Triumph TR65 Thunderbird


Make Model

Triumph TR65 Thunderbird




Four stroke, parallel twin cylinder, OHV


649 cc / 39.6 cu in
Bore x Stroke 76 x 71.5 mm
Compression Ratio 8.6:1
Cooling System Air cooled


Single 30 mm Amal carburetor



Max Power

31.3 kW / 42 hp @ 6500 rpm

Max Torque

50.1 Nm / 5.1 kgf-m / 37 ft-lb @ 5500 rpm


5 Speed

Final Drive


Front Suspension

Telescopic fork

Rear Suspension

Dual Girling shocks, 5-way preload adjustment

Front Brakes

Single 250 mm disc

Rear Brakes

178 mm Drum

Front Tyre


Rear Tyre


Wet Weight

185 kg / 408 lbs


Length: 2220 mm / 87.4 in


1422 mm / 60.0 in

Seat Height

787 mm / 31.0 in

Fuel Capacity 

18.2 L / 4.8 US gal / 4.0 Imp gal

Consumption Average

5.2 L/100 km / 45 US mpg / 54 Imp mpg

Aimed at the economy market, the TR65 used a short-stroke version of the T140 Bonneville engine making it livelier with a better throttle response and maximum torque produced at higher rpm.

Engine performance
The Thunderbird was described as ideal for the first time big bike user and it was certainly my first big bike. As such, it fulfilled it´s function beautifully. The engine offered lively performance albeit without the torque of the 750 range which might have been somewaht intimidating. There is little to no vibration transmitted through to the rider. The 650 T-bird motor noticably lacks the instant torque of the 750 range, though, but does like to be revved and has no real attendant vibration.

The gearbox is sweet and positive in it´s changes and the clutch is featherlight (yes, really). The gearing is more than adeqaute for across -town performance and copes easily with traffic work. Third or fourth is enough although fifth is useful for faster roads although the engine never feels like it´s straining.

Carburration is by the stalwart single Amal Mk 1 whose EPA-offending tickler button meant the USA missed out on the TR65. The choke, mounted in front of the left side panel, has never been needed once the carb was tickled.

Probably because of the Lockhart item, oil consumption is negligible and the engine is and always was oil tight.

Everyone knows that these oil-bearing frames handle the best and the TR65 is no exception. the length ofthe wheelbase is a bit disconcerting as a move from a smaller bike but the lightness more than makes up for it. My tip is to have confidence to take the bike through any curve at any speed- it will get you through !

The front end like all oil-bearing frame Triumphs is ligth and when tuned- up, the bike had a tendency to perform inadvertant yet magnificent wheelies when revved from standstill !!
I replaced the fitted Avon Roadrunner with the same manufacturer´s Speedmaster Mk2 for the reason that such a light bike does not need such a big front cover, more suitable to the heavier Electro models. I find the T-bird is more nimble and brakes better as a result with the smaller front cover. The rear cover, the standard Avon Roadrunner, is retained.

I advise to set the rear drum so it is slightly less sensitive because it can lock up quick on normal pressure when what i advise you really need is the front disc brake to lead and control the braking effort. That is not to say that the drum is not a good brake- it is- but as you can control it´s sensitivity (unlike with the 750´s rear disc), then you are advised to do so.
Wet weather perfromance is excellent too and i should know having ridden in some horrendous downpours !

The wonderful progressiveness of the standard front AP Lockheed dsic brake is somewhat softer on my example although this is unusual as 750 Triumphs are less so. Nevertheless, there is plenty of feel and controlling the plot through the front and (properly adjusted) rear brakes is wonderfully easy, more so than the 750s with their grabbing rear brake.

I like the warning light panel that replaced the tachometer ...it is clear and simple and adds to the charm of what was meant to be Triumph´s economy model. The ignition switch is centralised within the panel and everything works fine. The switchgear, common througout the range, falls easily to hand and the attached gear and clutch levers are of the late dog-leg type fitted to 1982/3 Triumphs. The German Bumm mirrors and ULU indicators are excellent in performance although the one fo the latter,rear-mounted, required Loctite and proper tightening to stop it falling off whilst riding ! The headlamp is standard late Triumph and offers the same adeqaute performance although riding at night should be at a speed appropriate to the limited visibility afforded by this Lucas item.The handlebar grips were TR7T Doherty items that i replaced with the standard bulbous ones, thereby adding to the overall comfort of the ride.

I am not any sort of mechanic but changing the oilon the oil-bearing frame Triumphs is easy, adjusting the primary and final drive chains, similarly so. The popints are a different matter and forgetting to do so once rendered a long hot push back to a motorcycle shop to render their expertise !

All Triumphs are beautiful as far as i am concerned and the T-bird is no exception. All the lines work well in what is a long, slim yet sensuously curvy bike. The alloy polishes up well and the black painted / black chromed parts add, as the 1981 brochure promised, that distinctive touch from the 750 roadster range.

If you´ve never ridden a Triumph or any big bike then do start with this one. If you´re used to the Triumph 750s then you may not appreciate a delivery of power absent the outstanding torque of the bigger motor. For those used to Japanses motors, then the 650 Thunderbird is closer to your expereince with it´s rev-happy, smooth motor. All contemporary reports -Superbike, Bike, Motorcycle Mechanics, Motorcycle Weekly, Motorcycling -adored this bike, why don´t you try one and see why ?

Review of the 1983 Triumph TR 6 Thunderbird Erum Waheed