Hi,
I have a GB350S and I have put 1600 miles on it so far. The engine loosened up after about 800 miles. So if your test ride is on a lower mileage bike - expect it to get better after 800 miles. 21 horse power doesn't sound like much, but it comes at 5500rpm. I fitted a tacho, and so far I haven't exceeded 4000rpm by much. So I haven't ever used all 21 horses. 3000rpm in 5th is about 50mph. 4100rpm in 5th is 70mph.
On the dual carriageway I can cruise comfortably between 65 and 70 mph. 70mph is available on the flat without going to full throttle. I have never been to full throttle on my GB350S. The bike tells me I am doing 100mpg. That combined with the 15 litre tank, means refills are about 300 miles apart - all bikes should be like that. Once the fuel gauge starts flashing, I get about 13 litres in.
I did the 600 mile service myself, 2 litres of standard Honda 10w30 JASO MA oil, and an oil filter for a CB125. It was easy. Don't forget the O-ring or sump crush washer.
The bike is lovely to ride, but you ride in the traffic not over it. Filtering is clearly easy on such a small, light bike. Handling is good. I love it.
