[h=2]Chains 101 Maintenance and Wear[/h] Disclaimer. This information is from various sources on the internet. It has not been verified. I am not an engineer or mechanic or have any other specialised knowledge of this topic. This information and any conclusions I make could be incorrect. Do your own validation of this information before you use it. In all cases follow your manufacturer’s recommendations. Chains, Belts or Shaft? Chain drives use sprockets and a roller chain, which requires both lubrication and adjustment for stretch that occurs through wear. They transmit power very efficiently. Motorcycles are one of the most demanding applications for a metal chain as they often handle high power and speed and are exposed to a large volume of contaminants and extreme environmental conditions. Though Hans Renold is credited with inventing roller chain in 1880, sketches by Leonardo da Vinci in the 16th century show a chain with a roller bearing. A belt drive is still subject to stretch but operates very quietly, cleanly and efficiently. They do not require lubrication. Belt drives are limited in the amount of power they can transmit. A toothed belt is frequently used. They usually last longer than chains but are more expensive to replace. A shaft final drive is housed within a rear swingarm. This arrangement is superior in terms of noise and cleanliness and is virtually maintenance free, with the exception of occasional fluid changes. However, the additional gears required are a source of power loss and added weight. Pitch and O / X Rings Chains are precisely made devices. The distance between the links is the pitch. 520, 525 and 530 chains have the same pitch. The O or X rings were a major advance in chain design reducing the frequency of lubrication and reducing wear by keeping the lube on the chain pins for longer and keeping debris away from the moving parts. These soft rubber rings are easily damaged so care is needed when maintaining the chain. Lubrication All chains, even O and X ring chains, need lubrication and occasional cleaning. This has the greatest influence on chain wear and therefore serviceable life. The outside and the inner surfaces between the pins and bushings and the bushings and rollers require lubrication. Ensure you use lubricant that is suitable for O ring chains. Solvents (including WD40) may dry out the O rings and increase chain wear. High pressure hoses can force the lube out of the pins. Wax type lubes have minimal fling-off but tend to collect dirt and are best applied on a warm chain. Oil type chains tend to fling onto the wheel rim but do not collect as much dirt as the wax types, application onto a warm chain is preferred. How long Do Chains Last? That depends. If you regularly maintain and inspect your chain they can last safely for many thousands of miles past the often quoted life. If you don’t inspect our chain then its easiest and safest to replace it regularly. The service life also depends on the chain being kept aligned and at the correct tension. Worn Chains A worn chain, apart from the risk of breaking or skipping off the drive sprocket, leads to an increase in the rate of wear of the sprockets with which it mates. The sprockets cannot change the spacing of their teeth to match the increasing spacing of the links or "pitch". Worn chains grind a characteristic hooked shape into the rearward face of the sprocket teeth. Chain wear is rapid early in the chains life (20 hrs); it then wears slowly until near the end of its life when the wear rapidly accelerates again. If you remove all the lubricants with solvents, the wear progresses along a nearly straight line and the life of the chain is shortened Chains Wear, Not Stretch Chains do not stretch. The “stretch” is due to wear between the pins and bushes. This increases the spacing of the pins (changed pitch) causing the chain to grow longer. (There is some argument that they stretch in the first few hundred ks with at least one manufacturer selling pre-stretched chain though this may be the rapid early wear described above) Parts of the chain can wear at different rates giving the appearance of a loose / tight spot when the wheel is rotated. The area of greatest wear is where the chain is the loosest and this is where the maximum stretch should be measured. A new chain will not have play along its length whereas a worn chain will. Wear Limits - 1.5% Chain wear should be measured at the loosest part of the chain as this is the area with the greatest wear. The commonly accepted maximum stretch for chains seems to be 1.5% but commentary varies this from 1% to 3%. Testing shows that when wear elongation is less than or equal to 1.5 percent for a transmission chain there is almost no risk of fatigue failure. A simple and effective method of checking for chain wear is to pull the rearmost link on the back sprocket away from the sprocket. A worn chain will lift a little off the sprocket. If the gap between the sprocket and the roller is greater than 1.5mm (some say .75mm) the chain should be replaced. As with all wear measurements make sure the loosest part of the chain is on the rear sprocket when you test it. Other things to look for: Stiff or stuck links - indicates the internal lube has gone and therefore a high wear area , especially with reddish rust spots or powder. Cracked side plates / elongaged pin holes indicates the chain damages and needs replacement. Rotated Pins Wear on one side of the chain indicates the chain (back wheel) is not aligned properly. Damaged X/O rings wont retain the lub in the pins and will let in dust etc. The master link is secure and not damaged. Sprocket teeth are worn. Sprocket Wear It is often not necessary to replace the front and rear sprockets when the chain is replaced despite what your mechanic says. Commentary suggest that sprockets can be replaced every second chain. Of course this depends on the wear in the sprockets (determined by how long a worn chain has been used). Inspect the sprocket before deciding if they need to be replaced. If they are not worn this should have a minimal impact on the life of the chain. The replacement of the sprockets is a sensible “no regrets” decision by the mechanic. If they are replaced, he gets extra fees and if anything goes wrong it is due to manufacturing fault. If he doesn’t change it, he misses out on extra revenue and if something does go wrong it is because he did not service your bike properly. Safest and best decision for him is full replacement. To give some indication of how much this can cost. If I went with the mechanic / bike shops recommendation I would have bought the "best" chain (apparently Ducati's need the best) which was an X ring for about $360 plus front and back sprockets (say) $200 = $560. Instead i purchased an O ring chain from th same manufacturer (x rings are supposed to be better but I lube my chain regularly anyway) for $100 and as my sprockets were not worn I kept them = saving $460 or a set of tyres. However, this is my choice and I am not recommending it is correct for you. Method - Chain Cleaning (every 1000km though you may choose to do this every second lubing) This can be easily done with the chain on the bike. Never go near your chain while the engine is running (even if out of gear). Look on U-tube if you want to see amputations caused by fingers getting caught in rotating chains. 1. Secure your bike with the back wheel a clear of the ground. 2. Put your bike in Neutral so you can turn the back wheel by hand. 3. Measure the chain for wear and inspect (rust spots, cracked plates, loose or rotated pins, binding links). Ensure the master link is in good order. Replace chain if required. 4. Spray or paint (with a soft brush) on to the chain appropriate cleaning fluid suitable for O (x) ring chains while you rotate the back wheel. Kerosene (Paraffin oil) is excellent. Do not use highly solvent fluids such as WD40 or high pressure water that can force the existing lube out of the links. 5. If the chain is very dirty clean with a soft brush so that the o/x rings are not damaged. 6. Wipe the chain with a cloth to remove all cleaning solution and dirt prior to lubing. 7. Check the chain alignment and free play according to your owner manual. Method - Chain Lubing (at least every 1000km, more in wet weather or hard conditions / service) This can be easily done with the chain on the bike. Never go near your chain while the engine is running (even if out of gear). Look on U-tube if you want to see amputations caused by fingers getting caught in rotating chains. 1. Take the bike for a short ride to warm the chain 2. Secure your bike with the back wheel clear of the ground. 3. Put your bike in Neutral so you can turn the back wheel by hand. 4. Measure the chain for wear and inspect (rust spots, cracked plates, loose or rotated pins, binding links). Ensure the master link is in good order. Replace chain if required. 5. Ensure the chain is relatively clean (it does not need to be cleaned every time it is lubed) 6. Spray the lube on the inside of the chain plates on each side of the chain as you rotate the back wheel. Apply a liberal coating but do not overspray as it will just be flung off. 7. Ensure the O/x rings, and rollers are lubricated. 8. Do not use the bike for 10-15 minutes to allow the lube to “set”’.
