CB750F DOHC Cam question

[ArBrnSnpr]

After doing some research on installing CB900 cams on a CB750f engine (81' DOHC), I read that 81' and newer CB750F Super Sports had the same lift cams as the CB900 had.
Before I go through the trouble of sourcing CB900 cams and installing them in my bike, can anyone confirm that the CB900 cams are in fact an upgrade?

Also, I read in an older thread on this site that the only real gain would come from the installing the intake cam from the CB900.

If I'd like some more mid range performance, is this a decent direction to go assuming I can source a CB900 intake cam (from a Custom, not a CB900F) locally for a pretty good deal.

Thanks!

 

[barnett468]

After doing some research on installing CB900 cams on a CB750f engine (81' DOHC), I read that 81' and newer CB750F Super Sports had the same lift cams as the CB900 had.
Before I go through the trouble of sourcing CB900 cams and installing them in my bike, can anyone confirm that the CB900 cams are in fact an upgrade?

Also, I read in an older thread on this site that the only real gain would come from the installing the intake cam from the CB900.

If I'd like some more mid range performance, is this a decent direction to go assuming I can source a CB900 intake cam (from a Custom, not a CB900F) locally for a pretty good deal.

Thanks!

in general, whenever you install "bigger"cams, you loose bottom end but gain top end . . there is usually a trade off.

if you dont have a header yet, i would consider one of those first.

also, if your cranking compression is around 150 or less, you will gain power everywhere by increaisng your compression.

.

.

 

[ArBrnSnpr]

What are people doing to increase compression in these engines? Decking heads, domed pistons?

 

[DohcBikes]

What are people doing to increase compression in these engines? Decking heads, domed pistons?

Have you been flying the Delorean again? Think Mcfly, think.

 

[ArBrnSnpr]

Have you been flying the Delorean again? Think Mcfly, think.

Ahh shit... I know that's a movie reference, and I know it's from Back to the Future, I just can't remember back to the last time I saw the movie to make it fit this situation.

I'm guessing my question has an incredibly obvious answer, but in my defense I don't know the ins and outs of this engine and some engines respond better than others to different things. For example, you can port and polish the head in a mk2 GTI and get some decent gains, do the same work to an E46 M3 and you'll notice no positive impact.

 

[DohcBikes]

Ahh shit... I know that's a movie reference, and I know it's from Back to the Future, I just can't remember back to the last time I saw the movie to make it fit this situation.

I'm guessing my question has an incredibly obvious answer, but in my defense I don't know the ins and outs of this engine and some engines respond better than others to different things. For example, you can port and polish the head in a mk2 GTI and get some decent gains, do the same work to an E46 M3 and you'll notice no positive impact.

Basically I'm saying that the time for trending mods on that engine has passed.

Decked heads? Sure. Hi comp Pistons? Sure. All the stuff that goes allong with building a hi compression air cooled engine? Sure. Got your wallet ready?

While I do realize what we are all doing here, chasing more than ten real hp on your cb750 is only going to teach you an economics lesson. Make it run perfect at stock level first.

 

[ArBrnSnpr]

Noted. Though where this started was a question about a $30 set of cams. I'm not looking to make this a high powered race engine but if there is something cheap to buy and easy to install like a set of cams I'd be willing to do it - assuming there is a gain to be had.