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View Full Version : Honda GB400TT review



OddDuck
19th May 2015, 13:25
These still fetch interest today as collectible / cult / learner bikes. I bought mine as my third bike and ran it for over ten years, over much of that time as my primary and only transport. I'd tried the GB500 and decided that the 400 was much smoother, at the cost of some power.

People like them. The style is popular and they’re quite affordable.

It’s a dirt bike motor in a commuter frame, dressed up to look like a Japanese take on a ‘60’s Brit single. Physically, by the standards of modern bikes, it’s quite small. The seat height is low enough that shorter riders are comfortable and it’s probably best matched to someone between 5”6’ and 5”10’ tall.

It’s light. The whole thing weighs in at 165kg dry and is a doddle to maneuver by hand in driveways, parking lots etc, in sharp contrast to the usual 200 kg+ modern beast. It’s also astonishingly cheap to run. It isn’t thirsty on gas and tyres are cheap, owing to the minimal section. It has the usual Honda reliability and easy starting. The stock muffler is very quiet and you won’t need your earplugs when riding below highway speeds. Engine vibrations are minimal and it’s quite easy to tour all day long, owing to the fairly relaxed riding position. Maintenance is helped greatly by it having a centerstand. The engine features electric and kick start, which can be very useful if your battery is getting a bit dodgy. It’s also very easy and very forgiving to ride, provided that you aren’t trying to race. Range per tank is excellent, but highly dependent on windage / rider weight / riding style, so I won’t quote figures.

Unfortunately it’s a bit gutless. Stock power is rated at just 29 HP peak, and this will go down badly if it’s got worn rings / fouled valves / over-rich carburetion etc.

The suspension is cheap, too. Neither front nor rear features much in the way of adjustment. You can change the damping oil in the front, you can set the preload in the rear. That’s about it. The stock shocks and springs are definitely on the light side for the average Kiwi guy and would best suit a rider of around 60 to 70 kg’s.

Steering is slow and stable rather than flickable – it’s got quite a raked-out front end and will fight you if you’re trying to change lines quickly. Owing to the narrow tyre section and consequent small contact patch, the bike also does not do high-force cornering very well, at least compared to modern competition. It may be significantly better than the bikes it’s modelled on, I haven’t ridden anything classic and so can’t compare.

In any crash or fall, you’re almost guaranteed to have the clip-ons dent the tank. There are the usual Honda niggles with the design, in that to get at something you first have to remove several other things. Getting the carburettor out for maintenance can be a real pain. It’s buried right in the heart of the frame and involves a fair amount of juggling to get at and then out. Remove the insulator plate first.

There are three major flaws with this bike. The first is the terribly weak front end. I’ve had the triple clamps and forks twisted out of alignment by nothing more than an aggressive gutter, and you can expect the front end to twist up as soon as any real force is exerted between grips and front wheel. The second flaw is related to the first – the headlight ears are high-zinc content die castings and these break very easily. Once broken, you’ll have to go shopping in the café racer aftermarket for replacements. Honda originals are like hen’s teeth, and for good reason.

This brings me to the third major problem: Spares. Some things are flat-out impossible to get. As an example, the carburettor mounts to the cylinder head via a phenolic resin plate, this has had plenty of time and heat to go brittle, and if broken, there aren’t any spares left anywhere. You’ll have to make your own somehow.

It may be possible to make serious performance upgrades. Apparently it’s possible to get an XR600 motor straight into the bike without modification. Certainly opening up the airbox intake and fitting a flatslide carb would liven things up considerably, as would fitting a decent aftermarket muffler… but I’d have to ask why. These weren’t performance bikes, they were never intended as performance bikes, and for the money that you’d spend on the bike plus upgrades you could get something that’d absolutely spank it in any head-to-head contest. There’s no getting around the single disc front brake, the cruiser-like steering geometry, and the narrow tyres.

They’re also getting pretty long in the tooth. Chances are high that a purchase will need some rebuilding work, owing to seals crushing up over time. I’d found the rear mudguard on my bike cracking around the mounts for the license plate. The guard is made of aluminium and vibration was getting to it.

In summary – excellent around town or for relatively gentle highway riding, but you may be in for serious maintenance including fabrication. Taller / bigger riders should look elsewhere and those seeking speed should actively avoid this bike. Great fun if you’re in the mood for small, forgiving and light, though.

Black Knight
20th May 2015, 11:57
Nice honest write up,the speed limit is 100KPH and the bike will sit on that all day.Fun bike in the twisties,especially at 100KPH.I have a 500 so a bit more power,progressive shocks front and rear have improved the handling.
You forgot to mention that they have the sexiest looking fuel tank ever fitted to a motorcycle.

OddDuck
20th May 2015, 13:24
True, but HP starts getting seriously limited if you're trying an overtake at 100 kph - I had some risky moments trying to get past trucks while touring. Lack of power for NZ conditions, speeds and average sized riders is an issue for the GB400. The GB500 is probably much more capable in this regard. Just a few extra ponies make all the difference.

ICE180
1st June 2015, 20:12
on the engine swap I did a NX650 conversion on my GB400 dynoed @ 36hp at the rear wheel much nicer for long distance riding now
youd o have to put the 400 stator in the new engine so all the electrics ran as normal
this normally will swap over very easily

jerm
2nd June 2015, 10:37
Such a fun bike. I bought one in January as my first bike and love it

chinny
9th June 2015, 20:52
Nice review, very informative. I agree with the comments that it is underpowered around 100kmph. Even as a learner I found it underpowered for overtaking. One would have to plan more than usual. Around town was great though. Although mine had an issue where it would die when starting from a standstill - apparently a common issue according to google.
Mine only had <27,000km when it was written off sadly. Sold the remains to someone who had a few for track use.
Strangely the muffler was stolen after the crash so if anyone has a original chrome GB400 muffler with 3 or 4 small holes which are patched with steel plate + rivets, leave a reply.

pkmcneil
23rd June 2015, 20:35
Yep, definitely not for big blokes. Lucky I'm not, because love these bike. They're great around town.
I agree that the 400 feels like a smoother ride chopping through the gears, but the 500 has that bit more grunt and sits at high speed better.
I've had three 400's and I'm happy with my 500. It's a keeper. I've got a 1982 GSX that I'm working on for touring.

"Mine only had <27,000km when it was written off sadly. Sold the remains to someone who had a few for track use."
And even underpowered bikes still get crashed....

313033

rambaldi
23rd June 2015, 21:02
I have seen one in the parking lot at work, I liked the visuals. They have done a couple things to the bike as well, changed the seat out and I think the pipes and the windshield.