Thanks for the suggestions.
The squish clearance shouldn't change if you skim the head should it? The quench area is flat with the head surface in this application. But piston to valve clearances certainly would. As you suggested, I would definitely check piston to valve clearances with ANY...
Fortunately (or not depending on how you look at it), the BMW engine has a rather long rod to stroke ratio. A little over 2:1. I was wondering if there were any significant differences in cam timing tuning.
Because of a longer "dwell" period near TDC (piston moves slower at TDC), I've read that...
marcusaurailius, if you have a similar forum name on the Kawasaki boards, I've read your posts on shrinking the zx-9's heads. Thanks for your input.
Thanks to everyone. I think I'm just going to have to trust someone and just do it, then dyno it.
Evelrod, I agree completely about experimenting...
I've read that the best head porters stand head and shoulders above the rest. Literally, because they stand on all the trashed cylinders heads they've experimented on and didn't work.
:)
I guess my motivation to post this question here is to see if anyone felt (or had first hand experience) that modern motorcycle heads had very little area to improve in terms of porting and chamber work for more power. (Mainly to confirm my suspicions that many head builders for motorcycles are...
No. Sorry. But it seems that you keep bringing up that you wouldn't round the squish, and I wanted to make it clear that wasn;t what I meant. That's all. I understand everyone's point not to touch the quench pads itself. It's the chmaber ceiling that I'm rounding off though...
Appreciate the...
Just to be clear, because rounding the quench edge and reducing compression keeps being brought up, I highlighted the area that I meant to fill in. That'll smooth the edge without having to lose compression or quench.
http://i220.photobucket.com/albums/dd94/jcwk12r/P1030751-1.jpg
Piston is flat top, yes. And has a little dish where the combustion takes place.
With such small valve angles, 10 and 11 deg, the combustion chamber itself is rather flat as well. There's not much area to dome into. But I understand what you mean.
Here's a close up of those nasty corners and...
It may not shroud the valve if done right. Take a look at this beauty...
http://www.theoldone.com/components/cylinderheads/Honda/S2000/1ChExh21.jpg
Even my old zx-11 head looked better in the area between and lateral the intake and exhausts. Also, the valves look more deshrouded...
BTW, in regards to exhuast flow, I understand that it should be a certain percentage of intake flow. Too much and torque suffers.
Pro stock heads are around 60%.
Thanks! for taking the time to respond.
Here's the piston top. The squish area appears to correlate well with the combustion chamber.
http://i220.photobucket.com/albums/dd94/jcwk12r/P1030732.jpg
I've read of engine builders that will machine the squish tighter on the intake than the exhuast...
I realize what quench is. I am not talking about getting rid of that. But you can fill the valleys formed by the unusual square edges at the "top" of the combustion chamber.
It's not my idea, if you look at perfomance heads, you can see that they gradually build up to the squish area.
Here's...
My other question is are most modern motorcycle engines primarily a tumble type of port?
With the very straight intake port, they look like the mixture tends to shoot a little past the valve. It hurts ultimate flow, but the quality of the mixture in the combustion chmaner is good.
Too much...
It's not, I was just looking to squeeze 190hp out of the engine without having to split the cases.
The combustion chambers of performance heads I've seen are smooth. I thought that the sharp edges at prone to start detonation.
Engine stats- 13.0:1 compression ratio, 2:1 rod stroke ratio...
I have a bmw k1200r and am looking to get the head optimized. I have a spare head and looking at it the casting is pretty good already.
Valve angles are tight at 11 and 10 degrees, exhaust and intake.
The "short side" radius is nearly straight and flat into the combustion chamber.
You can see...
