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Discussion Starter · #1 ·
Fitting a chain (original Meriden, 3,000 miles use) to another hub.

The rear sprocket has some wear. It's possible the sprocket is original, wheel is flawless, just about.

Worth replacing sprocket? About £40 for a decent one.

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Discussion Starter · #3 ·
Ok, thanks. Knew the test, thought that was for chain though.

If you think it's worn, that's good enough for me. To avoid any general misunderstanding, I'm saying your word's good enough, not the sprocket.

I have a running bike with thousands of miles on similar conical sprocket. No visible wear. So might indeed prise the wallet open...
 

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Want to say chain is 20-25mm slack, but if your replacing the chain an aftermarket one would be a nice swap as well. It does look well worn but not dangerous , see a little curve or chip on a tooth, them your getting dangerous. I'd replace it with a slightly larger sprocket maybe +3teeth. Getting to the point for a new chain and sprockets as well. My rides may be a little more enthusiastic then an average Triumph. Maybe a Yamaha 900XSR will be a good supplement bike and I can give my bike some rest and easy riding.
🍔
 

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Discussion Starter · #5 ·
Thanks burger. I'll have to flip you 😃

It'd go one tooth less, not more. But not to be had with the conical. I've got a larger (19") rear wheel though.

Won't be buying a Yahaha though, I'll just buy the sprocket. More economical.
 

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I would change that one. My sprockets get very little wear as i lubricate every ride. I have just worn out a chain after about 10,000 miles. Kept the sprockets on when fitting the new chain. Front sprocket has about 20,000 miles so far.
 

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1976 Triumph T140V and 2002 Triumph Thunderbird 900
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Thanks burger. I'll have to flip you 😃

It'd go one tooth less, not more. But not to be had with the conical. I've got a larger (19") rear wheel though.

Won't be buying a Yahaha though, I'll just buy the sprocket. More economical.
On my 1976 T140V I’ve gone from 47 teeth down to 43 teeth on my rear sprocket and it suits me down to the ground, I no longer feel that my bikes over reving and not wanting an extra gear.

John.
 

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When my T140 was my everyday bike, I replaced the chain every 6000m and the sprocket set every third chain / 18000m. Chains were cheap and were well knackered by 6000m. And by 18000 the gearbox sprocket was well past its best.
 

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Hi,
larger (19") rear wheel
Irrelevant on its own, depends on the tyre fitted. Nearly all triples were fitted with a 19" rear wheel, with a 4.10 tyre; those that weren't (Hurricanes) were fitted with an 18" wheel and 4.00 tyre, same as your twin. Same OD.

As @rambo has intimated, the trick to long rear chain life is lubrication. I've used Scottoilers since the early 1990's, the longest-lived chain has now covered some 15K miles (first ~10K every day in all weathers) and is about half-way along the swinging-arm adjusters. I've yet to replace a Scottoiler-lubed rear chain or sprockets.

Another nice thing about Scottoiler-lubed rear chains (all auto-lubed rear chains?) is no concern about lubing after a ride if you don't feel like it, it's lubed already (y) and it'll still be lubed when you want to use the bike next, whether it's minutes or months later.

Hth.

Regards,
 

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I used to have a pillion on most rides but not so often now as my wife is 70 years old. Combined weight was 360 lb so the chain worked hard. I regularly check my chain rollers. Chain tensioning as required but not too often it needs doing. My recent chain change showed a fair bit of stretch. Never had a chain snap but this is down to maintenance and replacement when mileage is fairly high.
We do use the T120r on the Dartmoor rides and she comes along and enjoys it although, it nearly always rains !
Age has meant no long rides now but we had a lot of fun getting old on these bikes.
 

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I knew someone who wasnt 'mechanically sympathetic' and caned his TR7. Neither was he able to maintain his bike, and always needed help.

Story went round that his chain had stretched to the maximum range on the wheel adjustment, and someone had cut out a link and moved the wheel back into adjustment range.

Next story was that he had broken the chain.

Then he turned up at my place asking if I could fix an oil leak from the back of the engine. Taking the primary cover off revealed a big hole where the end of the breaking chain had wrecked the back of the crankcase.

Hence I was always careful with chain wear / stretch on my bike.
 

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I learned years ago to check your chain at times to test for stretch on the sprocket. Once the chain becomes stretched it rides toward the tops of the teeth and wears out the sprockets. Replace the chain before that happens and the sprockets last for several chains. I also lube my chains often with white lithium grease. Just a light spray on about 6" of chain every few times out and you have the necessary lube but it won't be flying everywhere.
 

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I was on a long ride [2000km] through some remote country with another Trident owner when he busted his clutch cable. No probs, he replaced it with the spare he was carrying. The handlebar nipple almost immediately separated on this one as well and the nipple was lost. At this stage in my riding career i didn't carry a spare clutch cable. So the guy had to continue riding without a cable. This would have been ok except that his rear sprocket and his chain were also near or at their 'used by' date. So every time we went through a town or he had to change gears the chain would spin off the rear sprocket. So we would stop, drag the tools out, loosen the rear wheel, and put the chain back on the sprocket. Then I'd push him down the road and he would snick it into 2nd and ease open the throttle and away we would go.
We got to the bike meet ok, but the next day and the trip home was the stuff of nightmares. We left early, but didn't get home to my place till the early hours of the next morning...I lost count of the number of times we loosened the rear wheel and redid the chain esp. in the dark on the side of a lonely country road. Of cause the sprocket got worse, the chain was stuffed, and our knuckles had no skin left on them.
The lesson here is...always keep your chain and sprockets in good shape...you never know when you may have to 'lean' on them to get you home.
 

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I learned years ago to check your chain at times to test for stretch on the sprocket. Once the chain becomes stretched it rides toward the tops of the teeth and wears out the sprockets. Replace the chain before that happens and the sprockets last for several chains. I also lube my chains often with white lithium grease. Just a light spray on about 6" of chain every few times out and you have the necessary lube but it won't be flying everywhere.
I do the lube the short piece of chain visible on the rear sprocket method. Every time i get home with the chain warm. Moto cross chain grease which i assume would be very good to cope with the abuse they get
 

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Hi
Chain wear comparison is difficult between differing engine layouts.
The size of the power pulse through the chain, the frequency or the time between pulses all play a part.

A large power pulse on a heavy flywheeled low reving single cylinder 4 stroke engine will produce the most wear.
There is enough time between the pulses for the chain to unload and then the next power pulse will snatch the chain tight again. If the same engine was fitted with lower grearing and used at higher rpm chain wear would be less.

If you double the number of cylinders to 2, wear will be less. Halve the strength of power pulses but double the number. Wear will be less than the single
Triumph twins are in this category, however they are still relatively slow reving engine.
Triples are smooth enough to rev higher, Plus there is an extra pulse, shortening the time between power pulses.
Four Cylinder, these can rev higher, and have yet one more pulse to smooth out the delivery.
The effect is quite dramatic, this is why the same chain can be designated for a 200cc single and a 600cc four.

Wear on the chain and wear on the sprockets are two different things. The chain mostly wears internally, not on the contact points with the rollers.
The pins and plates wear inside when they are turned around the sprocket under load, a small amount of wear lots of times on every link soon adds up. The smaller the sprocket, the greater the angle each link has to turn, the greater the (angular) distance the pin turns against the chain plate, the greater the wear.
If you wish to have taller gearing (if possible) it is better to increase the number of teeth on the front sprocket, making the diameter bigger.
If you wish to lower the gearing (if possible) then it is better to increase the number of teeth on the rear sprocket.
Depending on the original ratio, a change of one tooth on the front is roughly equal to a change of two or three teeth on the back.

Wear on the sprocket is external due to the contact of the chain rollers on the sprocket teeth, the number of teeth in contact makes a difference, smaller = more wear.
The area of the contact patch affects wear, a bigger the contact patch lowers the pressure on each tooth reducing wear, wider sprockets wear less than narrow ones, this effectively means a 525 (5/16") chain wears the sprockets less than a 520 (1/4") chain on the same bike.
The material used to make the sprockets has a marked effect on wear, a harder the surface equals less wear.
You can have the Triumph front sprocket nitrided, but it is prohibitively expensive, but if you are having a crankshaft done anyway it is worth asking to have a couple of sprockets thrown in, the hard layer is thin but it takes a long time to get through it.

Chain strength does not automatically increase with width, 520, 525 and 530 chain designations are not indicators of the chain strength, but of sprocket load due to the contact patch area. The chain strength is dependent on construction (plate width, pin diameter, material used and design) it is marked separately on the box and varies a great deal.
My rule of thumb is if it is made in Japan by one of the major manufacturer, then it is likely to be good.

The great enemies for your chain:
1) Misalignment, this is the number one destroyer of chains and sprockets. An out of line chain will pull on one plate only, causing the pin to wear through it rapidly, the contact with the sprocket teeth on the chain roller will be a point contact causing high pressure and rapid wear, the side plates rub against the sprockets causing friction and adding metal to the debris on the chain.
The sprocket teeth clash with the chain rollers rather than sliding in.
Very easy to check, tell tale wear patterns show up. If you raise the rear wheel level and spin the wheel and look for the sprocket teeth engaging exactly in the centre of the roller, any (even if slight) deviation means misalignment, either from the position of the sprocket on the rear axle due to wrong spacing (rare) or the axle not adjusted square in the swing arm (common).

2) Lubrication, chains wear internally if you can keep the dirt out and the lubrication in the chain will last a long time, O ring and the better X ring chains do this automatically, and only need lube on the outside of the rollers.
Unfortunately Classic Triumphs cannot accommodate them (I believe there might be one O ring brand that now fits) so lubrication is very important, use special chain lube that is thin to go on and once the thinning agent has evaporated becomes thick and stick, hopefully the lubricant will penetrate inside the chain before it thickens, be generous and clean with the mess flung off later, hopefully it will fling off dirt with it. Do not use the waxes and surface lubricants designed for O and X ring chains, they will not penetrate into non-sealed chains.
3) Cleanliness, smart people clean their chains before lubricating their chains, most can’t be bothered (including me mos of the time), the paste made from dirt and lubricant can grind the chain and sprockets away.


Avoid any chain with split rollers, these are for low speed industrial use, look for solid rollers.

The Weakest Link.
This is the joining link, fit the best link you can, not the most convenient.
There are 3 common types, clip link, clip link with light interference fit of the plate on the pins, riveted link.

The Riveted link is almost a strong as the rest of the chain, If you have the chance always fit this type, however they require special tools to fit successfully, buy the tools as a lifetime investment. Learn to fit the chain link properly and you will not regret it.

Clip link with light interference fit on the plates, often used by racers for quick chain/sprocket changes to change gearing for different tracks. More secure than plain clips, not as good as riveted. Not recommend for road use.

Clip link, the least secure of the 3 main types, very convenient for removing/refitting the chain (never reuse the clip), If you have the chance upgrade to fully riveted. Most chain failures are due to lost clips.

I expect plenty of anecdotes of how you have ridden 80,000 miles a year for the past 1000 years, with a clip link chain, but you were lucky, there are just as many clip link failure stories. A broken chain can kill you, fit the strongest link possible-this means riveted.


Scottoilers,
This is one product that I have never seen a bad review of, everyone who fits one gives a glowing ‘best thing since sliced bread’ review. Double or treble chain life is often reported, the only complaint I have seen is the cost of the lubricant.
I suspect, without properly knowing, that the special lubricant used has a constant cleaning effect as well as constant lubrication.

regards
peg.
 

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Discussion Starter · #18 · (Edited)
I have a very small leak of gear oil at front sprocket. Just while riding. Works well. Never touch chain. Zero wear so far.
People silicone around the spindle to stop this leak ...

Another bike I'll soon have running doesn't leak here, unfortunately. 🤠

There's so many preferred methods. Was going to use gear oil (manually applied). I'll think about the Moto X grease.

I found this vid helpful

 

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Discussion Starter · #19 · (Edited)
A broken chain can kill you, fit the strongest link possible-this means riveted
I'm a bundle of nerves.

I reckon with no on-coming traffic or annoyingly placed street lamps, up to 40mph I'd survive oil starvation (conrod through crankcase), poor chain maintenance/quality/a clip link (whiplashed by chain), rapid inner tube deflation (head dive on tarmac).

Anyway, Peg, I'm working on reducing the odds. Is this a tool you was thinking of?
Auto part Font Metal Nozzle Cylinder


Costs less than £20, which isn't too bad.

Edit
Probably stupid question of the day. Can I rivet a clip-linked chain?

... I've seen this...
Automotive exterior Font Auto part Circle Automotive window part
 

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the key to reducing chain and sprocket wear is to buy another motorcycle, cutting the rate of wear by half on each one. better yet, own three motorcycles. your chain and sprocket life is tripled.
 
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