Transalp Engine Swaps
From GummyCarbs
General Comparison
| Displacement | Torque | Horsepower | Bore x Stroke | Compression Ratio | Induction | |
|---|---|---|---|---|---|---|
| XL600V | 583cc | 55 hp @ 8000 | 38.8 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 |
Transmission Gear Ratios
| 1st | 2nd | 3rd | 4th | 5th | |
|---|---|---|---|---|---|
| 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 |
| XR750 RD07 | 3.083 | 2.062 | 1.550 | 1.272 | 1.083 |
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.
Engine Swap Details
Hawk NT650
Exhaust
- This post shows the difference in front exhaust port angles between the Transalp and Hawk engines.
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
- Thunder Dan's engine swap. He put a 2003 XL650V engine into a 1988 XL600V.
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.
EFI Systems
- Megasquirt
- Microsquirt
- Ignitech
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.