Hello again (the return of the bloke who can't write a short post)

So, I've been away from this site for a while.
I bought a Hyo GV250 cruiser (after writing off my zzr250) and had some minor problems but, after a while, it turned out that i was dreading riding it.
Since I'm a new rider anyway, I wondered if I just didn't like riding. So I sold the piglet and stopped riding.
Over the following weeks I got more and more itchy to be back on two wheels and my wife and my mates who ride all reminded me that I used to grin like a fool whenever I rode the zzr but stopped when I had the Hyosung.
After thinking about it for a while, I decided I'd look for a cheapy to give it another go. Among other things, I didn’t want to spend much in case I do decide against riding.
I had a look at a few things, mainly cruisers as I have stumpy little legs, but nothing really inspired me so I spent some time trawling through the web and considering options.
Finally, I set my sights on scoring an old VTR250.
Today I found a cheapy, visited the bloke and took his VTR for a quick ride. He explained that it had been sitting for a few years as it was his sons bike but he has been working in the Pilbara and Darwin and finally decided to let it go. When his dad first put it on Gumtree a few people turned up but he couldn’t get the bike to start. After a few attempts, he pulled it off Gumtree and spent some time with it. He drained the old fuel and flushed it with 98 before filling the tank, cleaned the plugs and replaced the battery with a new one. Once that was done it instantly fired up and he took it for a 100k run. Ever since then it’s been fine.
I took it for a short test ride and, apart for having trouble adjusting to the foot controls being right under me instead of miles in front of me, everything was fine.
Who am I kidding? It was awesome! Man, that was fun!
I came back and my wife said “Look at you, grinning like an idiot.” And 45 minutes later said “Are you still smiling from that one little ride?”
So, yeah, I’m going to take it. I’m collecting it next weekend and really can’t wait to be back on it.
Now, finally, to the point of this post...
The VTR has a Roo pipe fitted, which makes it sound pretty good, but I thought it smelled a bit rich. Idle was fine when it started but, once warmed up, it seemed to hunt a bit. After the ride both the smell and the idle seemed to have calmed down.
Now I am going to ride if for a bit before I do anything (though I might give in new plugs and and oil change) but I was wondering if the Roo pipe meant I should consider re-jetting the carby?
I’m guessing over the years a few of you would have had or worked on VTR’s so I’m chasing the voice of experience here.
Thanks

 

Thanks guys, all good tips, especially about 91; I'm in the habit of ignoring 91 at the servo and may never have considered it. Thanks for the photo @joker , even I can see the differences there
Frankly, I've spent all afternoon wondering how I can pick it up earlier ;-)

 

So, I pulled the plugs today and they look almost exactly like the 'Optimal' photo in the photo @joker shared. That was reassuring until I realised that the manual specifies NGK CR8EH and mine are CR9EH. That's not likely to make a big difference, is it?
And, when I went to collect it, I was told it had been topped up with 91. It was a bit of a dog right then, stalling if you turned the choke off, despite running for 10 minutes (on a warm Perth morning) but it improved once I'd gone a few k's. Idle settled down, choke was fully off and it was all pretty good. Except, even after 20 k's, it would hesitate on takeoff and then suddenly leap forward (honestly, officer, I really wasn't try to do a wheelie!) and, on the highway, it would do 95 but if I tried twisting for any more it would 'stagger' (the same sensation of building up tension prior to doing a big lurch) but if I backed off again it settled down fine.
Mind you, I still had a mighty big grin by the time I got home
I think I'll change the plugs anyway, and oil and filters, but does this sound like a problem any of you have experienced? Anything else I should be checking? I can't pin down why, but I seem to remember a similar problem with a car and I fixed it either by putting a kit through the carby, or replacing a leaking vacuum hose. ( I can't remember which and I may be wildly off base anyway!)