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1990-1993 Yamaha SuperJet 650 Review and Specs [Video]
The first generation Yamaha SuperJet (a.k.a. SuperJet 650) debuted in 1990 to compete with the extremely popular Kawasaki stand-up jet skis. It’s hard to believe that the modern 4-stroke version of this ski is still available in Yamaha’s fleet!
If you want to find out about the very first Yamaha stand-up jet ski, this post is for you.
We at JetDrift have compiled all you need to know into this Yamaha SuperJet 650 review!
1990-1993 Yamaha SuperJet 650 Review
Although the competitor Kawasaki became popular with their stand-up jet skis, Yamaha entered the PWC market by revealing two sit-down type models, the WaveRunner 500 and the weird-looking WaveJammer.Four years later, in 1990, Yamaha introduced its first stand-up ski, the Yamaha SuperJet 650 (SJ650D). This model became one of the most popular and best-selling Yamaha jet skis of all time!
The first generation SuperJet 650 earned the nickname “square-nose SuperJet 650” due to its square-shaped bow design. This platform was pretty small too, as it was only 86.04 inches long, 28 inches wide, and 26 inches high.
With a dry weight of 287 pounds, the Superjet 650 was one of the lightest Yamaha jet skis ever built. It shared its engine and pump with the 3-seater WaveRunner III 650.The power source was a 2-stroke, 633cc, 2-cylinder engine featuring a single Mikuni BN44 carb with twin 6-petal reed valves, CDI ignition, electric start, and an industry-standard open-loop water cooling system.Thanks to these advanced features, this power mill cranked out 42 HP at 5,500 RPM while its mixed flow, single-stage jet pump provided a thrust of 385 pounds.
Since the SuperJet came without an oil injection system, owners had to premix the fuel with 2-stroke oil before the rides. In return, they didn’t have to be afraid that the oil system would fail, which could end in a seized engine.
Performance?
Contrary to popular belief, the SuperJet 650 didn’t deliver 50 HP. Although Yamaha marketed this ski with 50 HP (just like it did with the WR650!), according to the original operator’s manual, their 633cc twin engine was rated at 42 HP.
Top speed of the SuperJet 650 was about 37-38 mph in stock condition, but with some aftermarket mods, it could easily top out at 45-48 mph.
After four years of production, this model got a more powerful 701cc engine upgrade. This second-generation SuperJet, also known as square-nose SuperJet 701, utilized the same hull as its predecessor and remained in production from 1994 through 1995.
1990-1993 Yamaha SuperJet 650 Specs Chart
For your convenience, we’ve compiled the 1990-1993 Yamaha SuperJet 650 specifications into these charts!1990-1993 Yamaha Superjet 650 Engine Specs
| Yamaha SuperJet 650 | Engine Specs |
|---|---|
| Type | 2-stroke |
| Number of cylinder | 2 |
| Displacement | 633 cm³ (38.61 cu in.) |
| Bore and Stroke | 77 × 68 mm (3.03 × 2.68 in) |
| Maximum Output | 42 HP (31.5 kW)/ 5500 rpm) |
| Compression Ratio | 7.0 |
| Lubrication System | Pre-mixed |
| Recommended Engine Oil Type | Yamaha outboard motor oil |
| Gasoline and oil mixing ratio | 50 : 1 |
| Fuel | Unleaded regular gasoline |
| Cooling system | Water-cooled |
| Starting System | Electric Starter |
| Ignition System | C.D.I. |
| Spark Plugs Type | NGK BR-8HS |
| Spark Plug Gap | 0.5 - 0.6 mm (0.020 - 0.024 in.) |
| Battery Capacity | 12 V 19 Ah |
| Charging system | Flywheel magneto |
1990-1993 Yamaha Superjet 650 Drive System
| Yamaha SuperJet 650 | Drive System |
|---|---|
| Propulsion System | Jet pump |
| Jet Pump Type | Mixed flow, single stage |
| Impeller rotation | Counter clockwise (Rear view) |
| Transmission | Direct drive from engine |
1990-1993 Yamaha Superjet 650 Dimensions
| Yamaha SuperJet 650 | Dimensions |
|---|---|
| Length | 86.04 in (2,185 mm) |
| Width | 28 in (710 mm) |
| Height | 26 in (660 mm) |
| Dry Weight | 287 lb (130 kg) |
Vintage Yamaha SuperJet 650 for Sale
Unfortunately, it’s not easy to find a first-generation Yamaha SuperJet 650 for sale. Since this ski was discontinued in 1993, most of them were scrapped or went to private collectors.But with a bit of luck, you can find a Yamaha SuperJet 650 for sale on Craigslist, eBay, PWC trader, and other jet ski ad websites. Also, you may want to visit some online SuperJet forums and Facebook fan groups.
Takeaway
As a takeaway, we’ve answered the most common questions about the 1990-1993 Yamaha SuperJet 650!What Size was a Yamaha SuperJet 650?
The Yamaha SuperJet 650 was 86.04 inches long, 28 inches wide, and 26 inches high.
How Much Did a Yamaha SuperJet 650 Weigh?
The dry weight of the Yamaha SuperJet 650 was only 287 pounds. This means it weighed less than half as much as the average jet ski these days!
What Kind of Engine Did the Yamaha SuperJet 650 Have?
The Yamaha SuperJet 650 was powered by a 2-stroke, 633cc twin engine featuring a Mikuni BN44 carb, CDI ignition, electric start, and open-loop cooling.
How Much Horsepower Did a Yamaha SuperJet 650 Have?
Although the advertised horsepower rating of this machine was 50 HP, according to the official operator’s manual, the SuperJet 650 had only 42 HP.
What Was the Recommended Gas/Oil Mixture Ratio for the SuperJet 650?
The recommended gas oil mixture ratio for the Superjet 650 was 50:1.
How Fast Did a Yamaha SuperJet 650 Go?
The top speed of the Yamaha SuperJet 650 was about 37-38 mph, but with some aftermarket modifications, it could be boosted to the range of 40-49 mph.
How Much is a 1987-1990 Yamaha SuperJet 650 Worth?
It’s hard to tell the exact price of a Yamaha SuperJet 650, as it depends on various factors. Since they are less desirable than the more powerful SuperJet models, the asking prices of a nice SuperJet 650 range from $1,000 up to $2,000. But if you are looking for a side project, you can find an abandoned one for a couple of hundreds of dollars.
If you are looking for a playful vintage stand-up jet ski, you should consider a 701 SuperJet instead, as it features a more powerful engine and pump.
Many riders say that modifying a JS650 is also pointless, as its bigger brothers deliver much more horsepower and thrust out of the box. Therefore, it makes no sense to spend a fortune just to increase the performance of a stock SJ650!
