Join Date: Dec 2013
Location: Mexico City
Motorcycle: GSX-R 750, Versys 650
What actually causes stiff links in chains?
I know, the pins rust and the link seizes, easy... But why? How does water get in there and displace the factory lube?
My Versys eats chains, never got one to last more than 125000 miles and that chain actually scratched the engine case (not the case, but the neutral switch cover). Usually I only get 10,000 miles out of them...
Except for the current Bike Master chain, 6250 miles and has no less than 10 stiff links...
I'm not anal about chain maintenance, but 6250 miles is ridiculous. To add insult to the injury I was very carefull with this chain as I installed it last September, so it didn't even get a lot of rain! The little rain it got I made sure it was dry and that there was still lube on the chain when the bike was parked. I'm thinking there is more to it than just chain lube.
Thinking back, I've only had two other bikes that ate chains like that, Yamaha XT660s (XT660R and XT660X). Back then I thought it was because they were thumpers, but the Versys is a twin... Then I caught something, all three bikes come with 520 chains, every other bike I've had used a 525 or a 530. I've done lots of miles on these 520 chained bikes as they have been used for commuting and touring. Regardless of how consistent I was with chain maintenance, what kind of lube was used, sprockets replaced or not along with the chain, they were all toast by the 10,000 mile mark.
My previous theory, that I now believe to be completely false, was that if a chain was not dried/lubed and the bike parked with a wet chain it would corrode. This corrosion would then cause the o-rings to fail, lube to escape and allow water ingress.
Another theory is that when ridden in the rain, specially when going through puddles or standing water at speed, the spĺash of water might be strong enough to seep past the o-rings; similar to what happens if you direct the pressure washer to the chain or a seal.
New theory, based on my experience of low 520 chain life vs. 525 long life, is flex. As you accelerate / deaccelerate the side of the chain that is not under tension flexes as the links are pushed by the driving sprocket at higher speed than the speed of the links not under tension, moreso as the pins wear and there is more play. Flex will cause the o-rings to have less pressure on the side plates allowing lube to escape, maybe some water ingress to... But an air void left by the lost lubricant will be filled by air that will expand and contract, drawing ambient moisture into the chain. Pins on a 525 chain have more surface and wear at a slower rate, also being longer means they will allow for less play keeping good pressure on the o-rings.