welding sprocket on **pic added***

[BigGeeking]

Right guys
Look like I have some ware on my drive shaft splines going to my front sprocket
Its only a cg125 that I paid less than 500 for I had a look in to a new counter shaft and gaskets ect ect and its just too much.

I’m going to keep the bike till its dead or for another 2 years till I am not under the 33bhp licence.

Its about half way throw the splines don’t know how long its been like that for as its 10th hand
Or something stupid like that

Any way I was going to weld it on I have a arc welder and I was going to keep the locking plate on and weld it on keeping it strait as pos

And it has new chain and sprockets on that’s how I found out the shaft is getting goosed.

Any ideas.

____________________
Bendy "Flip front. I can filter down the M4 while shoving a Twix in my face."
honda CG 125 2001 SOLD-- current Bandit 400--SOLD. current SV650s 2000
MOD 1 ON 20/7/2011**passed** MOD 2 ON 17/10/2011***passed***,,

[jimbothe]

I wouldn't weld it. I think you're asking for more trouble. Welding creates heat, a LOT of it. You will melt any seals nearby or connected to the shaft and probably end up with some bad leaks.

Can you post a picture?

If it's that bad that you have to try and weld it on straight then I would say it's very badly worn

Can you not try cleaning up the splines with a small file?
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[thomp1983]

you sure it's not just a normal amount of play? most bikes have what seems like an unusual amount of wobble in them but are usually fine

chris

[BigGeeking]

i'll try and get a pic.

could i put the sprocket furthere down the shaft if the chain dose not fowle any where
____________________
Bendy "Flip front. I can filter down the M4 while shoving a Twix in my face."
honda CG 125 2001 SOLD-- current Bandit 400--SOLD. current SV650s 2000
MOD 1 ON 20/7/2011**passed** MOD 2 ON 17/10/2011***passed***,,

[BigGeeking]

[quote=

Can you not try cleaning up the splines with a small file?[/quote]

what do you mean mate
____________________
Bendy "Flip front. I can filter down the M4 while shoving a Twix in my face."
honda CG 125 2001 SOLD-- current Bandit 400--SOLD. current SV650s 2000
MOD 1 ON 20/7/2011**passed** MOD 2 ON 17/10/2011***passed***,,

[jimbothe]

I mean check the splines on the shaft and try and file lightly in-between the splines if there is any burring of the splines.

This thread is pretty hard to comment on without a picture. If you do get the chance then post back with one if you can as we could all be giving the wrong advice based on a lack of visual knowledge.

I fail to see how the spline has worn away on a 125 unless the sprocket was incorrectly fitted or the wrong one.
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[chrisjpartrid...]

It's a bad plan - I've done this before on a scrap bike and it worked... but not that well.

You'll melt the seal behind it so gain an oil leak and it's worth noting that a little play is normal.

[Pete.]

Splines wear from neglected chains. Particles of metal from the chain get into the splines and act like grinding paste.

You have your new sprocket, and it fits on the spline. Okay so it might be loose but that's not a huge problem. Have no doubt it will have to be very very worn to shear off the last bit of spline so that the sprocket is rotating.

Does the reatiner still work? If so I would grease the spline up, fit the sprocket and forget about it. The grease will reduce the wear rate hugely. If the retainer is not working due to the wear I would fit the sprocket on the shaft, then put a large washer over the spline then lightly weld the washer to the spline but NOT weld the sprocket itself to the spline at all. All you need is a couple of small tacks such as can be removed with a grinder for changing the sprocket later if ever needs be. Then whilest it's hot get some grease on it so that it runs into the spline.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[cb1rocket]

there should be side to side play and the retainer do wear out so is worth getting a new one. Pics would help

[Teflon-Mike]

THE PROBLEM... as described sounds like culmulative effect of poor chain care and hard life. Tight chain, slack chain, lots of load changing clumsy changes, poor cleaning, lack of lube etc.

Sprocket, the bit that wears is 'soft' steel, shaft is hardened steel, so NORMALLY sprocket would take the knocks and splines on shaft would survive OK.

So I'm with others on this one.

Sprocket isn't rigidly bolted or welded to the shaft for a reason.
some 'play' is there to help the sprocket & chain 'self align'.
Attaching it rigidly to the shaft, it would have to be aligned MORE accurately than thee designer COULDN'T get it to rear sprocket, and would have to be realigned every time you adjusted the chain tension, or you would have problem of misalignment increasing chain / sprocket wear.

First up; given soft sprox, hard shaft, IS the shaft REALLY that bad?

Next up; whats the oragin of the 'new' sprox? are thy chap chitty things with lots of slop to start with?

Real 'fix', IF its the shaft is to make that bit 'good'.

Most obviouse 'propper' fix would b to pull motor apart, split cases and replace output shaft. Its a CG.... scary BUT its NOT actually THAT hard to do.

But whats cost/avail of new or good second hand shaft?

If inordinatly expensive or unavailable; old fassioned salvage would be to 'rebuild' the splins on shaft you have.....

Couple of M/C shop ways to do that, on would be to turn down the splined section of shaft in a lathe, then shrink fit a new splined sleeve over it.

Altrnatively, splined section could be 'welded over' then the splines re-cut into the new metal.

BUT.... onto bodges... a 'bodge' is any 'improvisd repair' that cost more or makes more work than doing it properly to begin with....

So, improvised repair.... Cable ties pushed through gaps in sprok to take up clerance? Glue? What do you thing is more or less likely to work well?

But getting CANNY.... my reccomend, as you already SUGGEST moving sprox furhther inboard on shaft would find good spline...

CG sprox are £5 a piece... if you dont have the old one, or its splines are 'duff'.....

Angry grinder... grind it down to remove teeth, to leave you splined disc. take it a good 2mm or more smaller than the bottom of the valleys between teeth...

Now, slide THAT onto shaft behind sprok.... to make 'wide' base sprok, joining disc and sprok together.

If you WANT and can do it accuratly nough, could weld disc and sprok togethr, but I'd simply drill the retainer plat scrw holes 'through' the toothd sprok, then use long bolts to sandwich toothed sprok between retainer plat and ground down sprok.

No welding..... no melted seals..... no engine strip... no bodges..... one £5 sprokt and two 10p M6 scrws TOPS....... job jobbed, neatly, and reliably..... AND you could still change sprokets AND retain the self alignment 'wobble' etc.....

Worth a shot before reaching for the stick metal sticker?
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[Robby]

In circumstances like this- where I assume the splines are worn down but totally worn out - there are a few options I can think of.

1. Weld the sprocket on. Quick and dirty, and you'll only have the life of the sprocket until the engine is effectively scrap. Not a good idea, but on a worthless bike that may be scrap in 10k miles anyway, maybe not the end of the world. If you were going to do this then the important things would be to really clean up the area to be welded, and to only do the mininal amount of welding required. A few tack welds will hold it, and could be ground off to replace the sprocket.

2. Build up the sprocket with weld to fit the knackered splines better. The splines have worn down, so the standard sprocket isn't going to grip too well. Building up the contact faces of the sprocket with weld and then dressing it back to the correct shape with a file would give you a better fitting sprocket.

Do not, however, try to do one continuous seam weld all around the shaft onto the sprocket. The heat will kill seals, and the sprocket will never be removed.

CG125 engines are cheap and easy to swap out.

[CarlosCBR]

If you weld the sprocket on, what you going to do when that one wears out and you need a new one?
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[Pete.]

[Frost]

[iooi]

Ever heard of paragraph's

[BigGeeking]

thanks for all the replayed peeps as soon as i get a link lead for the cam i'll post a pick.
i hope it is normal but i cant see it
____________________
Bendy "Flip front. I can filter down the M4 while shoving a Twix in my face."
honda CG 125 2001 SOLD-- current Bandit 400--SOLD. current SV650s 2000
MOD 1 ON 20/7/2011**passed** MOD 2 ON 17/10/2011***passed***,,

[SoND]

[BigGeeking]

pics
____________________
Bendy "Flip front. I can filter down the M4 while shoving a Twix in my face."
honda CG 125 2001 SOLD-- current Bandit 400--SOLD. current SV650s 2000
MOD 1 ON 20/7/2011**passed** MOD 2 ON 17/10/2011***passed***,,

[SoND]

Splines are bigger than I thought.

Araldite steel epoxy will probably work, build it up and file it down. Make sure the shaft is absolutely free of all grease, oils and water before you use it.

https://www.npmanek.com/SubProd_AralditeSteelEpoxy.aspx
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[Vincent]

Sorry mate, that shaft needs replacing. Might be the result of someone trying to wheelie by dropping the clutch - over and over.
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[Pete.]

It's pretty worn but I'd fit the sprocket and ride it. Use grease. It'll be moving about but if it's greased the wear will be low. no point speculating how long it will last, all you can do is give it a few days and check, then if it's no worse check again weekly.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Vincent]

Might be worth putting the sprocket on, turning it as far to the right, (clockwise), as it will go then smothering it with silicon RTV so that it doesn't move about as much. Not sure it will work, but worth a try perhaps.
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[Pete.]

Not a bad idea but I think that torque reversal would soon see RTV off.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Vincent]

[Vincent]

Coming back to the OPs problem - how about drilling and tapping a couple of holes in the sprocket then using grub screws to secure it to the shaft?
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