Std exhaust silencer weight

[His Dudeness]

[quote author=His Dudeness link=topic=24637.msg285708#msg285708 date=1540022220]
Think about it why does the chain need slack in the first place? It’s because you have to allow for changes in chain tension due to the up and down movement of the swing arm due to the suspension compressing and extending. The position of the front sprocket is fixed rigid to the engine and the engine is bolted into the frame so the position of the front sprocket can’t move up or down but the rear sprocket is part of the swing arm assembly so the position of the rear sprocket changes, it has to move up and down relative to the front sprocket when the swing arm moves up and down. If you look at picture 1


Imagine that picture 1 is when both wheels are on the ground the distance on side A is equal to the distance on B. In picture 2 say you hit a bump as you're riding and the suspension compresses and the swing arm pivots up around it’s pivot point so the rear sprocket pivots up relative to the front sprocket. This means the distance on side A will get shorter and side B will get longer so the tension on side A will be less and the tension on side B will be greater. That's why you need slack in the chain.

In picture 3 when you put the bike on the centre stand you’re doing the opposite, you’re taking the weight off the rear suspension so the suspension extends and the swing arm pivots down so side A would get longer and side B would get shorter creating more tension on side A and more slack on side B. That means if you adjust the chain to have 30mm slack on side B when the bike is on the centre stand, when you put it back down onto it’s wheels and the suspension compresses and the swing arm pivots up side B will tighten up and you’ll have less than 30mm slack. YamFazFan proved that’s what happens with his measurements. On the centre stand he measured 30mm slack. When he put the bike on both wheels he measured 26mm because the weight of the bike caused the suspension to compress and the swing arm to pivot up slightly. The slack side will tighten even more when you sit on the bike because you’re compressing the suspension more and that’s causing the swing arm to pivot up more. It'll tighten more if you have a pillion. And it'll tighten more when you hit a bump in the road.

Pictures 2 & 3 are the same, just the reverse of each other.
I think irrespective of how you check your chain slack, whether on centre or side stand, once you know what feels right you'll know what to do next time anyway.
I don't even measure any more, i started using the "Unfazed" way by pushing the chain up until it just hits the chain slide. It seems to be adequate enough.
And don't forget the manual suggests 30-45mm play on my bike so it's not that critical. It's the sound effects that play more an important role for me.
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Of course it's a mirror image because the swing arm pivots around the same point whether it's pivoting up or down so the effect is the same just on opposite sides of the chain.

Say YamFazman found that it's a 5mm difference just from the weight of the bike. 5mm difference when the spec is 30mm-45mm that's 11% to 17% difference just from the weight of the bike. Sit a 100kg rider on the bike and the slack side will tighten more probably another few mm. Sit a 60kg pillion on and it'll tighten more, then add in hitting bumps and it tightens more. It would be made even worse if your chain was a bit old and had a tight spot in it. Does adjusting it on the centre stand make such a huge difference that it causes major problems? It seems not based on the fact that some people adjust it on the centre stand and get away with it but the point that I'm try to explain is that is it does make a difference. They give you the 30mm-45mm spec for when both wheels are on the ground so if you're using the 30mm-45mm as your guide you have to have both wheels on the ground to get the right amount of slack. Saying that adjusting it on the centre stand makes no difference isn't correct