TOPIC:

As the title says. Thanks

Post edited by: caffcruiser, at: 2006/10/05 13:13

Im interested in this too, and since my head is off right now (the motor, not me:laugh: ) couldn't I just flip it over and fill one with liquid and find the volume that way? it may not be 100% accurate, but it would be quite close right?

If nobody has an answer, I'll try my idea this weekend

Post edited by: 77KZ650, at: 2006/10/05 14:26

That's the proper way to do it actually.

Problem is, you need a Burette and some plexiglass, some grease, some rubbing alcohal and some food dye.

I broke my burette.

Look in the links for the GPz750 Faq, if it's not in that one then It's in the other GPz750 Faq and you will have to Google for it.

One of them listed the cc's for the 650/750/GPz750 heads.

steell wrote:

Look in the links for the GPz750 Faq, if it's not in that one then It's in the other GPz750 Faq and you will have to Google for it.

One of them listed the cc's for the 650/750/GPz750 heads.

I checked the one in the "links" Section, and it's the same as the one that you find on google.

The only reference is:

"The 82 GPz750 has a combustion chamber volume of 24.9 cc which is very good. The 83-85 GPz750 have chamber volumes of 25.9 cc . The Kz750 H 24.8cc and Kz750 L 25.3 cc"

I need something more specific.

caffcruiser wrote:

That's the proper way to do it actually.

Problem is, you need a Burette and some plexiglass, some grease, some rubbing alcohal and some food dye.

I broke my burette.

hold on now, why all that stuff? cant I just get a measure of liquid, pour some of it into the the CC then see whats left? that would tell me how much I used to fill the CC... What am I missing here?

It was in the archives, "posted on 3-4-2005 at 16:38" by steell himself

The 650 Manual lists a combustion chamber volume of 23.7 cc

77KZ650 wrote:

caffcruiser wrote:

That's the proper way to do it actually.

Problem is, you need a Burette and some plexiglass, some grease, some rubbing alcohal and some food dye.

I broke my burette.

hold on now, why all that stuff? cant I just get a measure of liquid, pour some of it into the the CC then see whats left? that would tell me how much I used to fill the CC... What am I missing here?

Sure you can. You can also pretend that you can put together a motor while measuring the tolerances of critical parts with a ruler that you picked up at walmart.

When it comes to precision measuring in mechanics you don't want to slack by "doing well enough" with what you've got. There's a reason machinists don't measure things with a ruler when there's a dial caliper or micrometer around... because there's a way to get it done, and there's a RIGHT way to get it done.

You'd be amazed at how off a compression ratio calculation can be by just being +/- more than .5 mL of fluid in a chamber.

Now, if you're just doing stock stuff and you've got some room to play, feel free to measure some liquid and dump it in.

But if you're building a performance motor with closer tolerances (which I am) it's not worth the risk. Not to mention that if you fill a chamber with fluid you also have to consider that water will not sit flat on the top... it actually has a shape which is higher on the "rim" of chamber thanks to water tension, which needs to be accounted for as a negative volume if you don't have a cover on it to assure it has a flat surface.

Now add about 10 other places that have to be "compensated for" by not using the proper tools to do the job, and it's a huge migraine.

Post edited by: caffcruiser, at: 2006/10/05 19:17

Here is a link to the other GPz750 Faq, it shares some info with the one in the links section, but also has some that the other is missing.

members.tripod.com/gpz_rider/technical/FAQ2000.htm

caffcruiser wrote:

Sure you can. You can also pretend that you can put together a motor while measuring the tolerances of critical parts with a ruler that you picked up at walmart.

When it comes to precision measuring in mechanics you don't want to slack by "doing well enough" with what you've got. There's a reason machinists don't measure things with a ruler when there's a dial caliper or micrometer around... because there's a way to get it done, and there's a RIGHT way to get it done.

You'd be amazed at how off a compression ratio calculation can be by just being +/- more than .5 mL of fluid in a chamber.

Now, if you're just doing stock stuff and you've got some room to play, feel free to measure some liquid and dump it in.

But if you're building a performance motor with closer tolerances (which I am) it's not worth the risk. Not to mention that if you fill a chamber with fluid you also have to consider that water will not sit flat on the top... it actually has a shape which is higher on the "rim" of chamber thanks to water tension, which needs to be accounted for as a negative volume if you don't have a cover on it to assure it has a flat surface.

Now add about 10 other places that have to be "compensated for" by not using the proper tools to do the job, and it's a huge migraine.

Im building a performance motor myself. Its not like I was going to use a measuring cup to see how much fluid I used.
You didnt explain the procedure that you do though, why don't you enlighten me? I'll try it and compare results to the actual volume

Post edited by: 77KZ650, at: 2006/10/05 20:34

Look up "Finding combustion chamber volume" on the interweb. There's more than a bazillion pages that cover this because it's the only proper way to find out the volumetric capacity of a domed or otherwise irregular area.

***Note that Summit Racing sells the kit that I was recommending you put together to do this job for $129.00 I think. That's a $30.00 burette, and a $100.00 piece of plexiglass!

You can get the stuff to properly CC out heads and cylinders much cheaper than you'd probably imagine.

Burette- $30.00
Plexiglass- free at the hardware store. You need a piece of scrap 5"x5".
Sealant- $2.00 Vasoline will work
Water- Free
Coloring- $3.00
Drilling a hole- nothing if you have any tools at all.

$35.00 and you can properly CC heads, pistons, etc.

Not a bad deal for a job done right.

Also, you can try, but you won't be able to get anywhere near accurate just measuring water and dumping it in without a burette. That is, unless you have some other piece of labware gradiated in CC's or mL's.

Almost done at work, and bored, so I thought this may be pertinant.

"The tools necessary for this measurement job are about the same ones used when "cc’ing" cylinder heads. You’ll need a 100cc burette (a glass cylinder graduated in cubic centimeters, with a valve at the bottom) and stand, available at medical supply houses. A six by six inch piece of flat Plexiglas with a hole in the center is next, and a couple of bottles of isopropyl alcohol (rubbing alcohol). We add a little machinist’s dykem to the alcohol to give it color, making the graduations in the burette easier to read. Another item, which should be on the list, is the all-American handy dandy pocket calculator. Working with figures with six or more digits and keeping track of the decimals can be a pain without one. Accuracy is extremely important: a mere 3cc error is enough to throw your final figure off by a half point, say from 12:l to 11.5:1."

That should answer your question anyhow. Without the proper equipment you won't be able to get within 3 cc's of measurement. Building a high performance motor and being off by 1/2 a point on your compression ratio could be a very costly mistake!

As you see, 3 cc's can be 1/2 point. You can try it yourself, but this test isn't soemthing to base ALL motors on obviously. You think that Kawasaki was real picky about making sure all the chamber volumes on their heads in the 1970's were the correct and identical? Not even close.

This is more of a specified check to see what the compression ratio of YOUR motor will be. I'm using it to find necessary gasket thickness. The gasket thickness in the formula for compression ratio will be my variable. Most people use it to find out the compression ratio, not the gasket thickness. Different strokes I guess.
By the way, I wasn't calling you an idiot by any means. Please don't infer that I was.

Post edited by: caffcruiser, at: 2006/10/05 20:03