Sprocket Gonzo

[Sand bags]

Back again.

Unfortunately my previpus post for this problem got deleted in the crash.

Recap:

Went to leave work, drove round the corner and got stranded at the lights. Bike went into gear but just revved away going nowhere. Pulled over, saw that the chain was slack, but still on the back sprocket. There is a panel covering the front panel and it was dark so I couldn't see. I snapped some pics and wheeled it back to work and got the train home.

The pics:

Didn't realise this but a friendly user from this forum pointed out that you can actually see the sprocket popped off in this picture.

Unfortunately the sprocket must have fallen off whilst I rolled it back to work. Come back to work with some tools and just removed the panel to see no sprocket pics:

 

So I'll have to order a sprocket replacement (maybe a whole chain and sprocket kit).

I was wondering, how is the front sprocket secured once it's slotted into position? I can't see any threads or anything, please advise.

Also, to adjust the chain, would I just need to undo the main nut on the back wheel, and adjust using the other chrome bolt sticking out, if that made sense...

 

Thanks

(Forgot to mention I am new to motorcycles and this is my first owned bike. Sorry for any stupid questions that may seem obvious, still learning!)

[TimR]

there will be a slotted washer that sits in the groove on the shaft and is locked in place by offsetting the splines on it and this then bolts onto the sproket ....

[fastbob]

Tim has it spot on but It's probably worth mentioning that a sprocket attached in this way is supposed to be free to wobble around a bit . So don't be too worried if it isn't rock solid when fitted. I'm guessing its a Zontez you have so here is the sprocket.https://www.ebay.co.uk/p/Front-Sprocket-15t-for-Zontes-Tiger-Zt125-3a/570499592

[Bender]

I would go with sprockets and chain then you know it's all good.

[Sand bags]

Thanks guys.

Is it likely that this slotted washer comes with the sprockets, or is it a separate purchase.

I'll email the seller and ask.

And thanks for the tip lol I definitely would have been questioning any wobbly movement!

[fastbob]

Thanks guys.

Is it likely that this slotted washer comes with the sprockets, or is it a separate purchase.

I'll email the seller and ask.

And thanks for the tip lol I definitely would have been questioning any wobbly movement!

 

The washer won't come with a chain and sprocket kit .

[Via]

Also, to adjust the chain, would I just need to undo the main nut on the back wheel, and adjust using the other chrome bolt sticking out, if that made sense..

 

Yes, but just to point out the obvious 'just in case'... There will be another one on the other side of swing arm, both need to be adjusted together (normally marks on swing arm to match both), otherwise you'll end up with a wonky wheel.

[JRH]

as Via says

With noting that there is a lock nut on the adjusters that needs loosening.

So my order of operation is

Undo axel bolts

Undo locknuts.

Turn the adjusters 1 flat at a time on each side.

Check chain tension.

Repeat as necessary

When tension correct

Tighten locknuts tighten axel to correct torque

Recheck tension

If ok all is good if not redo as above

HTH

[TimR]

if you have the owners manual it will explain chain tensioning also

[Sand bags]

as Via says

With noting that there is a lock nut on the adjusters that needs loosening.

So my order of operation is

Undo axel bolts

Undo locknuts.

Turn the adjusters 1 flat at a time on each side.

Check chain tension.

Repeat as necessary

When tension correct

Tighten locknuts tighten axel to correct torque

Recheck tension

If ok all is good if not redo as above

HTH

 

Lovely mate, thanks for breaking it down.

 

Also, to adjust the chain, would I just need to undo the main nut on the back wheel, and adjust using the other chrome bolt sticking out, if that made sense..

 

Yes, but just to point out the obvious 'just in case'... There will be another one on the other side of swing arm, both need to be adjusted together (normally marks on swing arm to match both), otherwise you'll end up with a wonky wheel.

 

cheers mate, feel free to point out the obvious anytime with me lol could always do without a wonky wheel.

 

if you have the owners manual it will explain chain tensioning also

 

Unfortunately it didn't come with a manual, and they seem to be like gold dust for this bike lol

[Sand bags]

Having a look and found two sprockets for the zontes on eBay.

One is 15t, which I assume is the original, and the other is a 17t upgrade. I'll probably stick to the original, but out of curiosity how would more teeth benefit?

Im having trouble trying to find the bracket/retainer for the sprocket. There aren't any listed for the zontes, so I am unsure which size to go for. Tried contacting a Zontes dealer, waiting on a response..

[Mississippi Bullfrog]

A larger front sprocket would raise your gear ratio which on paper might seem to give you a higher maximum speed, but in reality usually reduces top speed because smaller engines don't have the torque at lower speeds.

Many 125 owners put a smaller front cog on, down one tooth, and find they can hold better speed in top gear.

[exportmanuk]

Hi Looking at the pictures the side of the engine gearbox where the output shaft is looks very clean normally this is covered in oil and grease thrown from the chain so it is probable the chain had been dry for a long time so I would replace it too if you can afford it. if not soak it in chain oil for a few days then clean it off and oil it again before re fitting

[fastbob]

Hi Looking at the pictures the side of the engine gearbox where the output shaft is looks very clean normally this is covered in oil and grease thrown from the chain so it is probable the chain had been dry for a long time so I would replace it too if you can afford it. if not soak it in chain oil for a few days then clean it off and oil it again before re fitting

 

Well observed , its dry as a desert in there . The chain looks straight out of the box but even a new chain needs lubrication . Presumably the person who recently fitted this chain was incapable of adequately tightening two bolts . One falling out is unfortunate but to lose another is just careless. Probably a good idea for the owner to check the rear sprocket and anything else this monkey has waved a spanner at.

[Sand bags]

Hi Looking at the pictures the side of the engine gearbox where the output shaft is looks very clean normally this is covered in oil and grease thrown from the chain so it is probable the chain had been dry for a long time so I would replace it too if you can afford it. if not soak it in chain oil for a few days then clean it off and oil it again before re fitting

 

Thanks. Yea I checked the condition of the chain and rear sprocket and they seem good. I will definitely clean and re-oil as you suggested.

 

Hi Looking at the pictures the side of the engine gearbox where the output shaft is looks very clean normally this is covered in oil and grease thrown from the chain so it is probable the chain had been dry for a long time so I would replace it too if you can afford it. if not soak it in chain oil for a few days then clean it off and oil it again before re fitting

 

Well observed , its dry as a desert in there . The chain looks straight out of the box but even a new chain needs lubrication . Presumably the person who recently fitted this chain was incapable of adequately tightening two bolts . One falling out is unfortunate but to lose another is just careless. Probably a good idea for the owner to check the rear sprocket and anything else this monkey has waved a spanner at.

 

Haha, yea I will give the rest a looking over.

What are the list of nuts that should be part of my regular checks or tightening?

Also, I think I'm going to get a torque wrench. As I mentioned before I can't find the manual or much info on the zontes tiger, but are the rear wheel bolts generally tightened to 100nm? I think that's what I recall seeing for other bikes...or does it differ quite a bit for different bikes.

Cheers

Thanks

[fastbob]

You really don't need a torque wrench for stuff like this . They are more geared towards engine building where precise amounts of torque are specified . For something like a wheel nut , just give it a good hard yank with a ratchet . All you are trying to do here is stop it undoing.

[TimR]

You really don't need a torque wrench for stuff like this . They are more geared towards engine building where precise amounts of torque are specified . For something like a wheel nut , just give it a good hard yank with a ratchet . All you are trying to do here is stop it undoing.

 

To someone with experience a torque wrench is not essential but to someone with limited or no experience i would think a torque wrench would be beneficial .

especially on things that if loose can cause stability issues like axle nuts .

[fastbob]

You really don't need a torque wrench for stuff like this . They are more geared towards engine building where precise amounts of torque are specified . For something like a wheel nut , just give it a good hard yank with a ratchet . All you are trying to do here is stop it undoing.

 

To someone with experience a torque wrench is not essential but to someone with limited or no experience i would think a torque wrench would be beneficial .

especially on things that if loose can cause stability issues like axle nuts .

A torque wrench can also be a dangerous tool in the wrong hands that could easily lead to stripped threads especially if they are already worn,damaged or greasy .There is no substitute for " Touch" and that is the only way that experience can be gained .

[Gerontious]

Also, I think I'm going to get a torque wrench

 

 

Good Idea.. always worth having one while you build experience. I know a highly experienced mechanic who uses one on every bike that he services. I asked him once, why?

"Because Im not stupid - this isn't my Bike."

Good answer. The problem with people telling you to do what they choose to do.. especially when its not in line with the manufacturers advice, is, They wont be there to help you pick up the pieces if or when it all goes horribly wrong. Its not their bike. its not their wallet.

As you gain experience then you can do things 'your way'... but in the meantime?

Better safe than sorry. A torque wrench isn't an expensive piece of kit.

And thats all i have to say about this particular question.

[exportmanuk]

Better safe than sorry. A torque wrench isn't an expensive piece of kit.

 

 

Hi Don't disagree but personally I only use them on engines and the like. What I will say is don't buy a cheap one and learn how to use it before using it in anger. A torque wrench will not stop you for over tightening the piece if you dont use it correctly.

[skyrider]

You really don't need a torque wrench for stuff like this . They are more geared towards engine building where precise amounts of torque are specified . For something like a wheel nut , just give it a good hard yank with a ratchet . All you are trying to do here is stop it undoing.

 

To someone with experience a torque wrench is not essential but to someone with limited or no experience i would think a torque wrench would be beneficial .

especially on things that if loose can cause stability issues like axle nuts .

A torque wrench can also be a dangerous tool in the wrong hands that could easily lead to stripped threads especially if they are already worn,damaged or greasy .There is no substitute for " Touch" and that is the only way that experience can be gained .

a few years ago i bought a yam as3 125 and i decided to change the plugs after much struggling with the plug spanner i attached a short length of car exhaust pipe to the spanner and hoped like hell that the plugs wouldnt break off in the cylinder heads anyway they didnt and they finally came out, which gorilla put them in god knows but those sort of people shouldnt be left alone with tools in a workshop

[Sand bags]

Yea, well up until now I have just been tightening it by judgement. So e.g. spark plugs im cautious not to over do, but other heavy duty nuts/bolts I'll give a good yank on. I thought about the torque wrench because I watched a short tutorial on replacing chains and the guy used torque wrench for the rear wheel nuts.

As some of you have pointed out, seems a useful bit of kit to have, but I suppose it's only useful if you have the right info on how tight each section has to be, otherwise it goes back to guess work.

I've ordered the sprocket btw, hopefully be with me in the next couple of days, and I've ordered chain cleaner and lube. Should be able to just fix it at work and drive back. Hopefully goes all smoothly lol

[Sand bags]

Little update for those Interested. I ordered the sprocket and retainer bracket and installed it at work. Also cleaned, lubed and adjusted the chain. Drove it home no issues, all seems well!

As I didn't have a manual, I adjusted the slack for about 30mm (what seemed to be the average measurement for other bikes on forums). Once I tightened it all Bolts it actually ended up a bit below 30mm.

I planned to recheck it all today on my day off so I can take some more time and recheck nuts all around the bike, and luckily I noticed that it has the slack measurement written on the chain guard... 15mm. So I will re-adjust to this.

Also tip for anyone else with zontes tiger in same position. When I was searching for parts I could only find the sprocket on its own (no bolts no retainer bracket). It worked out alot cheaper and easier buying a front sprocket kit for a 125 pitbike (sprocket, 2xbolts and retainer bracket included) for £6! Just had to make sure it was the same type, which is 428 15t 20mm. Took about 5mins to install, straight on no problem.

 

 

Thanks to everyone for the advice. Learned a lot.

[learningtofly]

Nice job, and an interesting thread to follow!

[fastbob]

Excellent job ! Sounds like you're shooting up the learning curve and gaining confidence along the way . Great to see a follow up post too .