Combustion chamber volumes

[Volker_P]

Fine detail pictures. However in the last picture the intake port looks like it has been cleaned with a sharp tool. Especially at an outer knee surface like here, I think one should rather leave it as it is than doing it this way. I suppose you can you blame the previous owner for doing that?
Guess it's worth to smoothen this surface again.

[pae]

Fine detail pictures. However in the last picture the intake port looks like it has been cleaned with a sharp tool. Especially at an outer knee surface like here, I think one should rather leave it as it is than doing it this way. I suppose you can you blame the previous owner for doing that?
Guess it's worth to smoothen this surface again.

I know. I'm a bit of a perfectionist, so I will be smoothing them out before I finish grinding the seats and re-assemble. Most of my jobs are 'never quite finished' because I always think that "whilst it's apart" there's room for improvement, and that certainly applies here.

regards, Phil

[Pinhead]

If you want to improve low-end torque, throttle response, fuel economy, and power, try this:



They're called Powre Lynz. Powre Lynz work with several laws of fluid dynamics to improve both power and economy. They:

- Work with the boundary layer of the intake ports to break up large liquid droplets into smaller droplets

- Act as a wick, holding liquid fuel against the heated port walls so the fuel vaporizes into the incoming air stream

- Liquid droplets will fall against the textured walls, the Powre Lynz will spread the fuel out radially increasing the surface area and make it easier to vaporize

- Powre Lynz add turbulence to the boundary layer to keep liquid fuel suspended in the air stream and prevent puddles and rivers of liquid fuel from forming

- Help create a cushion of air to improve flow and volumetric efficiency

They also create a variable boundary layer, which increases air velocity at low RPM, and "opens up" at high RPM for more flow.

http://fueleconomytips.com/2007/04/27/v ... ary-layer/
http://fueleconomytips.com/2006/12/13/powre-lynz/

[Volker_P]

That looks really interesting. I can imagine when you increase the boundary layer thickness that way, you can reduce wall interaction of mixture at low rpm as well as reduce the reverse flow. But probably you have to combine with a slight diameter increase to avoid losses at full throttle.

[Pinhead]

The loss at full throttle is so negligible that it's almost unmeasurable.

"PowreRingz" are basically the same thing on the back side of the intake valve. This mod alone is enough to increase low-lift blow by almost 30%. The increase at low RPM and low lift are more than enough to make up for the slight loss at WOT and full lift. The biggest advantage is the increase of velocity at low RPM, decreasing reversion and increasing torque.

[Pinhead]

ANYWAYS, back to the original topic...

Yea your parts look good Paul. I had a look at a 650 head just after I finished the work on my 500/550. Two different beasts to be sure. Just for your info, I cc'd the chambers on this one and they are exactly 13cc!

That's from SOCH4.

[Pinhead]

Bringing the old topic back to life...

What are the differences in the heads from '79 to 82? If I remember right, '79 and '80 are the same, and '81 and '82 are the same. Can I put a head out of an '82 on a '79 engine? What else would I need to facilitate the swap? I'm just asking because there aren't any '79 or '80 heads on ebay... I'd like to get one built up before I tear my bike down so I don't have as much downtime.

[Volker_P]

Just drop in for a warning: heads are interchangeable, however carb ports spacing is different for CV and piston carbs. Piston carbs are the earlier version but depending on countries it seems not that easy to fix it on the year alone. I think the black head (RC08) was made for CV carbs only.
Next week I will be back online and will try to contribute a bit more again. Meanwhile I did the first test ride with my CB again.