cylinder block mill

Would milling the cylinder block on a 1015cc increase performance due to the new deck height/squish band? Cuz I really want this bike to rip/fly. I need the head to flow some air regardless of valve size! Then I can play cam timing all day with bumps to the exhaust valve closing time. Any thoughts on grinding the valve head diameter? Does this increase flow?

That's a lot of questions.
Decking the head will increase compression by reducing the space above the piston, reduce piston to valve clearances, possibly affect cam timing. Not sure what the accepted level of decking is. Someone more experienced will have to answer that.
What cams are you running? I would think cam lift would affect the amount that can be decked.

I need to know how a racer sets the deck height and the optimum squish band. In other words how far out of the top of the jug do you want the piston? If at all? Someone on here stated the diff between a average motor and a fast one is the diff between standard squish and optimised . So why doesnt anyone seem to know this?

What is the secret here? Excuse me if this has been hashed. I don't remember anything like answers or useful info on the topic at all. Just a bunch of "you gotta calc this and watch that and .... I wanna know what will make this motor quick. There is no magic. Just facts and people have been holding back. Someone needs to break into the kz vault and grab me the s file. And dont'
bring any of those goons

Now watch, here comes the valve clearance goons again. Eternally warning you of valve to valve and piston to valve clearance, shaking their fingers into your face. You just want to bite the finger off, like that? We also don't need the combustion chamber gang. The ones who believe it's inevitable like California sinking , that the piston will "eventually hit head" 100rev's, 100yrs? Just that at some point, bam. No way to stop it. So we know whose invited to the party people with something to say.

Rather than trying to explain this myself, I'll link a couple of articles that I found on the internet:

www.gasgasrider.org/html/measuring_squish.html

www.motorcycle.com/how-to/wrenching-with...ion-3420.html?page=2

Just use these techniques to measure your current squish clearance, and then adjust by milling the head or block. Then you need to recheck piston to valve clearance and make sure that you have 0.080" on the intake valve and 0.100" on the exhaust valve. This might necessitate milling the pistons to achieve the desired clearance.

Also note that your camshaft timing will be affected by cutting the head or block.

The optimum squish distance is one that allows the piston to lightly kiss the head under the worst conditions.

The ability to build a motor that does that is the difference between a real engine builder and an amateur.

What people normally do is calculate the specs to allow the piston to lightly kiss the head, then allow 0.035" to 0.040" for safety.


No guts, no glory

Thank you two for the replies, good repllies! Love it. Now that's something I could use

nads.com wrote:

Cuz I really want this bike to rip/fly. I need the head to flow some air regardless of valve size!

I remember I researched flow techniques a long time ago and was amazed at how complicated it is. Also, bigger is not always better. The whole system has to be tuned to sing together to get best flow. There was a case shown where somebdoy increased valve size in an attempt to make the engine "breathe better" and they actually reduced the power because it screwed up the flow match. It seems like it is a black art and some people know how to do it but most people don't.

nads.com wrote:

I need the head to flow some air regardless of valve size!

get yourself a nice box and pack it up real nice and send it to larry or ape.

some things are just best left to the experts.

kawsakiman wrote:

nads.com wrote:

I need the head to flow some air regardless of valve size!

get yourself a nice box and pack it up real nice and send it to larry or ape.

some things are just best left to the experts.

x2.....kinda like shopping in new york...if ya gotta ask how much....get to stepping.......if you havent a clue...send it out......

Well thank to the people who replied, it's nice when u get straight answers like BAM! I'm sending the head to Larry soon to see what the port job has done. And you all can see too. I'm just trying to get a little more out of this motor and it will be something to keep up to the rockets. I've seen what they all can do and I'm close. The big ones are gonna get me every time but I just know I can run them hard if I get about 20hp more out of carbs and good flow with the right cam timing. I don't know much about porting but I have a feeling it's all in the velocity, to a point. I'm not concerned with having to turn high rpm to make this power, it has to be done this way. I need the cylinders to increase charge as far up the band as I need to go. I'm looking at 75000 to 10000 being the engine speed where It pulls like a tractor. I'm thinking around 35 or 40 thou for the squish, have to see what it is currently, and work from there. I'm gonna start ripping it down and this time, THIS time it's gonna be faster. I know that no old head can flow the air of a four valve motor and that's the biggest clue that the ports need alot of work. That's been done. Now I'll know how this head will respond to what I've done to it. The leave it to people who know thing has never applied to me Not me, Ill make this work one way or another I set my own rules, make my own game. I'm gonna prove once and for all the low end torque thing is for grandpa's and it's the easy way out for a certain riding style. Stop light to stop light is meaningless to me. What would I do on the open road? I'd look down it with longing, wishing I could take the distance with power and authority. Funny thing is about head porting u hear alot of numbers and see some cloudy pics and more hype, but never any actual "This is what I did to increase flow." To me beating people around the bush means nothing, so I'm stepping up to the plate myself. I don't learn the hard way, I never learn. I win. State of mind. And a good one is all you need. It's not about the dollar to me it's about ability to take something and make it work without all the tools. Only need to know what the tools do and I can figure somethig out.

why don't you just bore it and get some 10.25:1 or 12.0:1 pistons. Then run bigger valves and port the head? That will make a huge difference. If you Mill the Head it's gone forever. Otherwise you can always go back down on compression by just a piston swap.

And I might add,; be sure to watch for piston to valve, valve to valve, and piston to head clearances. :laugh: