1983 Honda CB750 Nighthawk from United States of America
A fast, fun, multipurpose street bike with a fantastic engine and an abysmal charging system
ALTERNATOR ROTOR - I've had to replace the alternator rotor twice since I've owned it to the tune of $300 a pop. I've been told these were particularly prone to failure on this bike, and that has certainly been my experience. The alternator output is also absolutely pitiful (even worse than most bikes). It really can't be driven around at less than 4000RPM or the battery will discharge. Cruising around town is not very pleasant in second gear at an unnecessary 4000+RPM, and the only time it seems to really bring the battery up to an acceptable level is when the bike is driven at sustained high speed (75+MPH). The rotor failures and charging problems are primarily why I rated the bike so low in reliability. Every time I ride it, I half expect it to quit charging, and for the battery to be half drained when I get where I'm going. The electrical problems have caused me to lose trust entirely in the motorcycle for long trips. The bike has a lot of good points, but they don't mean a thing if you can't get the blasted thing to start after driving it across town.
BATTERY - Replaced many, many times. The constant mediocre charging is hard on batteries, and both times the rotor failed, the battery was discharged enough to kill it. If the bike had had a voltmeter or warning light, the battery might have been saved and I might not have been left stranded alongside the road.
STARTER CLUTCH - Replaced this winter. This has been another ongoing misery more or less ever since I bought the bike. I actually took it in to get it fixed in about 2005, but they couldn't seem to get the job done and it started the same horrid chattering the following year. I finally got frustrated and just replaced it myself this year. I found a good used assembly to install, but Honda wanted $400 for the new parts.
FUEL PETCOCK - I had the fuel tank petcock replaced to the RIDICULOUS tune of $110 (part only). There is nothing at all to them, but they sure are expensive. I had fixed the old one myself (and it was JUST FINE), but when I had the bike into the shop to (not) get the starter clutch fixed, the mechanic saw the petcock was modified and refused to release the bike without replacing it. Thanks pal... That was (and will likely remain) the last time anyone else worked on the bike.
ELECTRICAL - I've had various electrical/wiring problems, most originating in the wiring inside the headlight.
FRAME- I had an upright (frame tube) crack CLEAR THROUGH and had to weld in a patch. It was near one of the front motor mounts. I don't have a clue why it cracked.
CARBURETORS - I rebuilt the carbs this year because they badly needed it and one of the transfer tubes had developed a TORRENTIAL leak (think 15MPG!). Of course the manual I have for the bike specifically says not to separate the carbs (take it to the dealer naturally), but I don't know what they expect to become of the O-rings sealing the transfer tubes. They disintegrate like every other rubber piece in the carbs. Anyway, not the bike's fault, just standard maintenance, but the carb parts are all absurdly expensive.
CHAIN - Replaced when I bought the bike.
BRAKE CALIPERS - The left caliper was sticking so I disassembled and cleaned it and flushed system. I will fully rebuild both calipers before the 2010 riding season.
CABLES - The choke, clutch, tachometer, and both throttle cables have been replaced at some point since I've owned the bike. The clutch cable has been replaced twice.
CRANKCASE BREATHER - The stock design was complicated and some of the rubber parts were very rotten. I replaced the whole mess with a simpler breather system using various bits I had around. It works fine.
BRAKE LININGS - Replaced both front and rear linings when I bought the bike. I will probably replace them again when I rebuild the calipers this year.
SEAT COVER - Replaced about 2004.
Tires - Replaced when I bought the bike. The rear has been replaced twice since I've owned it.
FORK SEALS - The left fork seal started leaking last year and both will be replaced this year. I'm planning on installing progressive front springs at the same time.
CLUTCH - The clutch is starting to feel a bit weak and might need to be replaced this year or next.
OIL LEAKS - The shift lever seal leaks a bit, but it's not too bad, so I'm not in too big a hurry to fix it.
For the record, the gauge cluster was missing when I bought the bike, so the actual mileage is unknown. I replaced the gauges when I bought it and have put about 20,000 miles on it since I've had it.
The best aspect of this bike is the engine. It runs wonderfully and pulls like a freight train all the way to redline. I did install pod filters, a jet kit, and modified the exhaust baffles which did make a significant improvement in power (particularly on the top end), but it ran pretty darn well in stock form. There are of course many MUCH faster machines around today, but given the age, displacement, and considerable weight of the bike, it is surprisingly fast and a heck of a lot of fun to slingshot out of a curve or launch off a stoplight. Throttle response is instantaneous, and the power is smooth, but seems to build exponentially as RPM increases. The re-jetting and filters really opened mine up on the top end, and now it pulls the hardest right at redline. I wish it had another 1000RPM available. It's a modification I would highly recommend if one has a little experience in carb tuning.
The handling is pretty good, probably great by 1983 standards, but naturally it could be better when judged against more modern machinery. The frame is not the most rigid, and the front fork seems to have a bit of flex in it as well. It really needs progressive springs as it likes to dive and bottom out when set for a reasonable ride, and rides like a buckboard when the air pressure is increased. I've also experienced a bit of wobble on a couple occasions when leaning hard through a fast curve, which was rather frightening. However, it hasn't seemed to do this since I did the frame repair, so that may well have been the sole cause.
The ergonomics are alright but not great. The seat is fairly comfortable, but it's too wide in the front for shorter riders. I'm 6' and still wish it was a bit narrower. The foot clearance in the shifter area is also poor. My toe always rubs the engine in front of the shifter, and the shifter is difficult to get solidly on or under as a result. It is particularly irritating when wearing big heavy work boots. I'd like the footpegs and shifter moved back about 2".
One complaint I do have it that there is almost no storage on the bike. The only compartment is under the seat accessed through the left side cover, and it is TINY. It's good for your insurance card and a pair of glasses, and that's about it.
I guess the only other thing I have to say about the bike is that it has a tendency to miss second gear when shifting fast if the shifter isn't just ripped upward. This is made worse by the tight clearances with the shift lever and the engine.
Would you buy another motorcycle from this manufacturer? Don't Know
Review Date: 5th December, 2009