I have a CDU 250; great bike, good two up on county lanes. Does leak petrol if the tank is full from around the fuel cap. Cruises 70-80 top. Good solid traditional bike.
Finest commuter machine I have had. Now at 40,000 miles, upped the gearing to 29 tooth rear, better than one less tooth up front. With respect to age, not over 60mph, have my doubts on speeds specified on original low gearing. Change the oil every two months, with a small sump, a good thing for Japanese bikes.
The CB Two-fifty which followed the CD250U reverted to single carb & had a rubbish performance without better MPG. The only prob with the CD was it was physically too small for most people.
I have owned and ridden two CD250U motorcycles, and both have been brilliant. They can easily travel at 100km per hour freeway speed, except up hills into a head wind, when 85-90 km/h is more realistic. They can beat virtually any car at the lights. I use 4 litres fuel per 100km around town.
Front disc brake is excellent, rear drum is OK. Any more stopping power on the back and the rear tyre would skid. The seating is very comfortable for long trips.
Rear sprocket links to rear wheel with 4 pegs mounted in rubber bushes. If the bushes fail (as they will) the sprocket will wobble and break the flange on the wheel hub holding the retaining circlip. The rear sprocket will then free-wheel and drive is lost. It's a design fault, but just needs an eye kept on the bushes with scheduled servicing.
I recently purchased an 1989 CD. Since owning it I have put on a front sprocket with 1 extra tooth. Wow, what a difference it made to the ride. Now rides at 100kph relatively easy, except as mentioned up large hills. It has 11500 km on the clock.
I increased the headlight from a 0/45 watt to a halogen 55/60 watt. In order to avoid wiring melting problems, I had it wired direct from the battery with a relay inside the headlight, still using the original hi/low switch wiring.
All in all I love this bike. I have owned many motorcycles over the years of all sizes. I have spent a bit of money on the bike e.g. had the centrifugal type oil filter inside the clutch cover cleaned, as there is no other oil filter, and over time they can pick up a few bits and pieces.
From a full tank of fuel I run it on premium unleaded, and by the time I need to turn on the reserve tank, I have traveled 250 km around town.
Purrs like a kitten; great motorcycle, Have done long trips no problem, and now that it has just turned 25 years old, it still turns the odd head and gets nods of appreciation.
I just stumbled across your valuable posts in regards to the CD250U. Yes the above review is completely useless; the CD250U I have has twin carburetors and it's a pretty good machine.
The reason why I am posting this comment is, I would like to know what is the average MPG (UK or US, please mention when you state it)? I managed to tune up my carbs and spark plugs; looks pretty clean, and the bike runs great, but it does only around 22 KM per liter, which is around 62 MPG (imperial).