Too much compression

[hogrdr]

I have a 2001 Heritage Softail with Screaming Eagle crank. I had case machine for 4 1/8 Pistons. I had a 117 S&S kit installed come to find out the cylinders was not true. Have them bored 10 over with 10 over new Pistons. The Pistons are set at .003 above deck..020 base gasket and .040 head gasket. My cranking compression has 225. I put on CVO 110 heads CC. 92. 585 cam. Is there a way to bring my compression down? Engine pings. Thanks

[rigidthumper]

1) An adjustable ignition is your friend.
2) Your numbers don't add up, unless the crank-cam timing is off.
3) A .010" over 117 flat top, .003' proud, with a 40 thou thick head gasket and 92 cc heads is 10.46:1, and that cam (45° close) should have ~196 PSI CCP.

[MikeL]

I went to this site
http://bigboyzheadporting.com/TwinCamComp.htm
and plugged in your specs and got 10.34 static compression, 9.31 corrected compression.Flat top pistons? Was the compression test done hot? Retest compression with another test gauge to confirm 225 is way high
Is the bike carb? Is it fuel injected?
Your going to have to dial back on spark timing. Carb bike your gonna need an after market module that is spark adjustable. If it's a M/M P/C 3 and god help you with that.

                                                                                                                                                                    MIKE

[hogrdr]

1) An adjustable ignition is your friend.
2) Your numbers don't add up, unless the crank-cam timing is off.
3) A .010" over 117 flat top, .003' proud, with a 40 thou thick head gasket and 92 cc heads is 10.46:1, and that cam (45° close) should have ~196 PSI CCP.

I will check my timing today

[hogrdr]

1) An adjustable ignition is your friend.
2) Your numbers don't add up, unless the crank-cam timing is off.
3) A .010" over 117 flat top, .003' proud, with a 40 thou thick head gasket and 92 cc heads is 10.46:1, and that cam (45° close) should have ~196 PSI CCP.

I will check my crank cam

[hogrdr]

I went to this site
http://bigboyzheadporting.com/TwinCamComp.htm
and plugged in your specs and got 10.34 static compression, 9.31 corrected compression.Flat top pistons? Was the compression test done hot? Retest compression with another test gauge to confirm 225 is way high
Is the bike carb? Is it fuel injected?
Your going to have to dial back on spark timing. Carb bike your gonna need an after market module that is spark adjustable. If it's a M/M P/C 3 and god help you with that.

                                                                                                                                                                    MIKE

yes the cranking compression was checked hot and I did have my compression tester check and it was good

[hogrdr]

I went to this site
http://bigboyzheadporting.com/TwinCamComp.htm
and plugged in your specs and got 10.34 static compression, 9.31 corrected compression.Flat top pistons? Was the compression test done hot? Retest compression with another test gauge to confirm 225 is way high
Is the bike carb? Is it fuel injected?
Your going to have to dial back on spark timing. Carb bike your gonna need an after market module that is spark adjustable. If it's a M/M P/C 3 and god help you with that.

                                                                                                                                                                    MIKE

carbureted

[Hossamania]

Are you running stock ignition?

[Don D]

Only seen it once on an early 103 with the same Jims crank. The flat was  misoriented.

[hogrdr]

1) An adjustable ignition is your friend.
2) Your numbers don't add up, unless the crank-cam timing is off.
3) A .010" over 117 flat top, .003' proud, with a 40 thou thick head gasket and 92 cc heads is 10.46:1, and that cam (45° close) should have ~196 PSI CCP.

cam crank timing is correct

[Ohio HD]

I went to this site
http://bigboyzheadporting.com/TwinCamComp.htm
and plugged in your specs and got 10.34 static compression, 9.31 corrected compression.Flat top pistons? Was the compression test done hot? Retest compression with another test gauge to confirm 225 is way high
Is the bike carb? Is it fuel injected?
Your going to have to dial back on spark timing. Carb bike your gonna need an after market module that is spark adjustable. If it's a M/M P/C 3 and god help you with that.

                                                                                                                                                                    MIKE

yes the cranking compression was checked hot and I did have my compression tester check and it was good

How was the compression tester checked for accuracy?

[hogrdr]

Are you running stock ignition?

using twin Tech tc88

[Hossamania]

Are you running stock ignition?

using twin Tech tc88

What are your settings?
Have you checked for vacuum leaks?

[hogrdr]

1 timing -1 slope. That is where I get the least ping. I tried timing 1 and all the slopes timing to all the slopes and 1 and 1 was the best. Going to take it in and have a dial indicator put on it and see where I'm at

[ThumperDeuce]

Put a cam in with more overlap and enjoy the ride.

[Hossamania]

Might have to do an afr check to see where you're at.
Which carb are you using?

[Hossamania]

Fuel, have you tried different gas stations, brands? Running premium, 91 - 93 octane?

[hogrdr]

Fuel, have you tried different gas stations, brands? Running premium, 91 - 93 octane?

I have a AFR on the bike at cruising speed it runs between 34 and 32

[hogrdr]

Fuel, have you tried different gas stations, brands? Running premium, 91 - 93 octane?

I have a AFR on the bike at cruising speed it runs between 34 and 32

93 octane yesterday I tried 100% gas no changes

[hogrdr]

Might have to do an afr check to see where you're at.
Which carb are you using?

what cam do you recommend

[hogrdr]

Might have to do an afr check to see where you're at.
Which carb are you using?

45 Mikuni and I have an AFR she runs at 34 32 cruising speed

[hogrdr]

1) An adjustable ignition is your friend.
2) Your numbers don't add up, unless the crank-cam timing is off.
3) A .010" over 117 flat top, .003' proud, with a 40 thou thick head gasket and 92 cc heads is 10.46:1, and that cam (45° close) should have ~196 PSI CCP.

[rigidthumper]

Remove the plugs, set rear to TDCC, and verify the flat on the crank is pointing exactly inline with the center of the rear cylinder with a t-square.
That is a rough check on the crank flat being machined properly.

[hogrdr]

Fuel, have you tried different gas stations, brands? Running premium, 91 - 93 octane?

I have a AFR on the bike at cruising speed it runs between 13.2-13.4

[MikeL]

Check for case sumping. This could add load on the engine causing detonation.

                                                                                                                                                               MIKE