Topic: Cb750f camshaft in k8 engine

[Dime]

In an ideal world I would drop a Webcam bolt in cam or similar into my k8 when I am doing the top end. However the f cams can be had alot cheaper when they come up.

With a ported head is the f cam worth doing in my k8 engine? Or just get the head ported and skip the cam for now?

This is based of a 836cc engine.

Thanks

[HondaMan]

Like a lot of things, it depends...on which "F" engine you're mentioning.
The F0/1 had the same cam timing as in the K0-K5/6 bikes, 5 BTC intake opening, 35 ABC closing intake. In the F2 and all later ones the intake changed to 0 BTC intake opening and 40 ABC closing, which caused the powerband to shift upward (and narrow a bit) and required carbs with better-controlled idle circuits to prevent intake spitback troubles and resulting poor idling situations (especially when hot).

So, it depends on which "F" cam you get?

The F2/3 cams also had slightly more lift (almost 0.5mm more on intakes), which was part & parcel with the more-efficient intake valves of the F2/3 heads. I have approximated that same efficiency with the earlier valves (and the K7/8 versions) by trimming the lip off the faces, but this reduces their ability to resist rusting over time when sitting too long. The valves themselves don't swap, as the F2/3 valves use different retainers from the "K" versions (among other reasons). There are aftermarket solutions to some of these issues, but require large bankrolls to employ. 

[Jerry Rxman Griffin aka MuthaF'er]

The K7 and K8 engines are basically derived or the same as the F0 and F1 engines. -392 engines.

With this being said, "when they come up", how will you actually know which cam you get unless you take it out of a known unmolested engine. They all look the same and do not have identifying markings like aftermarket cams do.

[scottly]

Or just get the head ported and skip the cam for now?

This is based of a 836cc engine.

Thanks

Even a mildly ported head will give more power increase than any cam alone.

[newday777]

I don't have an answer to your question on the F cam.
You mentioned Webcam, I have a new unopened Webcam 41a/CX2 cam available if that is what you want.
I'd let it go for $275 plus shipping.

[Dime]

Like a lot of things, it depends...on which "F" engine you're mentioning.
The F0/1 had the same cam timing as in the K0-K5/6 bikes, 5 BTC intake opening, 35 ABC closing intake. In the F2 and all later ones the intake changed to 0 BTC intake opening and 40 ABC closing, which caused the powerband to shift upward (and narrow a bit) and required carbs with better-controlled idle circuits to prevent intake spitback troubles and resulting poor idling situations (especially when hot).

So, it depends on which "F" cam you get?

The F2/3 cams also had slightly more lift (almost 0.5mm more on intakes), which was part & parcel with the more-efficient intake valves of the F2/3 heads. I have approximated that same efficiency with the earlier valves (and the K7/8 versions) by trimming the lip off the faces, but this reduces their ability to resist rusting over time when sitting too long. The valves themselves don't swap, as the F2/3 valves use different retainers from the "K" versions (among other reasons). There are aftermarket solutions to some of these issues, but require large bankrolls to employ. 

I was referring to the f2/f3 cam. I feel like my better money spent is to have someone rebuild the head and port it as well leaving the cam for a down the road upgrade.

[Dime]

The K7 and K8 engines are basically derived or the same as the F0 and F1 engines. -392 engines.

With this being said, "when they come up", how will you actually know which cam you get unless you take it out of a known unmolested engine. They all look the same and do not have identifying markings like aftermarket cams do.

True I think it would be trusting the listing which is a roll of the dice

[Dime]

Or just get the head ported and skip the cam for now?

This is based of a 836cc engine.

Thanks

Even a mildly ported head will give more power increase than any cam alone.

This makes sense. I am assuming that the head has to be rebuilt anyway so porting is the logical step even with stock cam.

[Dime]

I don't have an answer to your question on the F cam.
You mentioned Webcam, I have a new unopened Webcam 41a/CX2 cam available if that is what you want.
I'd let it go for $275 plus shipping.

That is an amazing offer. If I had the cash on hand I would take you up on that offer. Unfortunately I do not. Thank you