The Turbo owes a large part of its sporting appeal to its body pieces; the 650 shouts styling and function even when it's standing still.
The stylized "tank" is actually a plastic shell reminiscent of the old John Player Norton; under the shell lies a steel 4.
1-gallon fuel tank.
The Turbo's 42.
2 mpg average is down significantly from the Seca's 47.
5 mpg average, but the bike will carry you a respectable 175 miles before it draws fumes.
The Café-style riding crouch is nearly ideal.
A couple of our testers thought the handlebar was just a touch too low; otherwise we all loved the positioning.
The seat itself, however, drew more than a few grumbles; the foam is too firm and too thin, and the saddle is too narrow for comfort.
The fairing, however, is commendable.
Only the outside half of your hands and the top half of your helmet are in the breeze.
The mirror location could be improved; it's impossible to see directly behind the bike, which is bothersome if not actually dangerous.
The Yamaha XJ650LJ shows that progress can be made on the Turbo concept; it is less complex than the Honda Turbo, and in many ways, specifically in the sporting sense, it offers better overall function for the average rider.
This is not to say, however, that turbocharging is the Ultimate Answer for the canyon crowd.
Both Turbo bikes are heavier than 1100cc sport bikes and offer quarter-mile performance only on par with normally aspirated 750s.
And, unfortunately, both are saddled with the dreaded curse of Turbo Lag.
As they now exist, turbocharged bikes are rolling platforms for expressing new, advanced ideas.
The name Turbo immediately lends validity to other new ideas (such as a truly functional seating position) that might otherwise have been overlooked by an image-conscious public.
We welcome these new Turbo bikes for the functional advantages they bring to sport bikes.
I remain less than enthusiastic about turbocharging for the sake of increased engine performance.
The XJ650 Turbo's power train has been strengthened in a number of areas.
The clutch's torque capacity was raised through the substitution of Seca 750 clutch springs.
These are nine millimeters longer than the standard 650 springs.
All gear ratios remain the same as in the standard 650, but a number of deep-engine gears-including fifth-have received an improved heat-treatment which makes them more durable.
And the final drive now has a rubber shock cushion to ease the peak loads applied at the rear wheel.
According to Yamaha's tub-thumpers, the reed valve arrangement in the Turbo's airbox partition "largely eliminates turbo lag.
" Actually, it doesn't, because the turbocharger's inability to deliver air instantly when it is needed is only one of several components of turbo lag.
Another is the lower compression ratio used with turbocharging, which diminishes an engine's power under no-boost/low-boost conditions.
Honda reduced the CX500's compression ratio a lot and the CX500 Turbo (for that and other reasons) is afflicted with a lot of turbo lag.
Yamaha opted for less maximum boost, a smaller reduction in compression ratio, and suffers correspondingly less.
But the reduction is there, along with the reduced valve overlap and a considerable surplus of weight, and all these things make up a dose of turbo lag.
You have only to ride the Yamaha Turbo to know it's there.
The 650 Turbo requires quite a bit of coaxing at the starter button to fire up; hot or cold, the Seca is a markedly reluctant starter.
Once it finally starts, the Yamaha is ready to roll after only a short warm-up period.
At low speeds and around town the Turbo feels satisfactorily peppy; the retuned 650 engine gives away surprisingly little to the standard 650 Yamahas, and it is much stronger down low than the Honda Turbo.
This is not unexpected; the Turbo Seca displaces a healthy 150cc more than the CX-TC.
As you dial up throttle, the Seca responds with a smooth, progressive power delivery; it has decent mid-range, and when cruising it feels about average for a 650.
But at about 6000-plus rpm all you have to do is crank in full throttle and the Turbo rockets away; when the tur-bocharger is pumping, there's nothing "average" or "650-like" about the Seca.
The stylized "tank" is actually a plastic shell reminiscent of the old John Player Norton; under the shell lies a steel 4.
1-gallon fuel tank.
The Turbo's 42.
2 mpg average is down significantly from the Seca's 47.
5 mpg average, but the bike will carry you a respectable 175 miles before it draws fumes.
The Café-style riding crouch is nearly ideal.
A couple of our testers thought the handlebar was just a touch too low; otherwise we all loved the positioning.
The seat itself, however, drew more than a few grumbles; the foam is too firm and too thin, and the saddle is too narrow for comfort.
The fairing, however, is commendable.
Only the outside half of your hands and the top half of your helmet are in the breeze.
The mirror location could be improved; it's impossible to see directly behind the bike, which is bothersome if not actually dangerous.
The Yamaha XJ650LJ shows that progress can be made on the Turbo concept; it is less complex than the Honda Turbo, and in many ways, specifically in the sporting sense, it offers better overall function for the average rider.
This is not to say, however, that turbocharging is the Ultimate Answer for the canyon crowd.
Both Turbo bikes are heavier than 1100cc sport bikes and offer quarter-mile performance only on par with normally aspirated 750s.
And, unfortunately, both are saddled with the dreaded curse of Turbo Lag.
As they now exist, turbocharged bikes are rolling platforms for expressing new, advanced ideas.
The name Turbo immediately lends validity to other new ideas (such as a truly functional seating position) that might otherwise have been overlooked by an image-conscious public.
We welcome these new Turbo bikes for the functional advantages they bring to sport bikes.
I remain less than enthusiastic about turbocharging for the sake of increased engine performance.
The XJ650 Turbo's power train has been strengthened in a number of areas.
The clutch's torque capacity was raised through the substitution of Seca 750 clutch springs.
These are nine millimeters longer than the standard 650 springs.
All gear ratios remain the same as in the standard 650, but a number of deep-engine gears-including fifth-have received an improved heat-treatment which makes them more durable.
And the final drive now has a rubber shock cushion to ease the peak loads applied at the rear wheel.
According to Yamaha's tub-thumpers, the reed valve arrangement in the Turbo's airbox partition "largely eliminates turbo lag.
" Actually, it doesn't, because the turbocharger's inability to deliver air instantly when it is needed is only one of several components of turbo lag.
Another is the lower compression ratio used with turbocharging, which diminishes an engine's power under no-boost/low-boost conditions.
Honda reduced the CX500's compression ratio a lot and the CX500 Turbo (for that and other reasons) is afflicted with a lot of turbo lag.
Yamaha opted for less maximum boost, a smaller reduction in compression ratio, and suffers correspondingly less.
But the reduction is there, along with the reduced valve overlap and a considerable surplus of weight, and all these things make up a dose of turbo lag.
You have only to ride the Yamaha Turbo to know it's there.
The 650 Turbo requires quite a bit of coaxing at the starter button to fire up; hot or cold, the Seca is a markedly reluctant starter.
Once it finally starts, the Yamaha is ready to roll after only a short warm-up period.
At low speeds and around town the Turbo feels satisfactorily peppy; the retuned 650 engine gives away surprisingly little to the standard 650 Yamahas, and it is much stronger down low than the Honda Turbo.
This is not unexpected; the Turbo Seca displaces a healthy 150cc more than the CX-TC.
As you dial up throttle, the Seca responds with a smooth, progressive power delivery; it has decent mid-range, and when cruising it feels about average for a 650.
But at about 6000-plus rpm all you have to do is crank in full throttle and the Turbo rockets away; when the tur-bocharger is pumping, there's nothing "average" or "650-like" about the Seca.