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Honda NX 650 Dominator

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Make Model

Honda NX 650 Dominator

Year

1991

Engine

Four-stroke, single cylinder, SOHC, 4 valve per cylinder

Capacity

644 cc / 39.2 cu-in
Bore x Stroke 100 x 82 mm
Cooling System Air cooled
Compression Ratio 8.3:1

Induction

Single 40mm Keihin  VE-type carb

Ignition 

Digital CDI
Starting Electric
Spark Plug NGK, DPR 8EA-9
Engine Oil Semi-Synthetic, 10W/40

Max Power

45 hp / 33.5 kW @ 6000 rpm

Max Torque

53 Nm / 5.7 kgf-m @ 5000 rpm

Clutch Wet, multiple discs, cable operated

Transmission

5 Speed 
Final Drive Chain
Frame Steel, Single cradle frame

Front Suspension

41mm leading-axle fork
Front Wheel Travel 220 mm / 8.6 in

Rear Suspension

Pro-Link,
Rear Wheel Travel 195 mm / 7.6 in

Front Brakes

Single 256mm disc 2 piston caliper

Rear Brakes

Single 220mm disc 1 piston caliper

Front Tyre

90/90–21

Rear Tyre

120/90–17
Fork Angle 62°
Trail 115 mm / 4.5 in
Wheelbase 1435 mm / 56.4 in
Seat Height 870 mm / 24.2 in
Ground Clearance  250 mm / 9.8 in
Dry Weight 163 kg / 359.3 lbs

Wet Weight

178 kg / 392.4 lbs

Fuel Capacity

16 Litres / 4.2 US gal

Consumption Average

17.8 km/lit

Braking 60 - 0 / 100 - 0

13.8 m / 40.4 m

Standing ¼ Mile  

13.9 sec / 147.8 km/h

Top Speed

160.8 km/h / 100 mph

Road Test

Motosprint Group Test 1990

Tarn not a lover of big singles, I apart from their ability to X make nice noises and, in the case of big trail bikes, their immense comfort and practicality for local journeys.

Attempt long journeys and the limitations of the engine soon become apparent. All the world and his wife go thundering past, closely followed by their entire estate packed into a removal truck. You open the throttle at 80mph to find that it is already open.

Attempt a muddy trail and the limitations of the chassis make themselves very clear. Big trail bikes are easy to ride into deep ruts but they are less than easy to ride out again.

Honda's NX650 Dominator goes quite a long way to change all that. I regard it as an honorary twin, although maybe that has got more to do with its name and the fact that Honda have put two large exhaust cans under its tail. Or maybe it's psychological, in the same way that I remain firmly convinced that the Transalp has a shaft drive.

The best thing about the Dominator is that, compared to other big trail bikes, it feels no more cumbersome than a 250, while keeping the grand luxury of a forty inch seat height and several metres of suspension travel. On this machine you could contemplate serious trail riding.

And it makes nice noises, two at a time from the unequal-length, twin stainless system. It is perfect for riding to work, zipping into town, strapping shopping to the back rack, which sits flush with the seat and so can handle quite bulky items.

Its performance is on a par with other big trailers — 90-odd sitting up, and 80-odd is often a struggle when the elements and bulky oversuits combine against the 37 horsepower bike plus the aerodynamics of a brick with large air scoops all over it. It hit 105.5mph during our top speed runs, but it was so deep into the red that it wouldn't do the engine much good to ride like that for very long. Perhaps we should try raising the gearing by a tooth or two — it is certainly flexible enough to pull it. One of the nicest features is the thump which comes in at 4500 — although the rider feels it best when he opens the throttle just above 3000 and the motor cracks on to the increasing part of the torque curve where wheelies start to get a bit exponential.

Below this speed, around 2000 to 3000rpm, it goes through a really chunky vibration period which shakes the bodywork from side to side like a terrier grappling with the first  rat of the day. Honda have prepared themselves for this and have mounted the plastic on things that look like flexible rubber rawlplugs. So it all flaps about without doing itself any mischief. If rats had been developed by the Japanese, terriers would be out of business by now.

Actually it wasn't completely devoid of vibratory problems. Within a couple of weeks, both rear indicator mounts had broken. The indicator stalks are mounted on a central screw, with a little peg which presumably stops the indicator from twisting. The pegs disappeared, which may have been caused by vibration because the nuts loosened off as well, or it may have been caused by people putting bungees around the indicator stalks because the holes in the rear carrier are the wrong shape.

The only other damage it suffered was some broken rear plastic when Sarah got a bit over-enthusiastic and rear-ended Fiona. Or it could have been the other way round (that's enough of that, Editor). Otherwise the old Norton has proven itself to be eminently crashproof. Or rather, Mark proved it at Three Sisters when he turned a half-Freddie into a full Sarron on the way out of turn ten. And not a mark on it, ho ho. In its 10,000 mile career, the Dominator has probably done more miles on race tracks than it has on trails. It crossed the Pennines on a largely off-road route, and it spent a practice day at Mallory, where it wasn't the slowest machine on the track and where Mark managed to scrape the paint off the footrest hangers. ("If you can ground a big trail bike then you are either fat or clever", P. Comely, 1989, expert on big trail bikes and owner of several refrigerators).

We picked the bike up with 8,000-odd miles on the clock this year, but a close look at the sump plug revealed it to be the very same machine that we tested last year. The mechanic who serviced it must have wondered why a trail bike would come back with its sump plug lock-wired. The answer is that it had just come fourth in a hill climb immediately after two days of getting up to its waist in Yorkshire mud, racing a Trans-alp across the Cat and Fiddle and doing half a dozen laps of Oliver's Mount. All on the same tyres.

The OE Dunlops actually work very well and their wet grip is good, too. The only problem was that they showed a tendency to slide very suddenly when the bike was well banked over. I suppose that it was predictable in the sense that it was inevitable; but it was unpredictable in the sense that you never knew when.

The first test (Oct 88) proved that it was the most versatile of the big trailers, even if it was slower than the Transalp. The second test is demonstrating its versatility over a long term. It has now put 2000 more miles on to its very varied total; more race tracks, more motorways but mostly general commuting — all without incident, apart from the morning when the Honda wouldn't start. We tried all the usual things — pretending to ignore it, creeping up on it suddenly, pushing it up and down the road and then we found the cure. This involved fetching a CBR and using it to tow the Dominator to the nearest dealer. The dealer put the spark plug lead back on and all was well.

(Editor's note: quite why the Technical Editor of the most revered magazine in the UK should be unable to locate a loose HT lead is something which provided much entertainment for the rest of the week).

(Technical Editor's note: the reason is simple. Being towed down a bumpy road behind a CBR looked like being more fun than getting at the spark plug buried somewhere deep inside the Dominator. You'd need to be a gynaecologist to even contemplate changing it).

Ride comfort, handling, braking, midrange grunt are all pretty good. Pillioning isn't too bad but the extra suspension travel does some weird things to the steering. It feels nice to sit on, there are a few quality touches and, after 10,000 miles the whole thing feels free and loose. The only regular complaint is that the main tank runs out at about 95 miles.

Perhaps the best thing about it is the light, positive handling which is perfect for back roads and for heavy traffic. It has revised my opinion of big singles, but I'm not fully convinced that 37 horsepower is enough...