| It's a common problem. The preload adjuster should be at the same angle as the compression adjuster. As Felix says, you need to compress the spring to access the second lock ring, not DIY unless you have a proper spring compressor!!!
If you've only got about 4mm clearance with the bike just sitting there then you'll probably have a clearance problem - the adjuster swings in closer towards the pipes with suspension travel. Easiest way to sort out is to loosen all the exhaust mounting bolts off (especially the ones that hold the balance pipes to the frame) and pull the whole exhaust as far backwards as you can then tighten up again. Should give you ample clearance. | 
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