Vf Engines, Need Help!

[Guest calboy13]

hey everyone,

i am looking at running a VF500 engine in a FSAE race car. i was wondering what the difference is between vf engines, other then capacity? is the capacity changed by stroke or bore size? also do the larger engines have larger ports? unfortunately, in Australia VF500 engines are few and far between so i was hoping i could get a 750 block and put a 500 crank in it? (the formula is limited to 600cc) mix and match engine parts. any advice would be appreciated , or even if anyone has an old VF engine lying around. i would happily rebuild a tired, old unit.

regards

Callum Boyce

[Kel]

The 500's are not interchangable with the 700/750's. If your limited to 600cc and will be racing others with CBR600rr motors, prepare for a lot of last places running a VF500 motor. I'd love to see a pic of the car.

EDIT: My God, if it's one of these cars...I want one BAD!

http://www.google.co...eG6bp0gH_moHACQ

[CornerCarver]

The 500 is based off of two other Honda engines. In Japan it was released in 1982 as a VF400F. When they brought to other countries without a tiered licensing system they took the bottom end from the VF400F and "fused" the heads from a pair of 250cc V-Twins to come up with the 500cc capacity. So the bottom bearing diamter is much smaller than a 750 based engine.

In the US in 1985 Harley successfully lobied for a tariff on any imported motorcycle above 700cc as they thought these large displacement "cheap" Japanese bikes were killing their sales. You could source a VF700 engine from the US sold during the tariff years. These are destroked 750cc engines. Not sure exactly how to go about further reducing capacity.

You may want to look at a Hawk 647cc or a Suzuki SV650 and destroke one of those. The SV650 shares a lot of engine architecture with the Hyabusa so top end engine speed parts are plentiful (cams, valves, injectors, etc...)

You would probably be better off sourcing a 600cc Sport bike engine. All current 600cc RepliRacer bikes are inline 4s so you wont get the torque of a v4 or v2 engine but they really scream on the top end.

Good luck.

[Veefer800Canuck]

I'm gonna recommend a late model 600 sport bike engine. The newer the better for power output.

Suzuki would likely be the most plentiful and least expensive of the bunch.

[timmythecop]

Get a crashed late 90's R6. Cheap and 200 HP per litre.

[Guest]

the FSAE rules state all teams must run a restrictor on the intake, thus most of the sports bike engines (CBR's and GSX's) are starved for oxygen in the high rev ranges and lack torque. looking for a lower revving, more torque-ish engine. alot of the teams are moving towards twin and single cylinders like aprillia's however they come at a cost

[Switchblade]

+1 SV650 de-stroke motor , cheap and plenty of parts .

[YoshiHNS]

Not sure a 500 engine would be the best option. Reliability is hit or miss with them, and they are not easily repairable if you end up with a miss.

Go with either a thumper or I4. Either one is a compromise, and both are capable of being competitive.