How much "in the hole" (piston @ TDC)

[Pop-pop2]

Putting a S.E. 103 together. How much "down" in the cylinder is too much for cr 575 cams ? Supposed to be @ 10.3:1 compression.

[kd]

Take all your info and run it through the Big Boyz compression calculator.  You'll need to know your head CC's, deck height, piston info (incl valve relief), bore and stroke (select 103 cu in the calculator). 

[Armin]

If you have set your pistons to zero deck height you need to know your valve lift at TDC and the valve pocket depth of your pistons from manufacturer specs. Best thing would be a clay check.

Armin.

[Don D]

Randy, Hyperformance has a youtube video how to check P to V clearance. It is a better method than clay. The clay method can bend valves. When I have everything here it is easy to check with the barrel on top of the head with trock to open the valves and clay on the domes then just shove them in.

[Hillside Motorcycle]

Putting a S.E. 103 together. How much "down" in the cylinder is too much for cr 575 cams ? Supposed to be @ 10.3:1 compression.

Several calculators out there to help.
We have several of the Craig Walters versions.

[Pop-pop2]

  Ok, my bad.  After seeing the replies,  my question should have been. How far can the "piston" be down in the cylinder ?

[PoorUB]

Flush with the top is best. You can use a thinner head gasket to offset a few thousanths down the hole. If you have the heads off, why not machine them to zero deck?

[kd]

 

[Pop-pop2]

Already sent them off an got them back.  Didn't know to measure them when I took it apart.
I never had to worry about that with diesels, so I didn't measure it. Putting it back together with. 030" head gaskets. Heads are ported, forged pistons. Trying to do it right,  just don't know if pistons .007" below the deck is going to be a problem.

[nosjunkie]

Zero Deck height with a .030 head gasket gives you an optimal quench area....

[PoorUB]

I would be sending the cylinders back and have the .007" trimmed off if it were mine.

[jrgreene1968]

I would be sending the cylinders back and have the .007" trimmed off if it were mine.

I agree.

[HD/Wrench]

Piston to valve is so basic and simple to do , you need nothing but a basic caliper and masking tape.

Remove valve springs set head on cylinder with No gasket.

Take the Valve and push it down until it makes contact with piston . Take your tape and put it on valve where the seal is at do this on the other valve as well

Remove head measure with caliper . It will get you as close as you need . Add in HG thickness + 60 for intake and 80 for ex and minus from your TDC lift and your done.

Clay does not work unless you have a solid lifter .

[Pop-pop2]

Poor UB and JR could you elaborate as to why you would have them decked the .007" ?
I have my suspicions, but I would like to hear your reasonings.
TIA

[Ohio HD]

Already sent them off an got them back.  Didn't know to measure them when I took it apart.
I never had to worry about that with diesels, so I didn't measure it. Putting it back together with. 030" head gaskets. Heads are ported, forged pistons. Trying to do it right,  just don't know if pistons .007" below the deck is going to be a problem.

0.037" will be fine on a street ridden motor.

[jrgreene1968]

Poor UB and JR could you elaborate as to why you would have them decked the .007" ?
I have my suspicions, but I would like to hear your reasonings.
TIA

Compression will be lower than set at 0, squish's will be increased, chances of pinging are greater . Look up your specs on Bigboyz calculator.. pretty good difference from 0 to .007
It will run at .007, no doubt , but I'm ocd on everything I do

[harpwrench]

What did the head porter set the cc's to?

[harpwrench]

Are the pistons flat top or dome?

[Coff 06]

Are they both.007? Between.005-.007 is about average I believe.Most people would have them done to equal the compression between the cylinders.Get an optimum squish gives you the best fire in the combustion chamber. JMO.         Coff 06

[PoorUB]

I agree with all of the above, including that it will run fine for a street engine. On the other hand You have it apart, just time and a few dollars in shipping will make it right. It would bug me to have it apart this far and not do it. You will be loosing about .15 of the compression ratio, 3-4 PSI of cranking compression, so not a huge deal,also the squish will be .037", where tighter is better, to a point.

Your call, only you can decide how much money you want to spend, and how exact you want the final result to be. My last go round I left the heads on, slapped in cams, exhaust and tune and called it good.

[Pop-pop2]

Heads are 94.8 cc ('03 Screamin Eagle heads), dome pistons, both are .007" below deck.
My concern is pinging. Why make it more difficult to tune than necessary. Am I out in left field on this one

[rigidthumper]

Heads are 94.8 cc ('03 Screamin Eagle heads), dome pistons, both are .007" below deck.
My concern is pinging. Why make it more difficult to tune than necessary. Am I out in left field on this one

We need some clarification:
What year bike? 2003 RK?  Didn't think Cycle Rama made a cr575 for 99-06 touring bikes.
What pistons do you have?
I ask, because the 103 CVO pistons from Arias (22444-02) were only 5cc domes, and brought the CVO 103 engines to 9.5:1 with a .040 HG, and 9.7:1 with a .030 HG.

[Pop-pop2]

'03 cvo road king. Keith Black - KB660C + .010 pistons. Cycle-Rama gear drive cr575 cams, .030 head gaskets.

[rigidthumper]

'03 cvo road king. Keith Black - KB660C + .010 pistons. Cycle-Rama gear drive cr575 cams, .030 head gaskets.

Those should be 10.7 cc domes, putting you at ~10.25:1, 9.6 corrected, and should crank about 200 PSI. Good area for a street bike with a good tune.

[Pop-pop2]

Ok, back to the. 007" below deck question. Should this be corrected ? Will this make it more difficult to tune ? Have TTS for tuner.