I don't remember if I had to remove the rear section of the exh. to service the air filter element, I don't think so. But I had the pipe off once anyhow, very easy. Just removed the two mounting bolts and it slid right off. I didn't even loosen the clamp.

Although the air box is very large for the engine displacement[a good thing], the filter element is rather small. So It's a good idea to check [clean]it often to maintain performance. A worth while mod. would be to fab. up a filter out of some dual stage foam[like the Uni Filter material. The original is just standard foam.
I looked the bike over last night and at 7500 Km, it's ready for a major service. I hate to admit it, but I skipped the first valve adjustment and now I can hear a slight tick. Also still runing the original Chinese plug and it's time to get a NGK in there.
The frt. spokes are loose again, the rears have been tightened three times[once a wheel true] and this will be the third time for the frt. It's normal for any new bike to need attention to the spokes, but this is a little excessive. I think the steel rims are a little soft and perhaps the spokes are somewhat big[in gauge] and don't flex much. Hence, the continual loosening. A pair of alum alloy rims[with the original spokes]would be a wise addition to this bike for anyone who off-roads or frenquents bad roads.
The first 3500 Km's, this bike saw a lot hard off road usage, but I got tired of being beat to death by the rear shock. It's fine in something like whoops or speed bumps, but hit a sharpe pot-hole and the rear suspension just locks up. Way too much compression damping. I'm 225 lb.s and I have the rear spring pre-load backed off almost all the way to try and soften it up. I have looked at modifying the linkage to increase the leverage, but the link is cast and impossible to mod. One thing a shorter rider could do, is to remove the shock and redrill the clevis end mounting holes closer to the shock body. This would reduce the seat height an inch or two. Plenty of room under the rear fender, probably 9 inchs or so and the wheel travel is only about 6 inches. For anyone off=roading this bike, I would sugest lookink fo a replacemnt shock.
The frt forks are passible. There is an audible clack on rebound[when they topout]that I have been told is common to this model. It sounds like the topping-out springs are missing, but frt forks haven't used topping-out springs for decades. It probably could use some fresh fork oil. I would recommend 15 wt.[mix 10wt. and 20wt.] and about 20cc's extra[measure what comes out to know how much]. Overall, they are stong forks that don't flex much, but they do creak in their clamps, but it doesn't seem to hurt anything.
Just to recap, I replaced the chain and rtear tire at 2K Km because I could see they weren't going to last very long. At the time, I replaced the 12 tooth counter-shaft sprocket with 13T. Perfect gearing for the road with a heavy rider like me. I think any higher gearing would result in excessive drive-line snatch[a shuddering in the transmission].
The bike is about 9 months old and has spent most of it's life out of doors and still looks new. Not a speck of rust and the plastic is as bright as ever. Very impressive!