Topic: CB750 F2 - race engine

[dakota]

Hi,
we have a CB750 F2 1978 and we would like to build a racer.
We aren't going for the bigborekit and decided to stay on 734cc.
These are the modifications that we already have planned tot do.
What can we still do to get a "fast" bike?

- seals,o-rings, ...
- electronic ignition
- camshaft 41a or ...
- racing cam tensioner + chain + adj. cam sprocket
- primaire chains + tensioner
- titanium retainers
- bronze valve guides
- heavy duty valve springs
- heavy duty cilinder studs
- valves?
- rods?
- porting the head
- lightening the crank

perhaps (not for the first races)
- keihin cr
- nova close ratio gearbox

thanks

[voxonda]

Hey Dakota,

Most of the thing you mentioned aren't going to make the bike any faster. But are a good choice to make it (even) more reliable.
Building a race bike isn't just about the amount of power, you will have to be able to 'put' it on the street/track as well. Most power is made in the cylinder head. If you want torque you should go big bore. But from what I have experienced with my bike during demoraces including the 3hour of Oss is that no matter what power you have, the rider is the most important factor. We've raced a 'good' F2, just new rings, carefully build engine, 41a Webcam, good ignition, race clutch and special prepped FD carb's and a good pipe!
There where some younger, in theory, faster bikes that could not stay with us, neither in corners nor in straight line speed. Although there is still a lot to gain, the engine seem to be very reliable. Havent touched it after the 3 hour beating.

Cheers, Rob

[bear]

Most of the thing you mentioned aren't going to make the bike any faster. But are a good choice to make it (even) more reliable.
Building a race bike isn't just about the amount of power, you will have to be able to 'put' it on the street/track as well.

Cheers, Rob

I'm with Rob.
If you want a fast road racer get it to steer, stop and dig it's toe's in.

Cheers,
Brian

[voxonda]

Hey Dakota,

Do not let us discourage you. No intention for that, but seen a lot over the years. Highly tuned engines blowing and or crashing out first time out. It is about the total package.
 

[Jerry Rxman Griffin aka MuthaF'er]

+1 on what you've just heard. And possibly up the compression, bigger cam than the 41A with some serious head work.

[voxonda]

Do not forget to addept the pistons if using another than the 41a! Need to adjust the pockets.

[dakota]

Hi,
Thank you for the replies.
After these replies we aren't at all discouraged, but now we know what we can expect and what we have to do to get a reliable engine.
- ignition
- 41a cam
- segments
- oil cooler
- seals, o-rings, chains,...
We're going to start with these modifications and then focus on the frame and aerodynamics.