Friday 7 January 2011

Honda NX650 Dominator


It was a bit dubious, buying a 32000 mile NX650. Only a year old, with just the one owner, there was a full service history and a guy who insisted he had never had a moment's trouble. The plastic still looked new, the red frame paint a bit faded and there was a lot of crud around the rear suspension but no unnecessary movement in the swinging arm. £1250 changed hands.

The NX has a 644cc OHC single cylinder engine that, new, develops 44hp at 6000rpm and 5.4kg-m at 5000rpm. With a dry weight of 400lbs, this added up, on my initial excursions, to not much grin inducing acceleration. It tottered along on tall, loose suspension. Below 2000rpm there was a lot of grating in the transmission, perhaps amplified by the engine balancer whirring away. Not that it exactly subsumed the vibes expected from such a large single.

If I ignored the transmission's protests then I found there was usable torque right down to 1000rpm even in top gear! Wrapping open the throttle as fast as my wrist could manage, made the engine gasp and stall if done from such perilously low revs. There was always a tendency for the engine to stall dead when rolling along at low revs or ticking over at junctions. Luckily, it took only a quick hit on the electric boot button to revive the motor. There wasn’t a kickstart fitted.

After a few days I'd become used to the way it would bounce around on its suspension. There was nine inches at the front and eight inches at the back, at least when new. With 32000 miles on the clock a good half of that was taken up as soon as I bounced on to the saddle. As the seat height was a leg stretching 34 inches, the worn suspension made waiting at junctions much more comfortable as I could get both feet firmly on the floor.

On the other hand, hitting the brakes with any kind of serious speed on the clock had the NX bouncing all over the place. Each end had a single disc, a strange set-up on a bike that was supposed to have some off-road ability. The rear groaned and creaked, always seemed on the verge of seizing up. It felt more like a drum brake with an oval casing than a state of the art disc brake. The front was more powerful, but when I got the Honda the pads were almost down to the metal, so they rattled around when the brake was not in use. In less than a month I deemed it necessary to strip them down, fit new seals and pads, give 'em a thorough clean-up.

They worked well after that, both powerful and sensitive, but they kept showing up the state of suspension. An R and R shock, slightly used from a breaker, was persuaded on to the back end, but only after I'd torn the Pro-link and swinging arm apart for a good greasing. I wasn't the first to have done that because there was still a trace of lubrication on the bushes, which were all in good shape. I'd got to them just in time.

The new shock had only four inches of travel, so I had to modify the forks to match, adding heavier springs. The gaiters had protected the legs, no pitting, and the seals were still intact. I was rather impressed with the chassis until I took a look at the sprockets. The teeth were so hooked that it was a wonder the chain hadn't flown off. New sprockets and a cheap chain (the OE was an O-ring job).

Back on the road, I was immediately impressed with the lower, tauter chassis. As it was a narrow single it was still impossible to scrape the engine in curves despite it being four inches nearer the tarmac. The bike had previously gone up to 85mph then felt like it was hitting a brick wall, whilst the whole beast wobbled laconically on its loose suspension. Now, 95mph was easily achieved and the chassis gave a wonderfully secure feel by way of contrast.

I quite enjoyed sticking the motor into fifth gear, using the throttle to determine my speed. This may have had something to do with the five speed gearbox which felt, to my liking, rather too much like an old Superdream's than a year old bike. Hard charging on the throttle would give a nice push come 5000rpm but more than 7500 revs had the engine falling apart in a frenzy of vibes.

Still, I was beginning to believe that the NX was a fun machine, especially in town where it could be flipped around cars and made enough noise to have cagers quaking in their seats. Even in the wet, the newish set of Avon Gripsters provided excellent grip and enough feedback to take outrageous risks. They were quite good on grass, too, something I found out when forced to go straight across a roundabout. The front didn't seem to wear at all, despite the fact that I only rarely wheelied the NX.

Top speed proved to be dead on the ton. Stability, once modified, was fine and the half fairing provided enough protection for 90mph cruising, although the screen was laughably low, an excess of water streaming into my lap in the wet. A few more inches all round would've transformed the protection. Even when riding like a lunatic, fuel turned out to be a tolerable 55mpg, as much as 65mpg possible under mild use.

At about 37000 miles, starting became difficult, fuel dropped to 50mpg and the Honda didn't want to do more than 85mph. I thought rebore or valve regrind time, but there wasn't any smoke out of the exhaust and no excessive rattles. Talking to another NX owner he reckoned a new air-filter might sort it. £15 poorer, I pulled the old one out after a minor hassle - sure enough, it was full of crud. Filter fitted, the engine was as good as new.

Feeling well pleased with myself until I realised that the chain had started flapping about. It should've had an easier time with the reduced suspension travel but in under 5000 miles it was in a terrible state. I tore it off before it broke and put on a high quality O-ring chain, something that the NX really needs with all those destructive thumper power pulses. As they last several times longer than plain chains in the long term it's money saved.

I hadn't done much to the engine, other than change the oil and filter every 1000 miles. This might be deemed excessive but on such a high mileage motor I thought it a good idea - the filters only cost £4 a throw. As a single with electronic ignition the only maintenance I had to do was check the valves, but they were always within tolerance.

It went through the 40,000 mile barrier in a blaze of sun in the South of France, where this type of bike is much more popular. Apart from touching up the frame every month, finish was still in line with its age, even the gold anodised wheel rims were like new - I'd given the bike a good clean every month. The only item to cause any concern was the upswept exhaust. It was loud when I bought the bike, by then was doing a passable imitation of a Sherman tank. Rust had blitzed the system, the baffle a long lost friend. The engine was so mildly tuned that, apart from a flat spot around 2500rpm, it still ran cleanly. When rozzers were around I pottered by at 1500rpm in top gear, the noise tolerable rather than raucous.

Coming back to the UK I was involved in a race with a Suzuki GSX550, which meant cruising at 95mph for about an hour along the motorway. I saw him off but coming home the engine was rattling and smoking. The clock read exactly 41,600 miles.
I had no time to check it over, a sudden dose of overtime had me working around the clock, just using the Honda for riding back and forth to work. I began to wonder, though, when the normally excellent light blew its bulb from the vibes and the front mudguard fell off. It was plastic, so self-destructed rather than making me fall off - it had never provided much protection in the rain, so I didn’t notice much difference riding around without it.

The end was nigh. For some stubborn reason I refused to take the bike off the road, rode it until just over 42000 miles the engine seized solid. The piston rings had broken up, ruining the bore in the process. What the hell, though, for £500 I bought a 3000 mile engine from the breaker, fitted it in over a weekend and was back in business.

The NX has crap suspension but an otherwise sturdy chassis that can take the occasional dance with the tarmac. Consumables, cheap chains apart, wear moderately and fuel consumption is good. The engine seems reliable to 40,000 miles, but could do with a bit more power and a better transmission (my low mileage engine is much better, to be fair). It needs hardly any maintenance and consumes sod all oil. Overall, I like the NX650, would recommend it to anyone not obsessed with outright speed. They are cheap secondhand, so bargains abound.

Phillip English

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The sheep were mad! Welsh maniacs that rushed under the front wheel as the Dominator and I thudded through the Brecon Beacons, cutting along a deserted track that was only marked on the most local of maps. The Dommie was loud thanks to a silencer degutted by nature (rusted out, to you) and some resonance of the exhaust sent the sheep into a frenzy even more intense than when they sighted a drunken Welsh farmer.

To keep some kind of order in the world I resorted to using top gear and low revs. An unholy alliance when thudding up the steeper hills that made the chain whip away on its sprockets. The whole bike seemed to vibrate with the intensity of the forces, my feet fast going dead. I felt lucky there were no bulls on the loose, the big red Honda a natural target for bovine anger. Cresting what seemed like the highest hill in the Beacons, the back end fell apart as if a sheep or two had been caught in the spokes.

I didn't really want to know how a previously pristine three year old NX survived a fall but can report than the indicators were wrecked. I hadn't killed a sheep or two, more's the pity, but the rear spokes had broken up, leaving an egg- shaped wheel. The bike could still be pushed but it had the same rolling resistance as a tank with flat tyres. Two hours later I came to a small town. At least the Welsh know how to drink and the pub was open all day long. I was quite happy when my mate turned up with a car and trailer four hours later for the exciting trek back to Bristol.

I had the choice of rebuilding the back wheel or buying a used one from the breakers. Because the rear disc brake was already seized into uselessness and the tyre was almost bald, a clean 17 incher with a drum brake was picked out of a pile of discarded wheels and bodged on without undue hammer work.

The tyre was a newish Avon AM which didn't match the front Gripster on a 21 inch loop. The NX felt like it wanted to go in two different directions at the same time. Any sensible person would've bought another rear tyre but I decided that a matching 17 inch front wheel was the answer. Back to the breakers but there was nothing with spokes but a nice used 17 inch Avon AM was found for a tenner. I had the front wheel rebuilt to suit the tyre. Just to complete the metamorphosis a shorter rear shock was added, the OE one already turning to mush after 14000 miles of abuse. The damping couldn't control the machinations of the back wheel after it attacked a pot-hole.

I was petty pleased with myself as the standard seat height was around 35 inches, which left me tottering on tip-toes when waiting at junctions. Yes, people laughed at me and I fell over a couple of times when the camber of the road surface was extreme, but protected the bike from damage with my fallen body. Taking two inches out of the ride height did wonders for my confidence and enhanced the security of the handling. All this because of those mad Welsh sheep!

The Dommie has a big thumper motor that has more than a passing resemblance to the old XBR unit (strange that you don't see many on the road, these days). The NX has less power than the XBR, only 40 horses at 6500 revs and torque peaks out some 2000 revs lower. This means it'll run along quite nicely in top gear for most of the time, although those of a sensitive nature might be better off using the gearbox to avoid 2500 to 3500 revs, as the intricacies of balancing a big thumper break down within those revs. Even then it's annoying rather than especially bad - if you come across an example that thrums the tank noticeably don't buy it as the mill's probably on the way out. A naff engine ain't a disaster as they are simple to work on and there are quite a few bikes in breakers (usually with bent front ends).

I don't find the vibes really annoying, although they are heavier than a straight four they are not so intrusive - you have to try one to understand what I'm getting at. The NX runs on torque rather than power, probably ideal for Harley owners who want something to ride in the winter or go shopping on. This thumping torque has all the more effect because the Dommie weighs under 350lbs and the fairing has a passing stab at aerodynamic efficiency. Putting 115mph on the clock ain't impossible, although above the ton it's hard work. 90mph cruising, especially with the lowered suspension, was pretty easy going. The fairing actually whipped a lot of the wind around me at that speed.

The only complication was the 100 mile range, a combination of three gallon tank and 35 to 40mpg. For sure, 45 or even 50mpg was possible but that needed softly, softly riding (ie no wheelies) which turned me crazy with the outrageous boredom of it all. The poor economy was probably down to an engine design that has its origins in the 250cc model (which is quite economical) and the effort needed to balance a four inch slug of a piston even when moving through a relatively short stroke.

A stock bike's handling is generally good. Better in town, where it deals well with pot-holes, than on the open road, where bumpy bends will set up a bit of wallowing, especially after the suspension has worn out a bit. With the shorter, tauter shock and smaller front wheel most of the wallowing went away. The only hassle was that on slow speed, sharp corners the front wheel would try to tuck in if the single disc was applied even gently. I didn't notice any lack of leverage due to the smaller front wheel size, doubtless a result of the change in tyres.

Tyre and brake pad life was quite reasonable, expect over 10,000 miles from Avons and EBC's. The chain and sprockets suffered both from the thumper power strokes and my daily wheelie, less than 5000 miles a set. I keep thinking about robbing a big Harley of its belt drive.

The horrible plastic around the forks and disc was easily removed although the very sensible fork gaiters were retained. The hand-guards come out in the winter but their lack of aesthetics don't make it in the summer. To my eyes the tank and fairing look horrible but there's no cheap way of replacing them - oh, for an old Triumph tank. The seat, with 30 thou on the clock, had gone hard enough to cause piles after 50 miles, although it'd never been good for much more than 200 miles in a day even when it was in reasonable shape. The front light was excellent and I couldn't really fault any of the controls.

The NX, being air-cooled, is a relatively simple device that would surely benefit from a more conventional seat and tank - judging from the XBR's sales, perhaps not. As a ritzy road bike with a large element of practicality the Dommie comes across as a winner and better than most dual purpose tools. New examples obviously lose out to the BMW F650 but used ones are available for as little as a grand for an early model, although twice that's needed for a really nice one. There are lots of clean examples on offer in the private market.

My bike now has 49000 miles on the clock and a new exhaust system. The finish is still excellent despite constant winter use but not despatching - I know one guy who completely ruined an NX in ten months and 50,000 miles of despatching, both chassis and engine completely knackered. That reminds me, I had to take the Pro-Link down twice a year to keep the whole mess from seizing up (I don't know what's wrong with twin shocks) and I've had to put in one set of bushes (at 28 thou).

The engine's a good old slogger as long as you keep away from the red line. Valves can be left for 5000 miles and there's sod all else to piss around with, save for 2500 mile oil/filter changes. There's a slight bit of oil weeping from the cylinder head gasket and some more coming out of one of the gearbox seals. The bike will still knock its way through the ton but I haven't seen 115mph for about 20,000 miles.

Harry West