Setting compression after CC'ing heads.

[Don D]

On the fluid to use. I like windshield washer fluid. It does not bubble when filling and has less meniscus than plain water. Cheap and not toxic.

[kd]

On the fluid to use. I like windshield washer fluid. It does not bubble when filling and has less meniscus than plain water. Cheap and not toxic.

    Learning to read the meniscus is key and critical.  In a tube it must be perpendicular to the graduation marks too.

[FXDBI]

On the fluid to use. I like windshield washer fluid. It does not bubble when filling and has less meniscus than plain water. Cheap and not toxic.

I think the " meniscus" effect is neutralized with the use of a syringe. All entrapped air is removed before use and none should re-enter with proper use. The measurement will be close enough for the home guy not selling his services has a professional. Not a ISO standard but why complicate things, a little food coloring in the water works well. I use the KISS method same way the engine is designed simple. No disrespect to anyone just what has worked for me.   Bob

[kd]

I guess it wasn't clear but I used the tube as an example for reading a meniscus line only and the need for it to be perpendicularly square.  The colored washer fluid works well in both rather than clear.

[billbuilds]

On the fluid to use. I like windshield washer fluid. It does not bubble when filling and has less meniscus than plain water. Cheap and not toxic.

    Learning to read the meniscus is key and critical.  In a tube it must be perpendicular to the graduation marks too.

     Thanks for that info kd and HD Street Performance. I got my plexiglass cut and hole drilled. Did a bunch of running around yesterday that I would usually ddo on the weekend so hopefully I can lay low for the storm. I'd seen where Summmit Racing had recommended a 50/50 mix of rubbing alcohol and water then add food coloring. I found some rubbing alcohol at the CVS Pharmacy that has a green tint. It was getting late yesterday afternoon and I wanted to start fresh this morning. Let's see how this goes. 

[billbuilds]

     I used a 60cc and a 12cc syringe because they were handy and cheap. Did each head three times and I found the front one to be about 78.5cc and the rear to be about 79.5cc.

     I ran the Big Boyz caclulator for 98" using 80cc as head volume, putting the pistons .0005 in the hole, pistons having a 10.40 dome volume and S$S 570's. With an 045 head gasket it shows a corrected compression of 10.15:1 and 215.8 ccp. Is that a little high or should it be ok seeing as I was a little conservative with the actual head volume figure in my figuring?   

[kd]

Actually you weren't conservative with the head volume Your measurement shows a smaller volume which relates to higher compression than you calculated.  Rerun the numbers at 79 CC and you'll see what I mean. Then run it again with a .030 head gasket. The .045  head gasket isn't favorable to controlling detonation like a .030 is either.) With a good tuner and tuning device you may still be OK but the head gasket size may be better at the .030 for control of pinging.

[Ohio HD]

I really depends on how you wish to use the motor. If a cruiser, the compression may be a little high. If a lighter bike, and will be a play bike, less issues. It also depends on if there is ample 93 octane in your area. 

I'm calculating about 10.40 corrected compression. That's pretty high. If you're at a higher elevation then that helps reduce the cylinder pressure.

[billbuilds]

Actually you weren't conservative with the head volume Your measurement shows a smaller volume which relates to higher compression than you calculated.  Rerun the numbers at 79 CC and you'll see what I mean. Then run it again with a .030 head gasket. The .045  head gasket isn't favorable to controlling detonation like a .030 is either.) With a good tuner and tuning device you may still be OK but the head gasket size may be better at the .030 for control of pinging.

     Yes, I meant that I rounded up the head volume number because I had an idea that the corrected compression and ccp were going to be on the high side anyhow. If I plug in the .030  head gasket, even with the 80cc head volume number, it's where I don't even want to try it - 10.5:1 compression and 225.3ccp.   

[billbuilds]

I really depends on how you wish to use the motor. If a cruiser, the compression may be a little high. If a lighter bike, and will be a play bike, less issues. It also depends on if there is ample 93 octane in your area. 

I'm calculating about 10.40 corrected compression. That's pretty high. If you're at a higher elevation then that helps reduce the cylinder pressure.

     No, it's not a lighter bike, it's a Road King. This was made very clear to the shop. No, you can't always find 93 octane around here sometimes the high is 91. Really don't want to play that game. When the guy at Campbell Industriestold me the compression of these CP pistons my immediate thought was "ping monster". The bike is carbed.
     This really bums me out because I went over exactly who did these 06 heads of mine before I shipped them down to him so that he could measure them, clean them up and install new springs in them. He knew that they weren't stock. It's pretty obvious that he did not bother to measure the chamber volume but just spun them up and shaved the .030 off of them. They'd obviously had some taken off before.
     I really thought that he was going to give me the 9.5:1 pistons seeing as the Rev Perfs were 9.5:1. There was a difference in valve pocket size and we spoke in detail about that. It was left that he'd measure the heads and make the decision. Ok, I'd better stop or I'm going to get this thread locked. Thanks, Bill

                                       

[rigidthumper]

IMO, Flat tops and those 570s would make an easy to tune/no drama build. If there's enough meat on those pistons, chuck em up in a lathe, remove the domes, and get er done...

[Ohio HD]

I assume these are the CP Bullet style pistons? I think they're designed to allow a flat top if milled down.

You might see about talking to someone at CP, explain what you have, and ask them how much less compression or rather cc's you have when milling every 0.010" off the piston dome. And ask if they can be milled flat if desired.

[Ohio HD]

As calculated, a flat top would give you about 9:1 or 182ccp. A flat top you have to calculate negative dome for the valve reliefs. A 2cc dome you would have about 9.45:1, or 193ccp.

Just estimates on the ccp of course.

[billbuilds]

I assume these are the CP Bullet style pistons? I think they're designed to allow a flat top if milled down.

You might see about talking to someone at CP, explain what you have, and ask them how much less compression or rather cc's you have when milling every 0.010" off the piston dome. And ask if they can be milled flat if desired.

     Yes, they're the Bullet style though the one descrepancy between the spec sheet that I got and the list that you included in your reply to my piston question thread is that my spec sheet shows dome hieght as 10.40 whereas the listing shows dome height at an even 10. I'll call Campbell Industries tomorrow morning as they're three hours ahead of CP Carillo time zone-wise. If they're not sure I'll just have to wait and call Cali.  Thanks, Bill

[Don D]

The deck must remain .200 thick at all points. If there is under deck milling often times the amount that can be cut is minimal. There are also limits even when the deck is thick enough. The forging can distort.

[billbuilds]

The deck must remain .200 thick at all points. If there is under deck milling often times the amount that can be cut is minimal. There are also limits even when the deck is thick enough. The forging can distort.

      Thanks for the reply. I had an idea that there would be limits to how much material could be safely shaved off. I'm no machinist but I did work in a machine shop for several years. I would guess that the optimal way to shave that material off would be in a lathe, a high tech lathe that has cutting/cooling fluid being directed onto the tool/part contact area. That's not going to be a cheap procedure. 

[Buglet]

   Make sure either way you do it is that you have a good way to hold the piston so it don't get distorted either on a lathe or a mill is most important.

[billbuilds]

     I just got off the phone with CP-Carillo and the guy I spoke with said no, can't turn these into flat tops as they'd be too thin. Houston, we have a problem.

[kd]

It's beginning to look like all of this heart wrenching problem solving will be best addressed with a new set of pistons with more appropriate specifications.  The ones you have may be sold or repurposed in another build.

[cheech]

It's beginning to look like all of this heart wrenching problem solving will be best addressed with a new set of pistons with more appropriate specifications.  The ones you have may be sold or repurposed in another build.

My thought from the get go.

[billbuilds]

It's beginning to look like all of this heart wrenching problem solving will be best addressed with a new set of pistons with more appropriate specifications.  The ones you have may be sold or repurposed in another build.

    With my cylinders already bored to supposedly fit these pistons what are the chances that newer, lower compression pistons will fit to spec?

[kd]

If too tight, that's adjustable.  If too loose, coatings are showing a lot of promise.  That's 2 options I see.

[billbuilds]

     I'm shelving this project or now and going another route to seek a "soution". I've got way too much money invested in this already to start throwing good money after bad. Thanks to all for the help, Bill

[harpwrench]

If it were mine I would install a mackie 598 with a -4 crank sprocket, and enjoy the power

[billbuilds]

If it were mine I would install a mackie 598 with a -4 crank sprocket, and enjoy the power

     That's 11.57:1 static and 9.85:1 corrected. Wouldn't it be pushing thing with a nearly 208ccp?