Big day in the workshop.
I had recently completed a five day, 1,600km (~1,000mile) ride. On the last day and a half I noticed the bike behaving differently, with the bike "surging" at times, most felt when climbing big hills.
Back home I ran a couple of compression tests; both showed 165psi on WOT which was higher than expected; possibly a decoke is required?
The spark plugs were changed (the UCE350 runs a twin plug head with two coils) and I tested the leads (both OK) yet the problem persisted.
Next suspect was the chain and / or sprockets. I had ordered a new front & rear sprocket from India with FedEx airmail, and picked up a new chain locally. Incidentally the sprockets travelled India - China - Japan - Singapore - Australia - New Zealand in under two weeks!
On strip down the front sprocket was very worn with sharp edges, the back not so bad. I hadn't touched either when replacing the OEM chain at about 10,000km's, and I'd travelled another 21,00kms on the second, Regina branded, chain.
The side cover was sealed back up and, while running the engine up and then waiting to check for leaks, I used the time to replace the front brake pads and pump fresh fluid through the master cylinder and calliper.
The test ride late this afternoon showed the bike back to its normal, much smoother, self.
The trusty 350 is now ready for it's next big adventure