you have it too tight at the moment.

But if there's a big variation (tight spots) then it's probable that you need a new chain (and sprockets). There are various ways of checking whether the chain is worn, but the quickest and easiest is to try to lift it away from the rear sprocket - if it lifts by more than 2-3mm then it's time for a new one.

You can download the owner's manual for any recent Yamaha model free from Yamaha Owner Manuals
Thanks for the reply. I had the chain on 40-50mm slack but that made the chain pop off the rear sprocket, but you're right it has a big variation.

Gonna check the chain after work tomorrow to see if im able to lift it away for more than 2-3mm, i'll let you know.
 

Ralph

New member
If the bike is new the chain does loosen a lot over the first few hindered miles but
after that keeps it's adjustment, I have never heard of any other jumping the sprocket though,
I think the adjustment is 50 mm on the side stand but what I do is adjust it so I can just make
the chain touch the rubbing strip under the swinging arm.
 

Jasper-03

New member
If the bike is new the chain does loosen a lot over the first few hindered miles but
after that keeps it's adjustment, I have never heard of any other jumping the sprocket though,
I think the adjustment is 50 mm on the side stand but what I do is adjust it so I can just make
the chain touch the rubbing strip under the swinging arm.
I had adjusted the tension so it could touch the rubber strip. But once i moved the bike 4meters forward the chain was waay tighter than it was before i moved it.

So i had to adjust the chain a little on the tighest spot, but once i rolled it back 4 meters again, the chain was considerabily more loose.

Im also hearing some strange noise coming from my front sprocket, which is strange because i never heard it before the chain jumped off my sprocket.

Im a total noob when it comes to technical stuff regarding motorcycles, but i think my rear wheel bearing might be damaged aswell.
 

Ralph

New member
That sounds like the chain or sprockets or both are damaged it must have been very loose to jump the sprocket,
could the front sprocket be loose? how many miles has it done and have you ever oiled it?
At 9000 miles mines only been adjusted twice. Can you wiggle the rear wheel sideways.
 

Jasper-03

New member
That sounds like the chain or sprockets or both are damaged it must have been very loose to jump the sprocket,
could the front sprocket be loose? how many miles has it done and have you ever oiled it?
At 9000 miles mines only been adjusted twice. Can you wiggle the rear wheel sideways.
I must admit it was very loose when it jumped off. I havent checked the front sprocket if its loose or not, i'll check that after dinner to make sure.

When i bought the bike in january this year ive ridden close to 3000 km on it, the dealer where i bought it said that the sprocket and chain were both close to new.

I drove it in the winter and always made sure that the chain was lubed with grease. Ive cleaned it thoroughly 2 weeks ago and only lubed the chain with lube out of a can from that moment on. (dont know how to call it in english).

The rear wheel does not wiggle sideways, but the holder which is inside of my wheel and which hold the rear sprocket is able to move. When i press on the left and right side it moves, but when i press on the top and bottom it does not move. I dont know if that's supposed to be or if that might be something which is not supposed to be.

Thanks for the quick reply by the way, awesome.
 

Ralph

New member
Think you mean spray can chain lube there's no movement in my rear sprocket but
I have often felt it in other bikes as the sprocket as a shock absorber built into the
hub, It sounds like the chain as tight links due to not being lubed but that is very
low miles for a chain. maybe get someone you know to have a look see what they
think mine still does not need adjusting after 5000 km I tend to brush oil on it every 2
or 3 rides.
 

Jasper-03

New member
Think you mean spray can chain lube there's no movement in my rear sprocket but
I have often felt it in other bikes as the sprocket as a shock absorber built into the
hub, It sounds like the chain as tight links due to not being lubed but that is very
low miles for a chain. maybe get someone you know to have a look see what they
think mine still does not need adjusting after 5000 km I tend to brush oil on it every 2
or 3 rides.
It might be the cush drive block, my paddock stand gets delivered this week so i'll have a look if the cush drive block seems a little worn or not.
 

Ralph

New member
If you get it on a stand you have more chance of seeing what's happening,
make sure it's stable on the stand as the shape of the swinging arm is not
good for stand use.
 

bobh

Member
If you get it on a stand you have more chance of seeing what's happening,
make sure it's stable on the stand as the shape of the swinging arm is not
good for stand use.
For the MT-03 it's a good idea to fit bobbins (M6) and use a paddock stand with hooks - much more secure.

Some Yamahas have a reputation for the front sprocket nut coming loose - I don't think the MT-03 is one of them, but it's worth checking.

One fault of the MT-03 (and other Yamaha 660 singles) is that the cush drive rubbers last no time at all - typically 5,000 miles. Then you start to feel rotational play. It's not damaging as such, but it does make the drive jerky. Also the bearing in the sprocket carrier can develop some play, which doesn't help.

One known issue with some earlier MT-03s was that the rear wheel bearings failed very quickly due to incorrect machining of the wheel and/or the internal spacer. I've had this problem on a spare wheel that I bought from ebay. There's a lot of info about this on the MT Owner's Club forum - Yamaha MT Owners Club - MT Owners Club. I don't think that would cause the chain to jump, though.

All in all, it sounds to me very much as if your chain needs to be renewed if it has such noticeable tight spots. Do you know what make and type it is? It's possible that someone has fitted a cheap one, possibly not the proper O-ring type (non-O-ring chains of this size are regularly used on off-roaders and MX bikes, where they are considered a consumable). I'd certainly fit a new front sprocket if putting on a new chain, the rear one may be OK.
 

Jasper-03

New member
For the MT-03 it's a good idea to fit bobbins (M6) and use a paddock stand with hooks - much more secure.

Some Yamahas have a reputation for the front sprocket nut coming loose - I don't think the MT-03 is one of them, but it's worth checking.

One fault of the MT-03 (and other Yamaha 660 singles) is that the cush drive rubbers last no time at all - typically 5,000 miles. Then you start to feel rotational play. It's not damaging as such, but it does make the drive jerky. Also the bearing in the sprocket carrier can develop some play, which doesn't help.

One known issue with some earlier MT-03s was that the rear wheel bearings failed very quickly due to incorrect machining of the wheel and/or the internal spacer. I've had this problem on a spare wheel that I bought from ebay. There's a lot of info about this on the MT Owner's Club forum - Yamaha MT Owners Club - MT Owners Club. I don't think that would cause the chain to jump, though.

All in all, it sounds to me very much as if your chain needs to be renewed if it has such noticeable tight spots. Do you know what make and type it is? It's possible that someone has fitted a cheap one, possibly not the proper O-ring type (non-O-ring chains of this size are regularly used on off-roaders and MX bikes, where they are considered a consumable). I'd certainly fit a new front sprocket if putting on a new chain, the rear one may be OK.
I'll definitely check the front sprocket nut, and i already ordered new cush drives. The bike does indeed feel very jerky and the cush drives are defenitely worn out.

I'll check the rear wheel bearings aswell as they might indeed be worn too. If im lucky all the parts will be delivered friday so ill be able to check it out :)

Thanks for the reply, ill let you know what i will find

Verstuurd vanaf mijn GT-I9301I met Tapatalk
 

sdrio

New member
My MT03 did about 12,000 miles before the original cush drives got sloppy, plus another 2,000 or so when I shimmed them with an old cut up rubber inner tube.

They'd only allow the sprocket to move back and forward though, which wouldn't account for a chain coming off. It could only be either the chain is loose (or god forbid the wheel is loose), or the sprockets are so worn the teeth have flattened enough for the chain to slip off them.

Something ain't right!

Bear in mind, if you have a damaged sprocket, you really need to replace both of them, and the chain. They will have all worn together, and if you replace any single component, the other worn ones will tear it to pieces in double quick time.
 

Jasper-03

New member
My MT03 did about 12,000 miles before the original cush drives got sloppy, plus another 2,000 or so when I shimmed them with an old cut up rubber inner tube.

They'd only allow the sprocket to move back and forward though, which wouldn't account for a chain coming off. It could only be either the chain is loose (or god forbid the wheel is loose), or the sprockets are so worn the teeth have flattened enough for the chain to slip off them.

Something ain't right!

Bear in mind, if you have a damaged sprocket, you really need to replace both of them, and the chain. They will have all worn together, and if you replace any single component, the other worn ones will tear it to pieces in double quick time.
I wasn't even riding fast, it might have been the bump in combination with a loose chain and a ton of bad luck.

The sprocket and chain was supposed to be new (thats what the dealer told me), and by looking at it the sprocket its teeth are not really worn, but im a total noob, so i could be wrong of course.

I'm also noticing more vibration than normal, and it feels like its coming from my front sprocket. Once i get my parts i'll get the rear wheel off and i'll have a look at the cush drives and the bearing. I might even have to buy a whole new chain and sprocket i suppose.
 

Jasper-03

New member
Yesterday i checked the tension of my chain by pulling it on the end of the sprocket. The chain is waaaay to loose.

So i ordered a new chain+sprockets, i should be getting them saturday so i'll let you guys know if the bike runs smoother after replacing the:

- Chain
- Front sprocket
- Rear sprocket
- Cush drives

Lets hope it does
 

Jasper-03

New member
I couldnt wait for my parts to arrive. So i took my rear wheel off to inspect my cush drives. The previous owner had already put in little pieces of innertube inbetween the cush drives.

So it was already worn when i bought it 3000km ago. I replaced the innertube with fresh pieces and a little extra, just to make it snug.

The bike now drives way smoother already. Its just a temporary solution, just so i can ride smoother untill i get my parts.

Verstuurd vanaf mijn GT-I9301I met Tapatalk
 

Jasper-03

New member
I just got done replacing the chain, front & rear sprocket ánd the cush drives. And the bike drives like a charm! The front sprocket was very worn and the chain aswell.

I made some pictures in the process to let you guys know what the sprocket looked like.

The only problem i still have is that the front sprocket makes a continues whining-like noise. I have no idea what it might be, does somebody know? Here are some pictures of the sprocket & more:



 


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