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Transalp Engine Swaps

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Revision as of 20:06, 14 May 2026 by Jeff (talk | contribs) (→‎Aprilia/Rotax 990)

Swap Candidates

The following engines should swap in with no modifications to the frame:

  • Honda Hawk GT NT650 (known as the Honda Bros outside the US market)
  • Honda Africa Twin XRV750 (RD04 or RD07)
  • Honda Transalp XL650V
  • Honda Transalp XL700V
  • Honda Shadow VT750 (1998 - 2013)

The Honda NT650V and NT750V Deuville motor will not swap in, because they're shaft drive. It may be possible to put the head and cylinders onto a Hawk engine. The Deuville EFI throttle bodies may be usable on a 52-degree Honda EFI conversion.

The Rotax-made Aprilia 60-degree V-twin engines might be made to fit, but will require frame modifications. To my knowledge, this has never been done.

Engine Swap Details

NT650 Hawk GT

Exhaust

  • This post shows the difference in front exhaust port angles between the Transalp and Hawk engines.

The latest Two Brothers Racing exhaust 1-1/2" at the exhaust port, 1-5/8" through the curves, 1-5/8" at the collector, to a 2" tail pipe to the muffler.

Modification

The Hawk 650 still has great aftermarket performance support. Hord Power is the best known supplier and modifier in the US. Hord Power commented on the Hawk GT forums:

The order of building hp into a Hawk goes:

Stock 47hp

Pipe/3.0 kit/pods 52hp

700 kit/cams 62hp

Stage 1 heads 67hp

Stage 2 heads 72hp

Flatslides +5hp

Stage 3 heads 80+hp and $$$$$$$$$$$$$$$$$$$ and other $$$$$$$ stuff to make it "reliable."

XL650V

XRV750

Transalp Friends Germany has details of fitting an XRV750 RD04 motor into a 1988 XL600V Transalp.

VT750

The 52-degree, chain-drive VT750 engine uses an inline crank pin, as opposed to the offset crank pins in the XL600V Transalp. This makes the VT750 sound more like a Harley Davidson, which uses a 45-degree engine with a single-pin crankshaft.

Comparison of the VT750 and XL600V crankshafts

Skyliner on AdvRider says the 1993 - 2013 VT750 will bolt directly into a Transalp frame (Mar 25, 2024). Details:

  • Transalp or NT650 camshafts fit
  • Uses internal oiling, so 1991 NT650 heads fit, as well as Transalp 650 and Deuville heads. This allows Transalp 650 or XRV headers to fit.
  • Ignition pickup is different.
  • Gear shift shaft is shorter than the Transalp

Additional information from Skyliner about the clutch, firing order, cylinder heads, and exhaust (Feb 20, 2022). This post covers cooling plumbing and FCR carburetors.

Aprilia/Rotax 990

The Rotax 990 engine used in various Aprilia 1000 models might conceivably be made to fit into the Transalp frame. If so, it will definitely require custom mounting brackets, and may require the complete removal of the lower cradle from the frame. Aprilia uses the Rotax engine is a stressed member.

Hawkati on the Hawk GT Forum has fit an Aprilia Mille (Rotax 990) engine into a Hawk GT frame. There is a Youtube video showing the engine roughly fitted into the Hawk GT frame. Here is a link to the entire video series.

  • The rear, top bolt fits nearly identically. (This corresponds to the upper mounting lug on the NT650 Hawk and XRV750 Africa Twin engines that's missing on the XL600V Transalp. The fitment is shown at 0:58 in the video)
  • The front sprocket was 7mm high, requiring the engine to be tilted forward. (Explained at 1:27 in the video)

EFI Conversion

Rather than trying to source and/or tweak carburetors, it's probably best to use one of the aftermarket EFI systems that are now on the market.

Examples

These guys adapted Honda Deauville fuel injection to a Hawk GT motor.

EFI Systems

Throttle Bodies

The 2003+ SV650 uses 39mm throttle bodies. The 2017 model's throttle bodies are redesigned and "slimmer", according to Wikipedia.

The NT700V was sold in the US. It had 81x66mm bores with a 10:1 compression ratio, producing 65hp at 8000 RPM and 48.8 lb-ft of torque at 6,500 RPM. It's in the same 52-degree V-twin family as the Transalp, Hawk, and Africa Twin. Its throttle bodies are 40mm with 12-hole injectors. It appears that the NT700V used a fuel pump that provided something like 45 - 50 psi.

Specification Comparison

Displacement Horsepower Torque Bore x Stroke Compression Ratio Induction
XL600V 583cc 50 hp @ 8000 39.1 ft-lb @ 6000 75x66mm 9.2:1 2x32mm Keihin CV
NT650 647cc 56.1 hp @ 7897 43 lb-ft @ 6053 79x66mm 9.2:1 2x36mm flat slide carburetor
XL650V 647cc 52 hp @ 7500 40 lb-ft @ 5500 79x66mm 9.2:1 2x34mm flat slide CV
XL700V 680.2cc 59.1 hp @ 7750 44.3 lb-ft @ 5500 81x66mm 10.0:1 EFI 40mm throttle bodies
XR750 RD07 742cc 62 hp @ 7500 46.2 lb-ft @ 6000 81x72mm 9.0:1 2x38mm flat slide CV
VT750C 745cc 43 hp @ 5500 44 lb-ft @ 3000 79x76mm 9.6:1 2x 36mm CV
Aprilia ETV1000 997.6cc 98 hp @ 8250 71.5 lb-ft @ 6250 97x67.5mm 10.4:1 EFI 47mm throttle bodies

Transmission Gear Ratios

1st 2nd 3rd 4th 5th 6th
XL600V 2.571 1.777 1.380 1.125 0.961
NT650 2.769 1.882 1.450 1.174 0.965
XL650V/XL700V 2.500 1.722 1.333 1.111 0.961
XRV750 3.083 2.062 1.550 1.272 1.083
Honda VT750C 2.4 1.55 1.174 0.960 0.852
Aprilia Tuono 2.26 1.63 1.3 1.09 0.96 0.88
Aprilia Caponord ETV1000 / Falco SL1000 / Futura RST1000 2.5 1.75 1.368 1.091 0.957 0.852

The XRV's first gear is 20% lower, second is 16% lower, third is 12% lower, fourth is 13% lower, and fifth is 12% lower.

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