I had a Cougar until it got written off, but that was one thing I noticed - how much the rear wheel loved spinning up on even the slightest damp patch, not to mention going over a grid in the wet round a corner! I think it was mainly due to the weight the back end had especially with me on it. But that was a really fun part to the bike, the weight and width of the machine felt like you were riding a much bigger bike than a 125.
One thing I made sure to do when I first got it home though was changine all the perishables: Engine oil, Brake fluid, Brake pads/shoes, Spark plugs and Fork seals, Oil filter, fuel filter and Air filter. The difference in the ride quality after was second to none. Slowly but surely buying more specialised parts to improve the quality of the bike. The first port of call was a new chain because my god it didn't half stretch. Moved up to Hagon twin shocks with adjustable pre-load - felt like I was on a memory foam sofa with them on. Swapped out the fork springs for softer springs to ease the front end better over bumps in the road. With a nice set of part-worn Bridgestone tyres the bike started to feel like it should of done from the start. I think everything I bought for the bike totaled up to about £600's worth of kit, but didn't half improve the bike! by far the best 125 I've ever ridden (Even if I do say so myself).
The only thing that let me down big style and it has been mentioned is the electrics. Italian electrics just don't seem to like British weather. Forever cleaning contacts, replacing fuses and bulbs. A problem they really should of sorted out before production.
Like Tattoo John's response to benjiii, I would expect the wrong throttle cable has been bought, which generally seems odd because they aren't exactly dear...
midlandsdoc I had the same problem, until I could find a piece of rubber with the quality for a bush I actually removed the old nackered bush and swapped it out for two metal washers. Not exactly the perfect replacement but it worked, no free play from the risers so in turn the steering was more responsive.
bikeboy85 I'm confused, does it not have an ignition barrel/switch? Like tappy said it raises suspicion as to wether the bike has been stolen..