Deck heads or hi comp pistons

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Mar 3, 2012 | 07:58 AM

txphatboy

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Road Warrior

Joined: Jul 2011

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From: Central TX

Deck heads or hi comp pistons

I am going to purchase big bore kit with street port heads for my TC88 in the next couple weeks. Want to stay in 9.7 - 9.8 compression range with the 204 cams already in bike. One kit I am looking at comes with 9.7 pistons, the other 9.5 and the heads are decked to give 9.7. Does decking the heads give any other benefit to engine running more efficiently, or is it just done to bump compression, and the 9.7 CR on both kits will give same performance?

Mar 3, 2012 | 08:40 AM

SteveO-ll

Outstanding HDF Member

Joined: Jul 2010

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From: Smack Dab in the Middle of Louisiana

If you are going to get that particular about the build (which by no means a bad thing), I would look to see the differences between the weight and mass of the pistons themselves.

Mar 3, 2012 | 08:50 AM

LAMing

Road Master

Joined: Nov 2007

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From: Eastern Oklahoma

So you're having a problem with di#k heads or their hi-comp bikes? What else is new?

Oh wait, you said DECK heads. My bad.

Mar 3, 2012 | 10:44 AM

txphatboy

Thread Starter

Road Warrior

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From: Central TX

The 9.7 compression pistons are part of a S&S 97 big bore kit, but not sure about piston specs. The other kit is a 95 BB from Dunnperformance. Looks like he does a real nice job on the heads - not sure about weight of pistons, but I know they are Ross forged.

Mar 3, 2012 | 12:03 PM

loafeRebel

Cruiser

Joined: Feb 2012

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From: America

Might want to think about dropping weight in your flywheel (crankshaft), rods & primary along with making sure the valves clear the TDC of the piston.

Mostly, I work for a living & know only so much.

Mar 3, 2012 | 01:11 PM

txphatboy

Thread Starter

Road Warrior

Joined: Jul 2011

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From: Central TX

That is the first time I have heard of getting into crankshaft, primary, etc for a basic big bore. Sounds expensive and more than I am looking to get into with this build.

Mar 3, 2012 | 04:41 PM

RHPAW

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Joined: Aug 2007

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From: Driftless Area

A few years back, we did two top ends with cams, pushrods, etc. On mine, we shaved the heads .050". On the other, HC pistons. That was the only difference. I did notice the one with the HC pistons always seemed to turn over an extra couple of times before starting. They seemed to be equal in all other performance, not sure why the quicker starting, but I still have the original starter in mine years later with no issues.