Using a 'Busa engine for a Desert Buggy. . .

Guys I'm new to the forum but not new to sportbikes. . .just 'Busa's (I have an '02 R1, an '00 R6 track bike project, and an '01 Aprilia RS50 funbike. . .and had an '02 GSX-R750 until it got stolen from me!!!)

Anyway I need some info on hopping up the 'Busa engine. . .here's what I'm doing. . .I am building a 2-seat mid-engine/rear wheel drive desert racing buggy and I plan on using a Hayabusa engine/tranny with a Jeffco Reverse Differential ( this allows me a tighter turning radius and gives me a reverse gear which required by the rules. . .the class that I am building to (SCORE Class 10) allows me to use any engine (not just motorcycle) as long as it didn't displace more than 2000cc in stock form. . .for a 2-seater w/a fuel injected engine I am restricted 1750cc (don't know if the 'Busa can be made that large or not???) and my throttle body size is restricted 58mm. . .the stock intake manifold and throttle bodies must be retained, but they can be port matched (no more than 1/4" deep porting though). . .fuel injectors are open as are internal parts. . .but no turbo or superchargers. . .

Those of you in the 'Busa know what modifications would you suggest to a 'Busa engine for this type of build. . .this thing is going to be used off-road in 4-8 hr. endurance events (potentially longer) so reliability will be important as well as power to weight ratio. . .I think I can keep the buggy in the sub-2000 lb realm (I have seen one 'Busa powered buggy that weighed in at 1650 lbs without driver and co-driver). . .

. . .I also wouldn't mind know which companies are reputable for the mods and which ones to stay away from. . .

Thanks for your help!!!


Foghoon Leghoon
Donating Member
:welcome: To the ORG
The experts and pic police will be by shortly.
We need pics, any pics:rulez:
Ride that buggy safe!
I'm working on the pic's. . .I was gonna post up some pic's of the buggy that I have already seen with a stock 'Busa engine in it, but the website is down. . .sorry!
Most of them are running 1600cc air-cooled VW engines. . .so I can't imagine that they are making that much HP. . .I did some looking and the only buggy that I could find power specs for in this class was making 155 HP and 149 lb-ft. of torque for an ~2000 lb. buggy. . .the class 5/1600 Baja Bugs (Beetles) make way less than that. . .around 80 HP. . .so I think I would want more than the stock HP especially since the 'Busa engine's torque isn't going to be as high as the VW engines are. . .

. . .I don't want to have to tear it down after every race. . .lets say the average race would be 200-400 miles (I can't see myself racing in any event longer than that at this point in time). . .if I can get 2000 miles before HAVING to tear it down without losing performance that would be GREAT. . .being able to go longer than that would be even better!!! I don't mind having to replace clutch plates after every race as long as they last the entirety of the race. . .

. . .what would I be concerned with to need to tear this engine down more than once a season. . .I know riding my streetbike on the street is way different, but these newer 4-stroke, EFI sportbike engines seem to be pretty reliable. . .I know hopping them up produces new and unintended stresses etc. . .but does the 'Busa have a known weak link that I should know about???
:welcome: To the ORG
The experts and pic police will be by shortly.
We need pics, any pics:rulez:
Ride that buggy safe!

Here's some pic's of the buggies that are very similar to what I'm working on and that I would be competing against. . .

. . .the black one uses a Hayabusa engine. . .and weighs in at 1650 lbs while the silver/grey one uses a GM Ecotec 4 cylinder and weighs in at well over 2000 lbs. . .IIRC 2450 lbs. . .

. . .these two buggies are both built by shops that sell them as turn key. . .

SpeedUnl MC10.jpg

Fusion C1 Lite.jpg


Lily's Daddy
or you could go with one of these v8 hayabusa motor
it uses two Suzuki Hayabusa engines, making it a 2800cc, 455 horsepower V8! Engineered by Powertec, the V8 is mated to a six-speed paddle-shift gearbox and will give you 30 hours of use between rebuilds



That's really cool (as well as probably REALLY freaking expensive), but the rules only allow a max of 4 cylinders. . .

. . .I think I remember seeing that in a magazine article somewhere. . .I think it was in a kit car magazine. . .


Hayabusa Immortal
Staff member
Some things off hand you might want to consider.

A Gen 2 (08-09) engine will make more power due to dual injectors, changes in the head, cam profile, 1340-vs 1300cc (longer stroke) It also has a bigger output shaft than the GEN1 bike. The output shaft is a problem in other car applications. I wouldn’t even consider trying it with a stock Gen1 shaft. Since that requires splitting the cases, it makes the argument better for the Gen2. The shaft diameter of the Gen2 falls in between the Gen1 and the aftermarket Gen1 replacement. I haven’t heard of the shafts breaking in the Gen2 but I haven’t kept up with it closely. The Gen2 sprocket selection is more limited.

Boring the busa engines to 1397(gen 1) or 1441 (gen2) seems to be a very reliable mod. Going beyond that or longer strokes have caused some longevity issues to some bikes.

With that kind of weight I would think you would need a lockup clutch to improve clutch life.

Even with a stock 1340 gen, you should be putting out more power than what you are quoting from your class… with less weight.

I’d buy two Gen 2 engines and build the buggy with a stock engine and see where you are. If it is completive as is, you have a ready to drop in spare. If you need more hp, have the needed work done on the 2nd engine while you still can work out the chassis bugs etc.

If you can be competitive with a stocker, you will be much better off.
Buy two wrecked bikes so you have all the parts needed. Harness, ECU, Fuel pump, sensors, Airbox, etc. Sell off the excess parts to make it hurt less.


Hayabusa Immortal
Staff member
Big bore Hayabusa
270 HP Hayabusa Big Stroker
[]Hayabusa Big Bore 1397cc Cylinder/Piston Kit

[FONT=Arial, Helvetica, sans-serif]SHOGUN 1525cc[/FONT]

[FONT=Verdana, Arial]Hayabusa 99-02 1585cc Big Bore Kit

I'd be surprised if those 1450+ engines would last for 2000 of hard racing a buggy would put on it.
Professor. . .thanks for the comments. . .very informative and helpful. . .just the kind of info that I was looking for. . .especially with the Gen 1 vs. Gen 2 output shaft. . .that is a definite area of concern for me!!!

and the clutch as well. . .there is a guy with an RC51 powered UTV and he is eating clutch plates as well. . .

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