A few comments to compliment what's been mentioned above; China had a great network of prepped mechanics so if you speak Chinese you can get in with the club and those guys stick proper parts. Don't touch oil unless you know the brand, 40rmb Castrol seems like a good deal until it's completely burnt out 500km down the road. A heavy weight 20-w40 Motal or Repsol (~140rmb) will give you a good 3k without issue. The problem is that it's only found in 'real' garages' which are hard to find without proper knowledge.

Every time you change your oil make sure to grease the chain and check your tyre pressures. There's no need for fancy chain lube, you can just slap a load of engine oil on the chain for good measure.

High altitude plugs are a lie, it's the carb needle that upgrading at altitude. I've bought into triple header spark plugs before and they really don't make too much difference at all; we're talking thousands of km of latitude and standard plugs run fine. It's the carb that you should attend to.

If you have any serous issues feel free to email me@ sjskerr@gmail.com for in particulars.

I do apologise if my English is poor or I've missed something because I'm on a very slow phone and I'm slightly drunk due to Bowies death.